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Simeon P, Unkovskiy A, Saadat Sarmadi B, Nicic R, Koch PJ, Beuer F, Schmidt F. Wear resistance and flexural properties of low force SLA- and DLP-printed splint materials in different printing orientations: An in vitro study. J Mech Behav Biomed Mater 2024; 152:106458. [PMID: 38364445 DOI: 10.1016/j.jmbbm.2024.106458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 01/29/2024] [Accepted: 02/05/2024] [Indexed: 02/18/2024]
Abstract
OBJECTIVES To investigate the influence of material and printing orientation on wear resistance and flexural properties of one low force SLA- and two DLP-printed splint materials and to compare these 3D-printed splints to a subtractively manufactured splint material. METHODS Two DLP-printed (V-Print splint, LuxaPrint Ortho Plus) and one low force SLA-printed (Dental LT Clear) material, where specimens were printed in three printing orientations (0°, 45°, 90°), were investigated. In addition, one milled splint material (Zirlux Splint Transparent) was examined. A total of 160 specimens were produced for both test series. The two-body wear test was performed in a chewing simulator (80'000 cycles at 50 N with 5-55 °C thermocycling). Steatite balls were used as antagonists. The wear pattern was analyzed with a 3D digital microscope in terms of maximum vertical intrusion depth (mm) and total volume loss (mm³). The flexural properties were investigated by three-point bending in accordance with ISO 20795-1: 2013 (denture base polymers). The flexural strength (MPa) and the flexural modulus (MPa) were measured. Two-way ANOVA was performed to investigate the effects of the two independent variables material and printing orientation for the three 3D-printed materials. The comparison of the printing orientations within one material was carried out with one-way ANOVA with post-hoc Tukey tests. RESULTS Two-way ANOVA revealed that wear and flexural properties are highly dependent on the 3D-printed material (p < 0.001). Across groups, a significant effect was observed for wear depth (p = 0.031) and wear volume (p = 0.044) with regard to printing orientation but this was not found for flexural strength (p = 0.080) and flexural modulus (p = 0.136). One-way ANOVA showed that both DLP-printed groups showed no significant differences within the printing orientations in terms of wear and flexural properties. Dental LT Clear showed that 90° oriented specimens had higher flexural strength than 0° oriented ones (p < 0.001) and 45° oriented specimens also showed higher values than 0° ones (p = 0.038). No significant differences were observed within the printing orientations for flexural modulus and wear behaviour within this group. T-tests showed that the milled splints exhibited statistically higher wear resistance and flexural properties compared to all three 3D-printed splint materials (p < 0.001) and that highly significant differences were found between the 3D-printed splint materials for both test series. CONCLUSION Within the limitations of this in vitro study, it can be stated that wear behaviour and flexural properties are highly dependent on the 3D-printed material itself. Currently, milled splints exhibit higher wear resistance and flexural properties compared to 3D-printed splint materials. The printing orientation has a minor influence on the properties investigated. Nevertheless, two-way ANOVA also showed a significant influence of printing orientation in the wear test across groups and one-way ANOVA detected significant effects for SLA material in terms of flexural strength, with printing in 90° showing the highest flexural strength. Therefore, anisotropy was found in SLA material, but it can be limited with the employed printing parameters. Both DLP-printed materials showed no significant difference within the printing orientation.
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Affiliation(s)
- Philipp Simeon
- Charité - Universitätsmedizin Berlin, Center for Oral Health Sciences CC3, Department of Prosthodontics, Geriatric Dentistry and Craniomandibular Disorders, Aßmannshauser Str. 4-6, 14197, Berlin, Germany
| | - Alexey Unkovskiy
- Charité - Universitätsmedizin Berlin, Center for Oral Health Sciences CC3, Department of Prosthodontics, Geriatric Dentistry and Craniomandibular Disorders, Aßmannshauser Str. 4-6, 14197, Berlin, Germany; Department of Dental Surgery, Sechenov First Moscow State Medical University, Bolshaya Pirogovskaya Street, 19с1, Moscow, 119146, Russia
| | - Bardia Saadat Sarmadi
- Charité - Universitätsmedizin Berlin, Center for Oral Health Sciences CC3, Department of Prosthodontics, Geriatric Dentistry and Craniomandibular Disorders, Aßmannshauser Str. 4-6, 14197, Berlin, Germany
| | - Robert Nicic
- Charité - Universitätsmedizin Berlin, Center for Oral Health Sciences CC3, Department of Prosthodontics, Geriatric Dentistry and Craniomandibular Disorders, Aßmannshauser Str. 4-6, 14197, Berlin, Germany
| | - Petra Julia Koch
- Charité - Universitätsmedizin Berlin, Center for Oral Health Sciences CC3, Department of Orthodontics and Orthofacial Orthopedics, Aßmannshauser Str. 4-6, 14197, Berlin, Germany
| | - Florian Beuer
- Charité - Universitätsmedizin Berlin, Center for Oral Health Sciences CC3, Department of Prosthodontics, Geriatric Dentistry and Craniomandibular Disorders, Aßmannshauser Str. 4-6, 14197, Berlin, Germany
| | - Franziska Schmidt
- Charité - Universitätsmedizin Berlin, Center for Oral Health Sciences CC3, Department of Prosthodontics, Geriatric Dentistry and Craniomandibular Disorders, Aßmannshauser Str. 4-6, 14197, Berlin, Germany.
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Bresser RA, Carvalho MA, Naves LZ, Melma H, Cune MS, Gresnigt MMM. Biomechanical behavior of molars restored with direct and indirect restorations in combination with deep margin elevation. J Mech Behav Biomed Mater 2024; 152:106459. [PMID: 38394767 DOI: 10.1016/j.jmbbm.2024.106459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/30/2024] [Accepted: 02/05/2024] [Indexed: 02/25/2024]
Abstract
STATEMENT OF PROBLEM The existing knowledge is insufficient for comprehending the fatigue survival and fracture resistance of molars that have deep approximal direct and indirect restorations, whether with or without deep margin elevation (DME). PURPOSE The aim of this laboratory and in silico study is to investigate the fatigue survival, fracture strength, failure pattern and tooth deformation of molars restored with DME in combination with a direct or indirect restoration. MATERIAL AND METHODS This study utilized 45 extracted sound human molars, divided into three groups (n = 15). Standardized 100% inter-cuspal inlay preparations were performed, extending 2 mm below the CEJ and immediate dentin sealing (IDS) was applied. Group 1 (Co_1) was restored with direct composite; Group 2 (Hyb_2) with a 2 mm DME of direct composite and a glass-ceramic lithium disilicate restoration; Group 3 (Cer_3) a glass-ceramic lithium disilicate restoration. All specimens were exposed to a fatigue process involving thermal-cyclic loading (50N for 1.2 × 106 cycles at 1.7 Hz, between 5 and 55 °C), if teeth survived, they were fractured using a load-to-failure test and failure types were analyzed. Finite element analysis (FEA) was conducted to assess tooth deformation and tensile stress in the restorations. Statistical evaluation of fracture strength was conducted using the Kruskal-Wallis test. Fisher's exact test was utilized to analyze the fracture types and repairability. A statistical significance level of α < 0.05 was set for all analyses. RESULTS All specimens successfully withstood the fatigue testing procedure, and no statistically significant differences in fracture strength were observed among the three groups (P > 0.05). The Fisher's exact test indicated a significant association between the restorative material and fracture type (F2 = 18.315, df = 2, P = 0.004), but also for repairability (F2 = 13.725, df = 2, P = 0.001). Crown-root fractures were significantly more common in the Cer_3 group compared to the Co_1 group (P = 0.001) and the Co_1 group had significantly more repairable fractures (F2 = 13.197, df = 2, P = 0.001). FEA revealed comparable outcomes of deformation among models and higher maximum tensile stress on models with higher frequency of catastrophic failures. CONCLUSIONS All tested restoration materials exhibited comparable fatigue survival and fracture strength in this laboratory and in silico study. However, it is important to recognize the potential for more severe and irreparable fractures when opting for deeply luted glass-ceramic inlay restorations in clinical practice. In such cases, it would be prudent to consider the alternative option being a direct composite approach, because of its more forgiving fracture types and repairability. CLINICAL IMPLICATIONS Molars with deep approximal direct and indirect restorations, whether with or without DME, are comparable in their fatigue survival and fracture resistance to withstand intra-oral forces. Deep direct restorations exhibit more repairable fractures compared to deeply luted glass-ceramics.
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Affiliation(s)
- Rijkje A Bresser
- University of Groningen, University Medical Center Groningen, Center for Dentistry and Oral Hygiene, Department of Restorative Dentistry, Groningen, the Netherlands.
| | - Marco A Carvalho
- Dental School, Evangelical University of Goias, Anapolis, Brazil
| | - Lucas Z Naves
- University of Groningen, University Medical Center Groningen, Center for Dentistry and Oral Hygiene, Department of Restorative Dentistry, Groningen, the Netherlands
| | - H Melma
- University of Groningen, University Medical Center Groningen, Center for Dentistry and Oral Hygiene, Department of Restorative Dentistry, Groningen, the Netherlands
| | - Marco S Cune
- University of Groningen, University Medical Center Groningen, Center for Dentistry and Oral Hygiene, Department of Restorative Dentistry, Groningen, the Netherlands; St. Antonius Hospital Nieuwegein, Department of Oral Maxillofacial Surgery, Prosthodontics and Special Dental Care, Nieuwegein, the Netherlands
| | - Marco M M Gresnigt
- University of Groningen, University Medical Center Groningen, Center for Dentistry and Oral Hygiene, Department of Restorative Dentistry, Groningen, the Netherlands; Martini Hospital, Department of Special Dental Care, Groningen, the Netherlands
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Temizci T, Bozoğulları HN. Effect of thermal cycling on the flexural strength of 3-D printed, CAD/CAM milled and heat-polymerized denture base materials. BMC Oral Health 2024; 24:357. [PMID: 38509542 PMCID: PMC10953149 DOI: 10.1186/s12903-024-04122-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 03/07/2024] [Indexed: 03/22/2024] Open
Abstract
BACKGROUND This study compared the impact of thermal cycling on the flexural strength of denture-base materials produced through conventional and digital methods, using both subtractive and additive approaches. METHODS In total, 60 rectangular specimens were fabricated with specific dimensions for flexural strength tests. The dimensions were set according to the International Organization for Standardization (ISO) guideline 20795-1:2013 as 64 × 10 × 3.3 ± 0.2 mm. Specimens from each material group were divided into two subgroups (thermal cycled or nonthermal cycled, n = 10/group). We used distinct methods to produce three different denture-base materials: Ivobase (IB), which is a computer-aided-design/computer-aided-manufacturing-type milled pre-polymerized polymethyl methacrylate resin disc; Formlabs (FL), a 3D-printed denture-base resin; and Meliodent (MD), a conventional heat-polymerized acrylic. Flexural strength tests were performed on half of the samples without a thermal-cycle procedure, and the other half were tested after a thermal cycle. The data were analyzed using a two-way analysis of variance and a post hoc Tukey test (α = 0.05). RESULTS Based on the results of flexural-strength testing, the ranking was as follows: FL > IB > MD. The effect of thermal aging was statistically significant for the FL and IB bases, but not for the MD base. CONCLUSIONS Digitally produced denture bases exhibited superior flexural strength compared with conventionally manufactured bases. Although thermal cycling reduced flexural strength in all groups, the decrease was not statistically significant in the heat-polymerized acrylic group.
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Affiliation(s)
- Tuğba Temizci
- Department of Prosthodontics, Faculty of Dentistry, Karamanoğlu Mehmetbey University, Karaman, Turkey.
| | - Hatice Nalan Bozoğulları
- Department of Prosthodontics, Faculty of Dentistry, Karamanoğlu Mehmetbey University, Karaman, Turkey
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Reffaee A, Saied M, Hamieda SF, Amin SK. Fabrication of green anti-microbial and anti-static cement building bricks. Sci Rep 2024; 14:6313. [PMID: 38491047 PMCID: PMC10943018 DOI: 10.1038/s41598-024-56514-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 03/07/2024] [Indexed: 03/18/2024] Open
Abstract
The design cement mix of grade 350 was created in accordance with Egyptian Standards by partially substituting the fine aggregate with WPVC waste in various weight percentages (10, 20, 30, 40, 50, 75, and 100%). A control mix with 0% replacement was also prepared. The W/C ratio was about 0.5 for all mixes. Compressive, flexure strength, bulk density, and absorption tests were studied. For WPVC replacement, until 30%, compressive strength and flexure strength are acceptable with respect to standerds. Thermal treatment at 200 °C improves the compressive strength, flexure strength and water absorption for 20% WPVC only. The dielectric properties of all cement paste mixes before and after heat treatment, over a frequency range (0.1-106 Hz), were measured as a function of frequency. For dielectric properties and conductivity, an improvement was obtained until 30% WPVC. After this percentage, the dielectric properties and the conductivity got worse. So, cement paste with 30% WPVC as replacement of sand is the optimum ratio with conductivity in range of 10-12 S/cm, which is a good choice for antistatic cement paste applications (10-10-10-12 S/cm). The antimicrobial efficacy of the prepared cement samples of WPVC concentrations (0, 20 and 30) % were studied, the number of grown microbial colonies decreased for all the samples compared to control tap water and decreased by introducing WPVC into the cement paste sample. So, it is recommended to use these samples in places that should be carefully shielded from bacterial infections and static electric charge dangers.
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Affiliation(s)
- Abeer Reffaee
- Microwave Physics and Dielectrics Department, National Research Centre, Cairo, Egypt.
| | - Mona Saied
- Microwave Physics and Dielectrics Department, National Research Centre, Cairo, Egypt
| | - Shimaa Farag Hamieda
- Microwave Physics and Dielectrics Department, National Research Centre, Cairo, Egypt
| | - Sh K Amin
- Chemical Engineering and Pilot Plant Department, Engineering and Renewable Energy Research Institute, National Research Centre (NRC), Affiliation ID: 60014618, Giza, Egypt
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Rozza BY, El-Refai DA, Essawy HA, Alian GA. Effect of silanization of poly (urea-formaldehyde) microcapsules on the flexural strength and self-healing efficiency of an experimental self-healing dental resin composite (An in-vitro study). J Mech Behav Biomed Mater 2024; 151:106372. [PMID: 38211500 DOI: 10.1016/j.jmbbm.2024.106372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 01/01/2024] [Accepted: 01/02/2024] [Indexed: 01/13/2024]
Abstract
OBJECTIVES This study investigated the impact of using γ-methacryloxypropyl trimethoxy silane (MPS) for surface silanization of poly (urea-formaldehyde) (PUF) microcapsules which enclose a healing liquid of "triethylene glycol dimethacrylate (TEGDMA) and N,N dihydroxyethyl-p-toluidine (DHEPT)" on some mechanical properties of an experimental dental composite as well as its self-healing efficiency. METHODS Synthesis of PUF microcapsules was done via in situ polymerization, followed by silanization with MPS silane. Silanized and non-silanized microcapsules were incorporated into a composite containing 30% polymer matrix and 70% fillers at different weight percentages (0%, 5%, 7.5% and 10%). The composite strength and elastic modulus were evaluated by Flexural testing. Fracture toughness KIc and self-healing efficiency were assessed by utilizing the "single edge notched beam" method. RESULTS Flexural strength of all groups containing silanized microcapsules was non-significantly different from control group without microcapsules. However, in contrast to control group, all groups containing non-silanized microcapsules displayed considerably decreased flexural strength. Adding silanized and non-silanized microcapsules didn't show a significant change in the KIc-virgin. The silanized microcapsules' groups achieved a self-healing efficiency of about 49-77% recovery in KIc-virgin compared to 38-69% for their non-silanized counterparts. SIGNIFICANCE In order to increase the interfacial adhesion with the polymer matrix, improve the mechanical properties, and increase the efficiency of self-healing of dental resin composite, PUF microcapsules were silanized for the first time in the dental field using MPS silane. This innovative silanized microcapsule-containing self-healing composite may hold promise for repairing the damage caused by restorative cracks and extending their service life.
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Affiliation(s)
- Basma Yahya Rozza
- Biomaterials Department, Faculty of Dentistry, Ain Shams University (ASU), Biomaterials Research Laboratory, Organization of African Unity Street, El-Qobba Bridge, Al Weili, Cairo Governorate (P.O. 11566), Egypt.
| | - Dina Ahmed El-Refai
- Biomaterials Department, Faculty of Dentistry, Ain Shams University (ASU), Biomaterials Research Laboratory, Organization of African Unity Street, El-Qobba Bridge, Al Weili, Cairo Governorate (P.O. 11566), Egypt
| | - Hisham Abdelfattah Essawy
- Department of Polymers and Pigments, National Research Centre (NRC), 33 El Buhouth Street, AD Doqi, Dokki, Cairo Governorate (P.O. 12622), Egypt.
| | - Ghada Atef Alian
- Biomaterials Department, Faculty of Dentistry, Ain Shams University (ASU), Biomaterials Research Laboratory, Organization of African Unity Street, El-Qobba Bridge, Al Weili, Cairo Governorate (P.O. 11566), Egypt
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Sadid-Zadeh R, Lin K, Li R, Nagy K. Fracture strength of screw-retained zirconia crowns assembled on zirconia and titanium implants. J Prosthodont 2024; 33:273-280. [PMID: 36973859 DOI: 10.1111/jopr.13683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 03/04/2023] [Accepted: 03/20/2023] [Indexed: 03/29/2023] Open
Abstract
PURPOSE This in vitro study evaluated the fracture strength of screw-retained zirconia crowns connected to zirconia (Zr) and titanium (Ti) implants after undergoing a simulation of 5 years of clinical use. MATERIALS AND METHODS Forty-eight screw-retained zirconia crowns were fabricated and assembled on four implant systems, with 12 in each group: (1) Zr implant (pure ceramic; Straumann AG) (PZr); (2) Zr implant (NobelPearl; Nobel Biocare) (NPZr); (3) Ti-Zr implant (Bone Level Roxolid; Straumann AG) (RSTiZr); (4) Ti implant (Conical Connection PMC; Nobel Biocare) (NRTi). Crowns were luted to their associated abutments using resin cement and then torqued to their assigned implants at the recommended torque value. Specimens were subjected to dynamic loading for 1,200,000 loading cycles. Fracture strength, measured in Newtons (N), was tested under static compression load using a universal testing machine at an angle of 30°. One-way ANOVA and Tukey's multiple comparisons post hoc test were used to compare the mean fracture values between the groups at a significance level of 0.05. RESULTS The average fracture strengths for the RSTiZr and NRTi groups were 1207 ± 202 and 1073 ± 217 N, respectively, which was significantly (p < 0.0001) higher than the PZr and NPZr groups (712 ± 76 and 571.6 ± 167 N, respectively). However, no significant difference was found between the fracture strength value of RSTiZr and NRTi (p = 0.260) or PZr and NPZr (p = 0.256) groups. CONCLUSIONS Zirconia crowns connected to Zr implants have the potential to withstand the average physiological occlusal forces which occur in the anterior and premolar regions.
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Affiliation(s)
- Ramtin Sadid-Zadeh
- Department of Restorative Dentistry, University at Buffalo School of Dental Medicine, Buffalo, New York, USA
| | - Kevin Lin
- Department of Restorative Dentistry, University at Buffalo School of Dental Medicine, Buffalo, New York, USA
| | - Rui Li
- Department of Restorative Dentistry, University at Buffalo School of Dental Medicine, Buffalo, New York, USA
| | - Katalin Nagy
- Head of Oral Surgery, Faculty of Dentistry, University of Szeged, Szeged, Hungary
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da Silva Rodrigues C, da Silva AC, Sabino CF, de Melo RM, Campos TMB. Borosilicate glass as a surface finishing alternative for improving the mechanical properties of third-generation zirconia. Dent Mater 2024; 40:477-483. [PMID: 38145923 DOI: 10.1016/j.dental.2023.12.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 12/10/2023] [Accepted: 12/11/2023] [Indexed: 12/27/2023]
Abstract
OBJECTIVE This study evaluated the effect of an experimental borosilicate glass on the mechanical and optical behavior of 5Y-PSZ zirconia and comparing it to commercial glaze and as-sintered. METHODS Disc-shaped specimens of a 5Y-PSZ (Zpex Smile) were prepared and sintered (1550 °C, 2 h). The zirconia discs were randomly divided according to the surface treatment: as-sintered (C), commercial glaze (G), and experimental borosilicate glass (SL). Glaze and experimental glass powders were mixed with building liquids and applied to zirconia with a brush. G specimens were fired at 950 °C and SL at 1200 °C. An extended dwell time of 20 min was applied to both groups. Biaxial flexural strength, roughness (Ra and Rz), translucency (TP00), color alteration (ΔE00), Vickers hardness, fracture toughness, residual stresses, and x-ray diffraction analyses were conducted. Statistical analyses were performed with Weibull statistics, Kruskal-Wallis, or ANOVA tests (α = 5%). RESULTS SL yielded the highest flexural strength (799.35 MPa), followed by G (662.34 MPa), and C (485.38 MPa). The fracture origin of SL specimens was in the bulk zirconia, while G and C showed fractures starting at the surface. As-sintered reached the highest fracture toughness and hardness. Glaze and borosilicate glass provided surface compressive stresses. Borosilicate glass application led to phase transformation (t→m). SL and G showed the lowest roughness. TP00 and ΔE00 were similar among groups. SIGNIFICANCE Borosilicate glass improved strength without harming the optical properties of third-generation zirconia. Toughness and roughness provided by the experimental glass were similar to those from commercial glaze.
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Affiliation(s)
- Camila da Silva Rodrigues
- Department of Dental Materials and Prosthodontics, Institute of Science and Technology, São Paulo State University (UNESP), São José dos Campos, SP, Brazil; Graduate Program in Dentistry, Federal University of Pelotas (UFPel), Pelotas, RS, Brazil.
| | - Ana Carolina da Silva
- Department of Dental Materials and Prosthodontics, Institute of Science and Technology, São Paulo State University (UNESP), São José dos Campos, SP, Brazil.
| | - Clarice Ferreira Sabino
- Department of Dental Materials and Prosthodontics, Institute of Science and Technology, São Paulo State University (UNESP), São José dos Campos, SP, Brazil.
| | - Renata Marques de Melo
- Department of Dental Materials and Prosthodontics, Institute of Science and Technology, São Paulo State University (UNESP), São José dos Campos, SP, Brazil.
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Rues S, Herpel C, Ilani A, Schmitt C, Rammelsberg P, Schwindling FS. Effect of firing time and wall thickness on the biaxial flexural strength of 3D-printed zirconia. Dent Mater 2024; 40:484-492. [PMID: 38155019 DOI: 10.1016/j.dental.2023.12.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 12/13/2023] [Accepted: 12/19/2023] [Indexed: 12/30/2023]
Abstract
OBJECTIVES To evaluate the effect of accelerated firing on 3D-printed zirconia. METHODS To check if formulae provided by ISO 6872 can be extended to thin samples, finite element analyses were carried out in advance of fabricating 3-mol% yttria-stabilized tetragonal zirconia polycrystal discs by milling and by 3D-printing. Four groups (n = 38 each) of 3D-printed specimens were produced with two nominal thicknesses (0.6 mm and 1.2 mm) and two firing strategies (long: 51 h, accelerated: 14.5 h). In the milled group (thickness 1.2 mm, n = 30), a standard firing program (9.8 h) was selected. Biaxial flexural strength tests were applied and mean strength, characteristic strength, and Weibull modulus were calculated for each group. Differences were analyzed using Welch ANOVA and Dunnett-T3 post-hoc tests. RESULTS Maximum tensile stresses occurring during biaxial strength testing can be calculated according to ISO 6872 for thin samples with b > 0.3 mm. Variability of measured strengths values was smaller for milled zirconia compared with 3D-printed zirconia. The 1.2-mm-thick 3D-printed samples had significantly decreased strength after accelerated firing than after long firing. However, for the 0.6-mm-thick samples, comparable mean biaxial strength values of about 1000 MPa were measured for both firing protocols. SIGNIFICANCE At the moment, long fabrication time for zirconia restorations is a major drawback of 3D-printing when compared with milling technology. This investigation showed that the strength of 0.6-mm-thick zirconia discs fabricated by 3D-printing was not impaired by accelerated firing. Thus, overnight firing of thin-walled 3D-printed zirconia restorations could be possible.
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Affiliation(s)
- Stefan Rues
- Department of Prosthodontics, Heidelberg University Hospital, Heidelberg, Germany.
| | - Christopher Herpel
- Department of Prosthodontics, Heidelberg University Hospital, Heidelberg, Germany
| | - Ali Ilani
- Department of Prosthodontics, Heidelberg University Hospital, Heidelberg, Germany
| | - Clemens Schmitt
- Department of Prosthodontics, Heidelberg University Hospital, Heidelberg, Germany; Department of Prosthetic Dentistry, Medical University Innsbruck, Innsbruck, Austria
| | - Peter Rammelsberg
- Department of Prosthodontics, Heidelberg University Hospital, Heidelberg, Germany
| | - Franz Sebastian Schwindling
- Department of Prosthodontics, Heidelberg University Hospital, Heidelberg, Germany; Department of Prosthetic Dentistry, Medical University Innsbruck, Innsbruck, Austria
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Ortensi L, Grande F, Testa C, Balma AM, Pedraza R, Mussano F, La Rosa GRM, Pedullà E. Fracture strength of 3-units fixed partial dentures fabricated with metal-ceramic, graphene doped PMMA and PMMA before and after ageing: An in-vitro study. J Dent 2024; 142:104865. [PMID: 38311017 DOI: 10.1016/j.jdent.2024.104865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 01/13/2024] [Accepted: 01/25/2024] [Indexed: 02/06/2024] Open
Abstract
OBJECTIVES To evaluate the fracture strength and linear elongation at break of three-units fixed partial dentures (FPDs) fabricated with traditional and new materials for fixed prosthodontics before and after ageing. METHODS Sixty models of three-units FPDs were fabricated and cemented onto a Co-Cr model simulating the replacement of a maxillary second premolar. The samples were randomly divided into 3 groups: metal-ceramic (MCR), graphene-doped polymethylmethacrylate (PMMA-GR) and polymethylmethacrylate (PMMA). Half of the samples were directly subjected to fracture test, while the remaining half underwent an ageing process and then a fracture loading test using an electrodynamic testing machine. Fracture load and elongation at break values were taken and statistically analysed. RESULTS Significant differences were detected between the different materials (p<0.05). All groups showed a reduction of the fracture load and elongation at break values after ageing, but not statistically significant, except for PMMA group (p = 2.012e-19) (p = 3.8e-11). CONCLUSIONS MCR and PMMA-GR three-units FPDs showed higher fracture strength and lower elongation at break compared to PMMA. MCR and PMMA-GR had higher resistance to ageing processes compared to PMMA. CLINICAL SIGNIFICANCE PMMA-GR could be considered a material for long-term provisional restorations as its mechanical behaviour and ageing resistance are more like MCR than PMMA.
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Affiliation(s)
- Luca Ortensi
- Department of Prosthodontics, University of Ferrara, Ferrara, Italy
| | - Francesco Grande
- Department of Prosthodontics, University of Ferrara, Ferrara, Italy; Department of Mechanical and aerospace engineering, Polytechnic University of Turin, Turin, Italy.
| | - Claudia Testa
- Department of General Surgery and Medical- Surgical Specialties, University of Catania, Italy
| | - Alessandro Mosca Balma
- Department of Surgical Sciences, CIR Dental School, University of Turin, 10126 Turin, Italy
| | - Riccardo Pedraza
- Department of Mechanical and aerospace engineering, Polytechnic University of Turin, Turin, Italy; Department of Surgical Sciences, CIR Dental School, University of Turin, 10126 Turin, Italy
| | - Federico Mussano
- Department of Surgical Sciences, CIR Dental School, University of Turin, 10126 Turin, Italy
| | | | - Eugenio Pedullà
- Department of General Surgery and Medical- Surgical Specialties, University of Catania, Italy
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Seibert MN, Gedge JL, Vandewalle KS. Fracture strength of ceramic overlays with immediate dentin sealing and same-day delivery. Gen Dent 2024; 72:23-28. [PMID: 38411482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
Limited research is available evaluating whether the reported in vitro benefit of immediate dentin sealing (IDS)-namely, increased bond strength to tooth structure-can be acquired in the era of same-day (SD) dentistry. The purpose of this study was to compare the fracture strengths of ceramic overlays fabricated with a delayed dentin sealing (DDS) technique or an IDS technique under 1-hour SD or 2-week multiple-day (MD) delivery conditions. Forty extracted, healthy maxillary third molars were prepared for a lithium disilicate overlay restoration and divided into 4 groups of 10 teeth each. In the SD-DDS group, the teeth were prepared and then stored for 1 hour in artificial saliva, and the adhesion protocol (bonding agent and resin cement) was applied at the time of delivery of the ceramic overlay. In the SD-IDS group, the teeth were prepared, the adhesive protocol was applied immediately, and the teeth were stored for 1 hour before delivery of the overlay. The protocols for the MD-DDS and MD-IDS groups were identical to SD-DDS and SD-IDS, respectively, except that the teeth were provisionalized and stored for 2 weeks prior to delivery of the overlay. Specimens were thermocycled and subjected to cyclic functional loading before they were loaded to failure in a universal testing machine using a rod resting on the buccal incline of the palatal cusp. Two-way analysis of variance tests revealed no statistically significant differences in fracture strength between the groups based on dentin sealing (P = 0.331) or delivery time (P = 0.314). The specimens demonstrated 2 fracture types; either a portion of the ceramic cohesively fractured, leaving the tooth intact, or the ceramic and part of the tooth fractured. There were no instances in which the restoration itself delaminated during fracture testing. A Kruskal-Wallis test indicated there were no statistically significant differences in fracture modes between the groups. In this in vitro study, IDS did not provide a significant increase in the fracture strength of overlay restorations compared with DDS, regardless of whether the restorations were delivered the same day or after 2 weeks of storage.
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Park GT, Ko KH, Huh YH, Park CJ, Cho LR. Flexural strength and translucency of barium-silicate-filled resin nanoceramics for additive manufacturing. J ESTHET RESTOR DENT 2024; 36:445-452. [PMID: 37671774 DOI: 10.1111/jerd.13129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 08/20/2023] [Accepted: 08/21/2023] [Indexed: 09/07/2023]
Abstract
OBJECTIVE This in vitro study aimed to evaluate the flexural strength (FS) and translucency parameter (TP) of resin nanoceramics (RNCs) with barium silicate for additive manufacturing. MATERIALS AND METHODS An RNC slurry was prepared by mixing a barium silicate filler and resin monomer. For the FS tests, specimens with three filler contents (0, 50, and 63 wt%) were designed according to ISO6872 for dental ceramics and ISO10477 for dental polymers. These specimens were then formed into discs with thicknesses of 1 and 2 mm for TP measurement. RESULTS In the specimens prepared according to ISO6872, the FS increased significantly depending on the filler content. However, in the case of ISO10477, there was no significant difference between the FSs of the specimens with 0 and 50 wt% filler contents. The increase in thickness affected translucency, and the lowest translucency was obtained at a filler content of 63 wt%. The filler distribution was dense in the specimen with 63 wt% filler and uniform but relatively sparse in the specimen with 50 wt% filler. More voids were observed in the specimen with 63 wt% filler. The thickness and filler content of the specimen affected its TP. The TP of the specimen with 63 wt% filler was similar to that of human enamel. CONCLUSION The FS was significantly higher at a filler content of 63 wt%. The lowest translucency was obtained at a filler content of 63 wt% for all tested thicknesses. CLINICAL SIGNIFICANCE Increasing the filler content was advantageous for the mechanical properties of the RNCs. A high filler content led to low translucency in the RNCs. Therefore, the esthetics of human teeth can be reproduced if layering according to the filler content is performed in areas where esthetic characteristics are required.
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Affiliation(s)
- Geun-Taek Park
- Department of Prosthodontics and Research Institute of Oral Science, College of Dentistry, Gangneung-Wonju National University, Gangneung, Republic of Korea
| | - Kyung-Ho Ko
- Department of Prosthodontics and Research Institute of Oral Science, College of Dentistry, Gangneung-Wonju National University, Gangneung, Republic of Korea
| | - Yoon-Hyuk Huh
- Department of Prosthodontics and Research Institute of Oral Science, College of Dentistry, Gangneung-Wonju National University, Gangneung, Republic of Korea
| | - Chan-Jin Park
- Department of Prosthodontics and Research Institute of Oral Science, College of Dentistry, Gangneung-Wonju National University, Gangneung, Republic of Korea
| | - Lee-Ra Cho
- Department of Prosthodontics and Research Institute of Oral Science, College of Dentistry, Gangneung-Wonju National University, Gangneung, Republic of Korea
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Jurado CA, Sadid-Zadeh R, Watanabe H, Robbins CE, Afrashtehfar KI, Fischer NG, Lee DJ. Effect of incisal preparation design on the fracture strength of monolithic zirconia-reinforced lithium silicate laminate veneers. J Prosthodont 2024; 33:281-287. [PMID: 37014263 DOI: 10.1111/jopr.13689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 02/01/2023] [Accepted: 03/27/2023] [Indexed: 04/05/2023] Open
Abstract
PURPOSE This study aimed to assess the fracture resistance of monolithic zirconia-reinforced lithium silicate laminate veneers (LVs) fabricated on various incisal preparation designs. MATERIALS AND METHODS Sixty maxillary central incisors with various preparation designs were 3D-printed, 15 each, including preparation for: (1) LV with feathered-edge design; (2) LV with butt-joint design; (3) LV with palatal chamfer; and (4) full-coverage crown. Restorations were then designed and manufactured from zirconia-reinforced lithium silicate (ZLS) following the contour of a pre-operation scan. Restorations were bonded to the assigned preparation using resin cement and following the manufacturer's instructions. Specimens were then subjected to 10,000 thermocycles at 5 to 55°C with a dwell time of 30 s. The fracture strength of specimens was then assessed using a universal testing machine at a crosshead speed of 1.0 mm/min. One-way ANOVA and Bonferroni correction multiple comparisons were used to assess the fracture strength differences between the test groups (α = 0.001). Descriptive fractographic analysis of specimens was carried out with scanning electron microscopy images. RESULTS Complete coverage crown and LV with palatal chamfer design had the highest fracture resistance values (781.4 ± 151.4 and 618.2 ± 112.6 N, respectively). Single crown and LV with palatal chamfer had no significant difference in fracture strength (p > 05). LV with feathered-edge and butt-joint designs provided significantly (p < 05) lower fracture resistance than complete coverage crown and LV with palatal chamfer design. CONCLUSION The fracture resistance of chairside milled ZLS veneers was significantly influenced by the incisal preparation designs tested. Within the limitation of this study, when excessive occlusal forces are expected, LV with palatal chamfer display is the most conservative method of fabricating an indirect restoration.
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Affiliation(s)
- Carlos A Jurado
- Department of Prosthodontics, The University of Iowa College of Dentistry and Dental Clinics, Iowa City, Iowa, USA
| | - Ramtin Sadid-Zadeh
- Department of Restorative Dentistry, University of Buffalo School of Dental Medicine, Buffalo, New York, USA
| | - Hidehiko Watanabe
- Department of Restorative Dentistry, Oregon Health and Sciences University School of Dentistry, Portland, Oregon, USA
| | - Craig E Robbins
- Department of Restorative Dentistry, Oregon Health and Sciences University School of Dentistry, Portland, Oregon, USA
| | - Kelvin I Afrashtehfar
- Evidence-Based Practice Unit, Clinical Sciences Department, College of Dentistry, Ajman University, Ajman, United Arab Emirates
- Department of Reconstructive Dentistry and Gerodontology, School of Dental Medicine, University of Bern, Bern, Switzerland
| | - Nicholas G Fischer
- Minnesota Dental Research Center for Biomaterials and Biomechanics, University of Minnesota School of Dentistry, Minneapolis, Minnesota, USA
| | - Damian J Lee
- Division of Restorative and Prosthetic Dentistry, The Ohio State University College of Dentistry, Columbus, Ohio, USA
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Kyung KY, Park JM, Heo SJ, Koak JY, Kim SK, Ahn JS, Yi Y. Comparative analysis of flexural strength of 3D printed and milled 4Y-TZP and 3Y-TZP zirconia. J Prosthet Dent 2024; 131:529.e1-529.e9. [PMID: 38212154 DOI: 10.1016/j.prosdent.2023.12.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 12/20/2023] [Accepted: 12/20/2023] [Indexed: 01/13/2024]
Abstract
STATEMENT OF PROBLEM The mechanical properties of 3 dimensionally (3D) printed zirconia have been reported to be comparable with those of milled zirconia, except for the flexural strength. However, most previous studies tested 3 mol% yttria-stabilized tetragonal zirconia polycrystal (3Y-TZP), making it necessary to study 3D printed zirconia with 4 mol% yttria content (4Y-TZP). PURPOSE The purpose of this in vitro study was to compare the flexural strength of 3D printed 4Y-TZP with 3Y-TZP materials and milled 4Y-TZP. MATERIAL AND METHODS A total of 80 disk specimens (Ø15×1.5 mm) were fabricated and divided into 4 groups (n=20) using the fabrication method and yttria content: milled 3Y-TZP (Katana HT; Kuraray Noritake), 3D printed 3Y-TZP (TZ-3Y-E; Tosoh), milled 4Y-TZP (Katana STML; Kuraray Noritake), and 3D printed 4Y-TZP (3DMAT; Genoss). The biaxial flexural strength was determined with a piston-on-3-ball test (n=15). The flexural strength of each specimen was measured, and the Weibull modulus (m) and characteristic strength (σ0) were estimated from the fracture load distribution. Two intact and fractured specimens were examined with scanning electron microscopy (SEM). The crystalline phase of the specimens in each group was identified through X-ray diffraction (XRD) analysis (n=5). A 1-way ANOVA was used to compare the flexural strength among different groups. Subsequently, pairwise comparisons were conducted with the Tukey post hoc method (α=.05). RESULTS The flexural strength of 3D printed 4Y-TZP was significantly higher than that of milled 4Y-TZP (P<.001). In contrast, the flexural strength of 3D printed 3Y-TZP was significantly lower than that of milled 3Y-TZP (P<.001). X-ray diffraction (XRD) analysis revealed that the tetragonal phase was the dominant phase in all groups, with the identification of some cubic phase peaks. CONCLUSIONS Three dimensionally printed 4Y-TZP showed significantly higher flexural strength than milled 4Y-TZP and exhibited a clinically acceptable flexural strength exceeding 800 MPa.
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Affiliation(s)
- Kyu-Young Kyung
- PhD Candidate, Department of Prosthodontics & Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Republic of Republic of Korea
| | - Ji-Man Park
- Associate Professor, Department of Prosthodontics & Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Republic of Korea.
| | - Seong-Joo Heo
- Professor, Department of Prosthodontics & Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Republic of Korea
| | - Jai-Young Koak
- Professor, Department of Prosthodontics & Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Republic of Korea
| | - Seong-Kyun Kim
- Professor, Department of Prosthodontics & Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Republic of Korea
| | - Jin-Soo Ahn
- Professor, Department of Dental Biomaterials Science & Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Republic of Korea
| | - Yuseung Yi
- Assistant Professor, Department of Prosthodontics & Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Republic of Korea
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Yılmaz D, Çakmak G, Güven ME, Pieralli S, Yoon HI, Revilla-León M, Yilmaz B. Effect of Hydrothermal Aging on the Flexural Strength and Microhardness of Materials Used for Additive or Subtractive Manufacturing of Definitive Restorations. INT J PROSTHODONT 2024; 37:133-141. [PMID: 38498865 DOI: 10.11607/ijp.8847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/20/2024]
Abstract
PURPOSE To evaluate the flexural strength (FS) and microhardness of various CAD/CAM restorative materials intended for definitive use. The effect of hydrothermal aging on the mechanical properties of these materials was also investigated. MATERIALS AND METHODS A total of 210 bar-shaped specimens (17 × 4 × 1.5 mm ± 0.02 mm) were fabricated via either subtractive manufacturing (SM) methods-reinforced composite resin (SM-CR), polymer-infiltrated ceramic network (SM-PICN), fine-structured feldspathic ceramic (SMFC), nanographene-reinforced polymethyl methacrylate (PMMA; SM-GPMMA), PMMAbased resin (SM-PMMA)-or additive manufacturing (AM) methods with urethane acrylate-based resins (AM-UA1 and AM-UA2). Specimens were then divided into two subgroups (nonaged or hydrothermal aging; n = 15). A three-point flexural strength test was performed, and five specimens from the nonaged group were submitted to microhardness testing. Specimens were subjected to 10,000 thermal cycles, and the measurements were repeated. RESULTS Regardless of aging, SM-CR had the highest FS (P < .001), followed by SM-GPMMA (P ≤ .042). In nonaged groups, AM-UA2 had a lower FS than all other materials except SM-FC (P = 1.000). In hydrothermal aging groups, AM specimens had lower FS values than other materials, except SM-PMMA. With regard to microhardness, there was no significant difference found between any of the tested materials (P ≥ .945) in the nonaged and hydrothermal aging groups. CONCLUSIONS The effect of hydrothermal aging on FS varied depending on the type of restorative material. Regardless of aging condition, SM-CR showed the highest FS values, whereas SM-FC had the highest microhardness. Hydrothermal aging had no significant influence on the microhardness of the tested materials.
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Yoon GW, Park EJ. Fracture Strength of Six-Unit Anterior Fixed Provisional Restorations Fabricated Using Various Dental CAD/CAM Systems. INT J PROSTHODONT 2024; 37:49-54. [PMID: 38489220 DOI: 10.11607/ijp.8530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2024]
Abstract
PURPOSE This study compares the fracture strengths of long-span fixed provisional restorations fabricated via digital additive and subtractive methods to those fabricated via conventional heat-processing techniques. MATERIALS AND METHODS A six-unit anterior partial restoration was designed as an anatomical and morphologic structure using a dental CAD/CAM system. The provisional restorations (N = 40) of four different fabrication methods (n = 10 per group) were used for the failure loading test: stereolithography apparatus (SLA), liquid crystal display (LCD), milling (MIL), and heat-processed temporary (HPT). The specimens were subjected to a maximum load-to-fracture test using a universal testing machine, and the representative fracture patterns were observed. Statistical analysis was performed using Shapiro-Wilk, Kruskal-Wallis, Mann-Whitney U, and Bonferroni post hoc tests (P < .05). RESULTS The four groups showed significant differences in fracture strength according to the materials and manufacturing methods used (P < .001, except between SLA and HPT groups). The fracture strengths of MIL and LCD digitally fabricated groups were significantly higher than that of the HPT group (P < .001). CONCLUSIONS The subtractive method is ideal for fabricating long-span fixed provisional restorations for long-term use. Additionally, LCD additive manufacturing technology could soon be a good alternative for restorations.
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Rençber A, Karaman T. Mechanical Properties of Zirconia Materials with Different Translucency: An In Vitro Study. INT J PROSTHODONT 2024; 37:72-79. [PMID: 38381986 DOI: 10.11607/ijp.8164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
PURPOSE To investigate the biaxial flexural strength of zirconia materials with different translucency before and after aging procedures and to evaluate the effects of aging on hardness and surface characteristics. MATERIALS AND METHODS A total of 90 disc-shaped specimens (n = 30 each) were prepared from translucent (Upcera-ST, Upcera Dental), high translucent (Katana HT, Kuraray Noritake), and ultra high translucent (Katana UTML, Kuraray Noritake) zirconia materials to a ø.16 ±1.2 mm thickness. The different translucency discs were then divided into three subgroups; one group was subjected to aging in a chewing simulator (n = 10), one group was aged with thermocycling (n = 10), and one was a control group (n = 10). Biaxial flexural strength, Vickers hardness, and surface characteristics were examined for all discs. The data were analyzed using the Shapiro-Wilk (P = .05), Mann-Whitney U, and Kruskal-Wallis H tests. Fracture strength was determined using biaxial bending strength tests, and Weibull analysis was used to analyze the resulting data. RESULTS A statistically significant difference was found among zirconia materials with different translucency in terms of fracture strength. On average, fracture strength was highest in the Upcera ST group (1,932.87 MPa) and lowest in the Katana UTML group (1,073.6 MPa; P = .001). The results of Weibull analysis showed a statistically similar distribution for all groups. CONCLUSIONS Aging procedures did not cause significant differences in fracture strength and hardness. The fracture strength of the zirconia materials with different translucency was considered acceptable for intraoral use.
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Zenthöfer A, Ilani A, Schmitt C, Rammelsberg P, Hetzler S, Rues S. Biaxial flexural strength of 3D-printed 3Y-TZP zirconia using a novel ceramic printer. Clin Oral Investig 2024; 28:145. [PMID: 38351386 PMCID: PMC10864574 DOI: 10.1007/s00784-024-05533-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 01/29/2024] [Indexed: 02/16/2024]
Abstract
OBJECTIVES To compare the strength and reliability of 3D-printed 3Y-TZP zirconia manufactured with various printing orientations and staining. MATERIALS AND METHODS A total of one-hundred cylindrical zirconia specimens were designed and fabricated using 3D printing and processed according to ISO 6872 standards. Of these specimens, 80 were 3D printed using the new ZIPRO-D (ZD) 3D ceramic printer. In this ZD group, 60 specimens were printed in a vertical orientation and were either stained after debinding (ZD1, x-orientation, n = 20) or not stained (ZD2, x-orientation, n = 20; ZD3, y-orientation, n = 20) and the remaining 20 specimens out of n = 80 were printed in a horizontal orientation (ZD4). Further 20 specimens out of the entire sample N = 100 were printed vertically with the CeraFab7500 3D ceramic printer (LC). All completed specimens were loaded until fracture using a universal testing machine. Biaxial flexural strengths and Weibull parameters were computed for the ZD groups and for the LC group. Group and sub-group effects were evaluated using Welch ANOVA (alpha = 0.05). RESULTS The mean (standard deviation, SD) biaxial flexural strengths of vertically oriented ZD samples with (ZD1) and without (ZD2/ZD3) staining were 811 (197) and 850 (152) MPa, respectively (p > 0.05). The ZD4 (horizontally printed), 1107 (144) MPa, and LC (1238 (327)) MPa samples had higher mean (SD) flexural strengths than the ZD1-3 specimens. No difference was observed between the ZD4 and LC group (p > 0.05). Weibull moduli were between m = 4.6 (ZD1) and 9.1 (ZD4) in the ZD group and m = 3.5 in the LC group. CONCLUSIONS All tested 3D-printed zirconia specimens exceeded the flexural strengths required for class 5 restorations according to ISO 6872 standards. While the flexural strengths of zirconia printed using the novel ZD device in the vertical orientation are lower than those of zirconia printed using the LC printer, the ZD printer shows at least comparable reliability. CLINICAL RELEVANCE 3D-printing of zirconia is a new technology in dental application. Based on the presented strengths values, clinical application of 3D-printed zirconia for fixed dental protheses can be recommended.
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Affiliation(s)
- Andreas Zenthöfer
- Department of Prosthodontics, University Clinic Heidelberg, University of Heidelberg, 69120, Heidelberg, Germany.
| | - Ali Ilani
- Department of Prosthodontics, University Clinic Heidelberg, University of Heidelberg, 69120, Heidelberg, Germany
| | - Clemens Schmitt
- Department of Prosthodontics, University Clinic Heidelberg, University of Heidelberg, 69120, Heidelberg, Germany
| | - Peter Rammelsberg
- Department of Prosthodontics, University Clinic Heidelberg, University of Heidelberg, 69120, Heidelberg, Germany
| | - Sebastian Hetzler
- Department of Prosthodontics, University Clinic Heidelberg, University of Heidelberg, 69120, Heidelberg, Germany
| | - Stefan Rues
- Department of Prosthodontics, University Clinic Heidelberg, University of Heidelberg, 69120, Heidelberg, Germany
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Huang JJ, Jia L, Zhang QJ, Li HH, Zheng DL, Zheng M. Anti-Microbial Effect of AgBr-NP@CTMAB on Streptococcus Mutans and Assessment of Surface Roughness Hardness and Flexural Strength of PMMA. Int J Nanomedicine 2024; 19:1273-1285. [PMID: 38348176 PMCID: PMC10860590 DOI: 10.2147/ijn.s436613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 01/24/2024] [Indexed: 02/15/2024] Open
Abstract
Purpose To investigate the inhibition of Streptococcus mutans (S.mutans) and its biofilm by AgBr-nanoparticles (NP) @CTMAB (cetyltrimethyl-ammonium bromide) and evaluate the changes in Polymethyl methacrylate (PMMA)'s surface roughness (Ra), microhardness, and flexural strength during prolonged immersion in AgBr-NP@CTMAB for application in the denture cleaning industry. Patients and Methods The antibacterial activity of AgBr-NP@CTMAB against S.mutans was measured colony formation assay, OD600 and laser confocal microscopy. Changes in the specimens' values for surface roughness, microhardness, and flexural strength (MPa) were measured after immersion solutions for 180 or 360 days. Results The AgBr-NP@CTMAB solution exhibited a robust antibacterial effect on planktonic S. mutans, with a minimum bactericidal concentration of 5 µg/mL. The 10 µg/mL AgBr-NP@CTMAB solution efficiently inhibited S. mutans biofilm formation. (2) No significant difference in surface roughness after immersion in AgBr-NP@CTMAB (10 µg/mL and 20 µg/mL) comparing with distilled water (P > 0.05) and Polident had significantly higher than distilled water (P < 0.05). There was a significant decrease in the surface hardness of the PMMA specimens that were immersed in the Polident compared with those in distilled water (P < 0.05). While, no significant differences in surface hardness after immersion in the AgBr-NP@CTMAB (P > 0.05). The result of flexural strength suggested that there was no statistically significant difference (P < 0.05) between AgBr-NP@CTMAB as well as Polident and water. Conclusion AgBrNP@CTMAB can efficiently inhibit the growth of plankton S.mutans and biofilm formation, without affecting the flexural strength, microhardness, or surface roughness of PMMA. Therefore, AgBrNP@CTMAB holds promise as a new denture cleaning agent.
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Affiliation(s)
- Jing-Jing Huang
- Second Department of Dental Implant, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, 350001, People’s Republic of China
| | - Lin Jia
- Fujian Key Laboratory of Oral Diseases, Fujian Biological Materials Engineering and Technology Center of Stomatology, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, Fujian, 350004, People’s Republic of China
- Department of Prosthodontics, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, 350001, People’s Republic of China
| | - Qiao-Jun Zhang
- Zhongshan Hospital Affiliated to Xiamen University, Xiamen, 361000, People’s Republic of China
| | - Hao-Hong Li
- College of Chemistry, Fuzhou University, Fuzhou, Fujian, 350116, People’s Republic of China
| | - Da-Li Zheng
- Fujian Key Laboratory of Oral Diseases, Fujian Biological Materials Engineering and Technology Center of Stomatology, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, Fujian, 350004, People’s Republic of China
| | - Ming Zheng
- Department of Prosthodontics, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, 350001, People’s Republic of China
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Marcomini N, Albaricci MCDC, Costa JLDSG, Besegato JF, Godoy EF, Dantas AAR, Kuga MC. Effects of alpha-tocopherol antioxidant on fracture strength and adhesion of endodontically treated teeth restored after dental bleaching. Eur J Oral Sci 2024; 132:e12965. [PMID: 38115770 DOI: 10.1111/eos.12965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 11/14/2023] [Indexed: 12/21/2023]
Abstract
This study evaluated the effect of different concentrations of alpha-tocopherol in gel form on fracture strength, hybrid layer formation, and microtensile bond strength of endodontically treated teeth bleached with 40% hydrogen peroxide (H2 O2 ). Sixty bovine incisors were randomized into one of six groups (n = 10 incisors per group) defined by the interventions carried out after endodontic treatment. In the control group, no additional intervention was carried out, while all teeth in the five intervention groups were bleached with 40% H2 O2 and subsequently treated with alpha-tocopherol at concentrations of 15% (15AT), 20% (20AT), or 25% (25AT), with 10% sodium ascorbate (10SA), or with nothing (40HP). Fracture strength was evaluated in a mechanical testing machine, hybrid layer formation was assessed using scanning electron microscopy, and bond strength was determined using microtensile bond-strength testing. Data were analyzed using Kruskal-Wallis and Dunn's tests. No statistically significant difference regarding fracture strength was observed among groups. Hybrid layer formation was greater in the 15AT group than in groups 40HP and 10SA. Teeth in groups 15AT, 20AT, and 25AT demonstrated higher bond strength than teeth in groups 40HP and 10SA. Alpha-tocopherol, preferably at 15%, effectively reverses the deleterious effects, of bleaching, on hybrid layer formation and bond strength to dentin.
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Affiliation(s)
- Natália Marcomini
- Department of Restorative Dentistry, School of Dentistry, Araraquara, São Paulo State University - UNESP, Araraquara, São Paulo, Brazil
| | - Maria Carolina da Costa Albaricci
- Department of Restorative Dentistry, School of Dentistry, Araraquara, São Paulo State University - UNESP, Araraquara, São Paulo, Brazil
| | - Joatan Lucas de Sousa Gomes Costa
- Department of Restorative Dentistry, School of Dentistry, Araraquara, São Paulo State University - UNESP, Araraquara, São Paulo, Brazil
- Department of Restorative Dentistry, School of Dentistry, Federal University of Minas Gerais - UFMG, Belo Horizonte, Minas Gerais, Brazil
| | - João Felipe Besegato
- School of Dentistry, Federal University of Mato Grosso do Sul - UFMS, Campo Grande, Mato Grosso do Sul, Brazil
| | | | - Andréa Abi Rached Dantas
- Department of Restorative Dentistry, School of Dentistry, Araraquara, São Paulo State University - UNESP, Araraquara, São Paulo, Brazil
| | - Milton Carlos Kuga
- Department of Restorative Dentistry, School of Dentistry, Araraquara, São Paulo State University - UNESP, Araraquara, São Paulo, Brazil
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Campos TMB, Dos Santos C, Alves LMM, Benalcazar-Jalkh EB, Strazzi-Sahyon HB, Bergamo ETP, Tebcherani SM, Witek L, Coelho PG, Yamaguchi S, Thim GP, Bonfante EA. Minimally processed recycled yttria-stabilized tetragonal zirconia for dental applications: Effect of sintering temperature on glass infiltration. J Mech Behav Biomed Mater 2024; 150:106311. [PMID: 38128470 DOI: 10.1016/j.jmbbm.2023.106311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2023] [Revised: 12/03/2023] [Accepted: 12/04/2023] [Indexed: 12/23/2023]
Abstract
This study aimed to develop a recycling process for the remnants of milled 3Y-TZP and enhance their properties using glass infiltration. 3Y-TZP powder was gathered from the vacuum system of CAD-CAM milling equipment, calcined and sieved (x < 75 μm). One hundred twenty discs were fabricated and pre-sintered at 1000 °C/h. These specimens were then divided into four groups, categorized by glass infiltration (non-infiltrated [Zr] or glass-infiltrated [Zr-G]) and sintering temperature (1450 °C [Zr-1450] or 1550 °C [Zr-1550]/2h). After sintering, the specimens were characterized by X-Ray Diffraction (XRD), relative density measurement, and scanning electron microscopy and energy dispersive spectroscopy (SEM-EDS). The biaxial flexural strength test was performed according to the ISO 6872 and followed by fractographic analysis. Subsequent results were analyzed using Weibull statistics. Relative density values of the sintered specimens from Zr-1450 and Zr-1550 groups were 86.7 ± 1.5% and 92.2 ± 1.7%, respectively. Particle size distribution revealed particles within the range of 0.1-100 μm. XRD analysis highlighted the presence of the ZrO2-tetragonal in both the Zr-1450 and Zr-1550 groups. Glass infiltration, however, led to the formation of the ZrO2-monoclinic of 9.84% (Zr-1450-G) and 18.34% (Zr-1550-G). SEM micrographs demonstrated similar microstructural characteristics for Zr-1450 and Zr-1550, whereas the glass-infiltrated groups exhibited comparable infiltration patterns. The highest characteristic strength was observed in the glass-infiltrated groups. Fractographic analyses suggested that fracture origins were related to defects on the tensile side, which propagated to the compression side of the samples. Both the sintering temperature and glass infiltration significantly influenced the mechanical properties of the 3Y-TZP recycled.
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Affiliation(s)
- Tiago Moreira Bastos Campos
- Department of Prosthodontics and Periodontology, University of São Paulo - Bauru School of Dentistry, Bauru, SP, Brazil
| | - Claudinei Dos Santos
- Faculty of Technology, University of Rio de Janeiro State (UERJ - FAT), Resende, RJ, Brazil
| | - Larissa Marcia Martins Alves
- Department of Prosthodontics and Periodontology, University of São Paulo - Bauru School of Dentistry, Bauru, SP, Brazil.
| | - Ernesto B Benalcazar-Jalkh
- Department of Prosthodontics and Periodontology, University of São Paulo - Bauru School of Dentistry, Bauru, SP, Brazil
| | | | - Edmara T P Bergamo
- Department of Prosthodontics and Periodontology, University of São Paulo - Bauru School of Dentistry, Bauru, SP, Brazil; Biomaterials Division, New York University College of Dentistry, New York, NY, USA
| | - Sérgio Mazurek Tebcherani
- Department of Production Engineering, Federal University of Technology, Paraná, Ponta Grossa, PR, Brazil
| | - Lukasz Witek
- Biomaterials Division, New York University College of Dentistry, New York, NY, USA; Department of Biomedical Engineering, NYU Tandon School of Engineering, New York University, Brooklyn, NY, USA
| | - Paulo G Coelho
- Division of Plastic Surgery, Department of Surgery, University of Miami Miller School of Medicine, Miami, FL, USA; Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Satoshi Yamaguchi
- Department of Dental Biomaterials, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan
| | - Gilmar P Thim
- Department of Physics, Aeronautics Technological Institute, São José Dos Campos, SP, Brazil
| | - Estevam A Bonfante
- Department of Prosthodontics and Periodontology, University of São Paulo - Bauru School of Dentistry, Bauru, SP, Brazil
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Nakade P, Thaore S, Bangar B, Grover I, Alharethi N, Adsure G, Kulkarni D. Comparative Evaluation of Fracture Toughness and Flexural Strength of Four Different Core Build-up Materials: An In Vitro Study. J Contemp Dent Pract 2024; 25:191-195. [PMID: 38514419 DOI: 10.5005/jp-journals-10024-3624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2024]
Abstract
AIM To evaluate and compare the fracture toughness and flexural strength of four different core build-up materials. MATERIALS AND METHODS A total of 60 samples were divided into four groups (n = 15) group I: dual cure composite resin reinforced with zirconia particles (Luxacore Z), group II: light cure composite resin (Lumiglass DeepCure), group III: zirconia reinforced glass ionomer cement (GIC) (Zirconomer Improved), and group IV: chemically cure composite resin (Self Comp) respectively. All the core build-up materials were manipulated according to the manufacturer's instructions and poured into the mold. A universal testing machine applied a central load to the specimen in a 3-point bending mode. Fracture of the specimen was identified and the reading was recorded by the universal testing machine. The data were analyzed statistically using one-way analysis of variance (ANOVA) and then compared. RESULTS Group I showed the highest flexural strength (48.65 MPa) among all the groups while group IV showed the lowest flexural strength (17.90 MPa). Group I showed the highest fracture toughness (99.12 MPa) among all the groups while group IV showed the lowest fracture toughness (36.41 MPa.cm-0.5). When mean flexural strength and fracture toughness values of all four groups were compared by using one-way ANOVA, the compared data was highly significant. CONCLUSION Based on the findings of this study, dual cure composite resin was the material of choice in terms of flexural strength and fracture toughness for core build-up material followed by light cure composite resin. CLINICAL SIGNIFICANCE The core buildup material serves to strengthen the tooth structure, allowing it to withstand the forces of chewing and preventing the risk of tooth fractures. This material is essential in restoring damaged or decayed teeth, as it provides a stable foundation for further dental work. By reinforcing the tooth structure, the core buildup material ensures that the tooth can function properly and remain healthy for years to come. How to cite this article: Nakade P, Thaore S, Bangar B, et al. Comparative Evaluation of Fracture Toughness and Flexural Strength of Four Different Core Build-up Materials: An In Vitro Study. J Contemp Dent Pract 2024;25(2):191-195.
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Affiliation(s)
- Prashant Nakade
- Department of Prosthodontics, M.A. Rangoonwala College of Dental Sciences & Research Centre, Pune, Maharashtra, India, Phone: +91 9890355908, e-mail:
| | - Sonam Thaore
- Department of Conservative Dentistry and Endodontics, SMBT Dental College & Hospital, Sangamner, Maharashtra, India
| | - Bhushan Bangar
- Department of Prosthodontics, MIDSR Dental College and Hospital, Latur, Maharashtra, India
| | - Ishita Grover
- Department of Prosthodontics, M.A. Rangoonwala College of Dental Sciences & Research Centre, Pune, Maharashtra, India
| | - Naji Alharethi
- Department of Prosthodontic Sciences, College of Dentistry, Qassim University, Ar Rass, Saudi Arabia
| | - Girija Adsure
- Department of Orthodontics and Dentofacial Orthopedics, M.A. Rangoonwala College of Dental Sciences & Research Centre, Pune, Maharashtra, India
| | - Dinraj Kulkarni
- Department of Oral Pathology and Microbiology, M.A. Rangoonwala College of Dental Sciences & Research Centre, Pune, Maharashtra, India
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Sadek HMA, El-Banna A. Biaxial flexural strength of different provisional restorative materials under chemo-mechanical aging: An in vitro study. J Prosthodont 2024; 33:149-156. [PMID: 36738226 DOI: 10.1111/jopr.13662] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Revised: 01/22/2023] [Accepted: 01/24/2023] [Indexed: 02/05/2023] Open
Abstract
PURPOSE Durability is a critical factor for the success of long-term provisional restorations. This study evaluated the effect of different storage media and cyclic loading on the biaxial flexural strength of different types of provisional materials. MATERIALS AND METHODS Discs (N = 360, 10 × 2 mm) were prepared from different provisional materials; conventional (Protemp 4, Tuff-Temp, Tempron), CAD-CAM milled (VITA CAD-Temp, breCAM.multiCOM), and 3D-printed (Nextdent C&B MFH) (n = 60). Each material group was subdivided into four subgroups according to the storage media (n = 15): nonaged, artificial saliva, mouthwash, and coffee. The specimens in storage media were placed in an incubator at 37°C for 4 weeks followed by 60,000 simulated chewing cycles. Biaxial flexural strength test was done. Data were analyzed using two-way ANOVA. Weibull distribution parameters were estimated. RESULTS Both the material and aging protocol showed a significant effect on the biaxial flexural strength. Both Protemp 4 and Nextdent C&B MFH showed a significantly higher biaxial flexural strength before and after aging compared to all other materials. Protemp 4 and Tuff Temp showed a significant decrease in strength with aging. CAD-CAM materials showed higher Weibull moduli. CONCLUSIONS The 3D-printed polymethylmethacrylate provisional material presents with both greater biaxial flexural strength and increased durability against chemical and mechanical aging compared to conventional and CAD-CAM milled provisional materials tested.
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Affiliation(s)
- Hoda M Abdel Sadek
- Department of Fixed Prosthodontics, Faculty of Dentistry, Ain Shams University, Cairo, Egypt
| | - Ahmed El-Banna
- Department of Dental Biomaterials, Faculty of Dentistry, Ain Shams University, Cairo, Egypt
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Prause E, Malgaj T, Kocjan A, Beuer F, Hey J, Jevnikar P, Schmidt F. Mechanical properties of 3D-printed and milled composite resins for definitive restorations: An in vitro comparison of initial strength and fatigue behavior. J ESTHET RESTOR DENT 2024; 36:391-401. [PMID: 37680013 DOI: 10.1111/jerd.13132] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Revised: 08/06/2023] [Accepted: 08/25/2023] [Indexed: 09/09/2023]
Abstract
OBJECTIVE To evaluate the flexural strength and fatigue behavior of a novel 3D-printed composite resin for definitive restorations. MATERIALS AND METHODS Fifty disc-shaped specimens were manufactured from each of a nanohybrid composite resin (NHC), polymer-infiltrated ceramic network (PICN), and 3D-printed composite resin (3D) with CAD-CAM technology. Biaxial flexural strength (σin ) (n = 30 per group) and biaxial flexural fatigue strength (σff ) (n = 20 per group) were measured using piston-on-three-balls method, employing a staircase approach of 105 cycles. Weibull statistics, relative-strength degradation calculations, and fractography were performed. The results were analyzed with 1-way ANOVA and Games-Howell post hoc test (α = 0.05). RESULTS Significant differences in σin and σff among the groups (p < 0.001) were detected. The NHC group provided the highest mean ± standard deviation σin and σff (237.3 ± 31.6 MPa and 141.3 ± 3.8 MPa), followed by the PICN (140.3 ± 12.9 MPa and 73.5 ± 9.9 MPa) and the 3D (83.6 ± 18.5 MPa and 37.4 ± 23.8 MPa) groups. The 3D group exhibited significantly lower Weibull modulus (m = 4.7) and up to 15% higher relative strength degradation with areas of nonhomogeneous microstructure as possible fracture origins. CONCLUSIONS The 3D-printed composite resin exhibited the lowest mechanical properties, where areas of nonhomogeneous microstructure developed during the mixing procedure served as potential fracture origins. CLINICAL SIGNIFICANCE The clinical indications of the investigated novel 3D-printed composite resin should be limited to long-term provisional restorations. A cautious procedure for mixing the components is crucial before the 3D-printing process, since nonhomogeneous areas developed during the mixing could act as fracture origins.
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Affiliation(s)
- Elisabeth Prause
- Department of Prosthodontics, Geriatric Dentistry and Craniomandibular Disorders, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Tine Malgaj
- Department of Prosthodontics, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Andraž Kocjan
- Department for Nanostructured Materials, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Florian Beuer
- Department of Prosthodontics, Geriatric Dentistry and Craniomandibular Disorders, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Jeremias Hey
- Department of Prosthodontics, School of Dental Medicine, Martin-Luther-University, Halle, Germany
| | - Peter Jevnikar
- Department of Prosthodontics, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Franziska Schmidt
- Department of Prosthodontics, Geriatric Dentistry and Craniomandibular Disorders, Charité-Universitätsmedizin Berlin, Berlin, Germany
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Thomas HA, Singh N, Thomas AM, Masih S, Cherian JM, Varghese KG. Effect of protective coating agents on microleakage and flexural strength of glass ionomer cement and zirconomer. an in vitro study. Eur Arch Paediatr Dent 2024; 25:57-63. [PMID: 37991624 DOI: 10.1007/s40368-023-00853-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 10/25/2023] [Indexed: 11/23/2023]
Abstract
PURPOSE The objective of this study was to assess the microleakage and flexural strength of glass ionomer cement (GIC) and modified GIC (Zirconomer) when coated with protective coating agents such as COAT-IT and G-COAT plus. METHODS Sixty tooth specimens were grouped into two groups based on the type of restorations (GIC (n = 30) and Zirconomer (n = 30)). The samples were further divided into three subgroups (n = 10) based on the protective coating agent (Petroleum jelly, G-COAT Plus, or COAT IT) applied. This study evaluated the microleakage at the occlusal and cervical margins of class V restoration after being subjected to dye penetration and sectioning. Each specimen was viewed under a 40 × microscope and was given scores based on the depth of dye penetration. They were statistically analyzed using the Kruskal-Wallis test and compared within the groups using the Mann- Whitney Test. In addition, flexural strength was assessed using standardized cuboid (25 × 2 × 2 mm) specimens of restorative materials with and without protective coating agents. The mean flexural strength data of all the subgroups were statistically evaluated using a one-way analysis of variance (ANOVA) and compared within the subgroups using the student t test. RESULTS A statistically significant difference was found when occlusal margin microleakage scores were evaluated with G-COAT Plus demonstrating the lowest occlusal margin microleakage when applied over GIC restoration. The increasing order of occlusal margin microleakage scores is as follows: GIC with G-COAT Plus, Zirconomer with COAT-IT, GIC with COAT-IT, GIC, Zirconomer with G-COAT Plus, and Zirconomer. However, the cervical margin microleakage scores revealed no significant difference. While flexural strength was found to be highest for the GIC group coated with G-COAT Plus, it was observed that there was a significant improvement in the flexural strength of both GIC and Zirconomer when coated with either of the protective coating agents. CONCLUSION Within the limitations of this in vitro study, it was observed that the application of protective coating agents can significantly reduce the potential microleakage and improve the flexural strength of the restorative material especially when zirconia-reinforced GIC is the restorative material.
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Affiliation(s)
- H A Thomas
- Department of Pedodontics and Preventive Dentistry, Christian Dental College, Ludhiana, Punjab, India.
| | - N Singh
- Department of Pedodontics and Preventive Dentistry, Christian Dental College, Ludhiana, Punjab, India
| | - A M Thomas
- Department of Pedodontics and Preventive Dentistry, Christian Dental College, Ludhiana, Punjab, India
| | - S Masih
- Department of Pedodontics and Preventive Dentistry, Christian Dental College, Ludhiana, Punjab, India
| | - J M Cherian
- Department of Pedodontics and Preventive Dentistry, Christian Dental College, Ludhiana, Punjab, India
| | - K G Varghese
- Department of Prosthodontics and Crown and Bridge, Christian Dental College, Ludhiana, Punjab, India
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da Costa Ward PA, Ward F, Alves MFRP, Moreira da Silva CR, Moreira LP, Santos CD. Numerical analysis of the mechanical behavior of ceramic dental implants based on Ce-TZP/Al 2O 3 composite. J Mech Behav Biomed Mater 2024; 150:106335. [PMID: 38150817 DOI: 10.1016/j.jmbbm.2023.106335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 12/11/2023] [Accepted: 12/16/2023] [Indexed: 12/29/2023]
Abstract
This study aimed to identify the potential use of the ceramic composite ZrO2(CeO2)-Al2O3 as a dental implant due to its intrinsic geometry and different masticatory loads based on finite element simulations. Ceramic samples were sintered at 1500 °C-2h, and characterized: The mechanical properties of the ceramic composite (hardness, fracture toughness, flexural strength, Young's Modulus, and Poisson ratio) were determined, in addition to the relative density and its structural characteristics. Commercial dental implant designs (incisal and third-molar) on CAD models were used in this study as an initial implant geometry applied in a typical simulated mandible anatomy. Finite element models were generated for implant geometries using CAD and CAE techniques. Loading cases were considered based on different intensities (100-500 N) and orientation angles to the implant axis (0° and 45°) to reproduce human masticatory conditions. For comparison purposes, the numerical predictions were compared with finite element simulations of gold-standard titanium implants. Ce-TZP/Al2O3 sintered ceramics showed flexural strength of 952.6 ± 88 MPa, hardness and fracture toughness of 1427 ± 46 HV and 11.3 ± 0.4 MPa m1/2, respectively, beside Young's modulus of 228.3 ± 65 GPa and Poisson ratio of 0.28. For both Ce-TZP/Al2O3 dental implant geometries, the implant prototypes showed adequate mechanical behavior regardless of the masticatory load value or the orientation angle applied in the simulations: All finite element predictions are lower than the values established by Mohr Coulomb's failure criterion, allowing the feasibility, preliminarily, of the proposed ceramics for dental implant applications without fracture risk.
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Affiliation(s)
- Pedro Araújo da Costa Ward
- Universidade Federal Fluminense - Escola de Engenharia Industrial Metalúrgica de Volta Redonda - UFF/EEIMVR, Av. dos Trabalhadores, 420, Vila Santa Cecília, 27.255-125, Volta Redonda-RJ, Brazil
| | - Fernando Ward
- Universidade Federal Fluminense - Escola de Engenharia Industrial Metalúrgica de Volta Redonda - UFF/EEIMVR, Av. dos Trabalhadores, 420, Vila Santa Cecília, 27.255-125, Volta Redonda-RJ, Brazil
| | - Manuel Fellipe Rodrigues Pais Alves
- Universidade do Estado do Rio de Janeiro - Faculdade de Tecnologia de Resende UERJ/FAT, Rodovia Presidente Dutra, Km 298, 27.537-000, Resende-RJ, Brazil
| | | | - Luciano Pessanha Moreira
- Universidade Federal Fluminense - Escola de Engenharia Industrial Metalúrgica de Volta Redonda - UFF/EEIMVR, Av. dos Trabalhadores, 420, Vila Santa Cecília, 27.255-125, Volta Redonda-RJ, Brazil
| | - Claudinei Dos Santos
- Universidade Federal Fluminense - Escola de Engenharia Industrial Metalúrgica de Volta Redonda - UFF/EEIMVR, Av. dos Trabalhadores, 420, Vila Santa Cecília, 27.255-125, Volta Redonda-RJ, Brazil; Universidade do Estado do Rio de Janeiro - Faculdade de Tecnologia de Resende UERJ/FAT, Rodovia Presidente Dutra, Km 298, 27.537-000, Resende-RJ, Brazil.
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Geiger V, Mayinger F, Hoffmann M, Reymus M, Stawarczyk B. Fracture toughness, work of fracture, flexural strength and elastic modulus of 3D-printed denture base resins in two measurement environments after artificial aging. J Mech Behav Biomed Mater 2024; 150:106234. [PMID: 37995602 DOI: 10.1016/j.jmbbm.2023.106234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 11/05/2023] [Accepted: 11/07/2023] [Indexed: 11/25/2023]
Abstract
OBJECTIVES To investigate the fracture toughness (KIC), work of fracture (WOF), flexural strength (FS) and elastic modulus (E) of four additively manufactured denture base resins in two different measurement environments after artificial aging. METHODS Rectangular specimens in two different dimensions (n = 480) were 3D-printed with four denture base resins: Denture 3D+ (DEN; NextDent), Fotodent Denture (FOT; Dreve ProDiMed), Freeprint Denture (FRE; Detax), V-Print dentbase (VPR; VOCO)). KIC, WOF, FS and E were measured after (1) water-storage (37 °C; KIC = 7 d; FS = 50 h); (2) water-storage + hydrothermal-aging (20 min, 0.2 MPa, 134 °C); (3) water storage + thermocycling (10,000 cycles, 5/55 °C) in two measurement environments (i) air-23 °C and (ii) water-37 °C. For FS, fracture types were classified, and relative frequencies determined. Univariate ANOVA, Kruskal-Wallis, Mann-Whitney U, and Spearman's correlation were calculated (p < 0.05, SPSS V.27.0). Weibull modulus (m) was calculated using the maximum likelihood estimation method. RESULTS DEN showed the highest KIC (5/6 groups), WOF and highest corresponding m (1/6 groups), while FRE presented the highest FS (2/6 groups) and E values. Hydrothermal-aging and thermocycling reduced KIC and WOF, FS and E, and the number of FS fracture pieces. For 6/8 groups, hydrothermal aging resulted in lower FS than thermocycling. Measurement in air-23 °C led to higher FS for 7/12 groups and a more brittle fracture behavior. A positive correlation between KIC and FS was observed. SIGNIFICANCE With measurements in air-23 °C resulting in higher FS than reported in water-37 °C, the measurement environment should be adapted to the clinical situation to allow valid predictions on the mechanical behavior of denture base resins when in situ.
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Affiliation(s)
- Veronika Geiger
- Department of Prosthetic Dentistry, Dental School, LMU Munich, Goethestraße 70, 80336, Munich, Germany.
| | - Felicitas Mayinger
- Department of Prosthetic Dentistry, Dental School, LMU Munich, Goethestraße 70, 80336, Munich, Germany
| | - Moritz Hoffmann
- Department of Prosthetic Dentistry, Dental School, LMU Munich, Goethestraße 70, 80336, Munich, Germany
| | - Marcel Reymus
- Department of Conservative Dentistry and Periodontology, Dental School, LMU Munich, Goethestraße 70, 80336, Munich, Germany
| | - Bogna Stawarczyk
- Department of Prosthetic Dentistry, Dental School, LMU Munich, Goethestraße 70, 80336, Munich, Germany
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Alghazzawi TF, Janowski GM, Eberhardt AW. An experimental study of flexural strength and hardness of zirconia and their relation to crown failure loads. J Prosthet Dent 2024; 131:320-328. [PMID: 35995603 DOI: 10.1016/j.prosdent.2022.04.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 04/04/2022] [Accepted: 04/05/2022] [Indexed: 11/23/2022]
Abstract
STATEMENT OF PROBLEM Dental zirconia is often marketed and selected for restorative use based upon the biaxial flexural strength of prefabricated specimens (disks) without considering other mechanical and physical properties. PURPOSE The purpose of this in vitro study was to test whether 4-point flexural strength, biaxial flexural strength, and/or hardness may correlate with failure loads for crowns made of different zirconia materials. MATERIAL AND METHODS Three brands of zirconia (BruxZir, Cercon, and Katana) were used to fabricate anatomically contoured crowns, rectangular bars, and circular disks. The sample size was n=15 specimens per zirconia brand and specimen shape. The bars were tested for 4-point flexural strength by using the 4-point bending (4PB) test and Vickers hardness (VH), while the disks were tested for biaxial flexural strength by using a piston-on-3 ball (POB) test. Crowns were attached to resin abutments and compressed with a steel spherical indenter through a polyethylene sheet to assess the failure loads by using the "crunch the crown" (CTC) test. One-way ANOVA (α=.05) was used to test for statistically significant differences between groups, and Weibull analysis was used to assess the variability of the measured flexural strengths, failure load, and hardness. RESULTS Statistical differences (P<.001) were found in comparing Cercon, BruxZir, and Katana ([4260 N=4186 N]>3195 N, respectively) with the CTC test and (396 MPa>[281 MPa=275 MPa], respectively) the 4PB test. No statistical differences (P=.084) were found among the zirconia brands (Cercon [384 MPa]=Bruxzir [359 MPa]=Katana [416 MPa]) for the POB test. No significant correlations (P>.05) were found between the 4PB, POB, or VH tests and the corresponding CTC test. The Weibull modulus varied for the different specimen geometries. CONCLUSIONS The piston-on-3 ball, 4-point bending, and Vickers hardness test results were not correlated with the corresponding crunch-the-crown test.
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Affiliation(s)
- Tariq F Alghazzawi
- Associate Professor, Department of Substitutive Dental Sciences, Taibah University, Madina, Saudi Arabia; Fullbright Scholar, Department of Materials Science and Engineering, The University of Alabama at Birmingham, Birmingham, USA.
| | - Gregg M Janowski
- Professor, Department of Materials Science and Engineering, University of Alabama at Birmingham, Birmingham, Ala
| | - Alan W Eberhardt
- Professor and Associate Chair, Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, Ala
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Hamdy TM. Evaluation of flexural strength, impact strength, and surface microhardness of self-cured acrylic resin reinforced with silver-doped carbon nanotubes. BMC Oral Health 2024; 24:151. [PMID: 38297290 PMCID: PMC10832083 DOI: 10.1186/s12903-024-03909-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 01/17/2024] [Indexed: 02/02/2024] Open
Abstract
BACKGROUND Poly-methyl methacrylate (PMMA) is a type of polymer mostly used to make denture bases. Self-cured acrylic resin (PMMA) can be used to repair a fractured acrylic denture base; however, even after repair, this area remains vulnerable. Carbon nanotubes (CNTs) could be used as a filler for polymer reinforcement. Furthermore, silver nanoparticles are efficient agents for the prevention of dental biofilm and improving their mechanical properties. The doping of CNTs with silver nanoparticles may lead to a synergistic interaction that is predicted to enhance the mechanical characteristics of the fillers. OBJECTIVES The aim of the study was to assess the influnce of manual incorporation of 0.5% weight percent (%wt.) of silver doped carbon nanotubes (Ag-doped CNTs) into commercial self-cured PMMA on its flexural strength, impact strength, and surface microhardness. METHODS In this investigation, a total of 60 specimens comprised of acrylic resin were employed. They are divided into two main groups: (a) the control group, which was made by using liquid monomer and commercial self-cured PMMA powder; and (b) the modified group, prepared by hand mixing the purchased silver-doped CNTs powder (0.5% wt.) to self-cured PMMA powder (99.5%wt.), and then the blended powder was incorporated into the liquid monomer. Flexural strength, flexural modulus, impact strength, and surface microhardness were evaluated. Independent sample t-tests were used to statistically analyze the data and compare the mean values of flexural strength, flexural modulus, impact strength, and surface microhardness (p-value ≤ 0.05). RESULTS The flexural strength of the modified groups with Ag-doped CNTs (132.4 MPa) was significantly greater than that of the unmodified (control) groups (63.2 MPa). Moreover, the flexural modulus of the modified groups with Ag-doped CNTs (3.067 GPa) was significantly greater than that of the control groups (1.47 GPa). Furthermore, the impact strength of the modified groups with Ag-doped CNTs (11.2 kJ/mm2) was significantly greater than that of the control groups (2.3 kJ/mm2). Furthermore, the microhardness of the modified groups with Ag-doped CNTs (29.7 VHN) was significantly greater than that of the control groups (16.4 VHN), (p-value = 0.0001). CONCLUSION The incorporation of 0.5% wt. silver doped CNTs fillers to the self-cured acrylic resin enhanced its flexural strength, flexural modulus, impact strength, and surface microhardness.
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Affiliation(s)
- Tamer M Hamdy
- Restorative and Dental Materials Department, Oral and Dental Research Institute, National Research Centre (NRC), Giza, Dokki, 12622, Egypt.
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Saini RS, Gurumurthy V, Quadri SA, Bavabeedu SS, Abdelaziz KM, Okshah A, Alshadidi AAF, Yessayan L, Mosaddad SA, Heboyan A. The flexural strength of 3D-printed provisional restorations fabricated with different resins: a systematic review and meta-analysis. BMC Oral Health 2024; 24:66. [PMID: 38200473 PMCID: PMC10782672 DOI: 10.1186/s12903-023-03826-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 12/25/2023] [Indexed: 01/12/2024] Open
Abstract
BACKGROUND Three-dimensional (3D) printing technology has revolutionized dentistry, particularly in fabricating provisional restorations. This systematic review and meta-analysis aimed to thoroughly evaluate the flexural strength of provisional restorations produced using 3D printing while considering the impact of different resin materials. METHODS A systematic search was conducted across major databases (ScienceDirect, PubMed, Web of Sciences, Google Scholar, and Scopus) to identify relevant studies published to date. The inclusion criteria included studies evaluating the flexural strength of 3D-printed provisional restorations using different resins. Data extraction and quality assessment were performed using the CONSORT scale, and a meta-analysis was conducted using RevMan 5.4 to pool results. RESULTS Of the 1914 initially identified research articles, only 13, published between January 2016 and November 2023, were included after screening. Notably, Digital Light Processing (DLP) has emerged as the predominant 3D printing technique, while stereolithography (SLA), Fused Deposition Modeling (FDM), and mono-liquid crystal displays (LCD) have also been recognized. Various printed resins have been utilized in different techniques, including acrylic, composite resins, and methacrylate oligomer-based materials. Regarding flexural strength, polymerization played a pivotal role for resins used in 3D or conventional/milled resins, revealing significant variations in the study. For instance, SLA-3D and DLP Acrylate photopolymers displayed distinct strengths, along with DLP bisacrylic, milled PMMA, and conventional PMMA. The subsequent meta-analysis indicated a significant difference in flexure strength, with a pooled Mean Difference (MD) of - 1.25 (95% CI - 16.98 - 14.47; P < 0.00001) and a high I2 value of 99%, highlighting substantial heterogeneity among the studies. CONCLUSIONS This study provides a comprehensive overview of the flexural strength of 3D-printed provisional restorations fabricated using different resins. However, further research is recommended to explore additional factors influencing flexural strength and refine the recommendations for enhancing the performance of 3D-printed provisional restorations in clinical applications.
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Affiliation(s)
- Ravinder S Saini
- Department of Dental Technology, COAMS, King Khalid University, Abha, Saudi Arabia
| | | | | | - Shashit Shetty Bavabeedu
- Department of Restorative Dental Sciences, College of Dentistry, King Khalid University, Abha, Saudi Arabia
| | - Khalid M Abdelaziz
- Department of Restorative Dental Sciences, College of Dentistry, King Khalid University, Abha, Saudi Arabia
| | - Abdulmajeed Okshah
- Department of Dental Technology, COAMS, King Khalid University, Abha, Saudi Arabia
| | | | - Lazar Yessayan
- Department of Therapeutic Stomatology, Faculty of Stomatology, Yerevan State Medical University after Mkhitar Heratsi, Yerevan, Armenia
| | - Seyed Ali Mosaddad
- Student Research Committee, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran.
| | - Artak Heboyan
- Department of Prosthodontics, Faculty of Stomatology, Yerevan State Medical University after Mkhitar Heratsi, Yerevan, Armenia.
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Hajjaj MS, Alamoudi RAA, Babeer WA, Rizg WY, Basalah AA, Alzahrani SJ, Yeslam HE. Flexural strength, flexural modulus and microhardness of milled vs. fused deposition modeling printed Zirconia; effect of conventional vs. speed sintering. BMC Oral Health 2024; 24:38. [PMID: 38185744 PMCID: PMC10771678 DOI: 10.1186/s12903-023-03829-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 12/26/2023] [Indexed: 01/09/2024] Open
Abstract
BACKGROUND Various methods can be used for creating zirconia dental restorations, including 3-dimensional (3D) printing and computer-aided design/ computer-aided manufacturing (CAD/CAM) milling. The fused deposition modeling (FDM) printing method for zirconia presents numerous advantages, albeit research on the mechanical properties of these materials and resultant restorations remains scarce. Such developments are undeniably intriguing and warrant further investigation. The objective of the present study was to evaluate the impact of the sintering firing cycle (Conventional vs. Speed sintering) on the flexural strength, flexural modulus, and Vickers Microhardness of milled vs. FDM printed zirconia. METHODS A total of 60 bars (2 × 5 × 27 mm) were fabricated for flexural strength testing, along with 40 discs (12 × 1.5 mm) for Vickers microhardness testing. Half of the specimens underwent conventional sintering, while the other half underwent a speed sintering cycle. The flexural strength and modulus were determined by a three-point bending test in a universal testing machine. The microhardness of the specimens was evaluated using a Vickers microhardness tester. Statistical analysis was performed using a two-way ANOVA test with a post-hoc Tukey test (p < 0.05). RESULTS CAD/CAM milled zirconia had significantly higher flexural strength and modulus than FDM-printed zirconia. The sintering process did not significantly affect the flexural strength or modulus of milled or FDM-printed zirconia. The milled speed sintering group had significantly higher values in the Vickers microhardness test compared to the other groups. CONCLUSIONS The mechanical properties of FDM-printed zirconia specimens were not found to be comparable to those of milled zirconia. Speed sintering cycle may produce milled zirconia restorations with similar flexural strength and modulus to conventional sintering, and even higher Vickers Microhardness values.
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Affiliation(s)
- Maher S Hajjaj
- Department of Restorative Dentistry, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia.
- Advanced Technology Dental Research Laboratory, King Abdulaziz University, P.O. Box 80209, Jeddah, 21589, Saudi Arabia.
| | - Rana A A Alamoudi
- Prosthodontic Master Student, Department of Oral and Maxillofacial Rehabilitation, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Walaa A Babeer
- Department of Oral and Maxillofacial Rehabilitation, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Waleed Y Rizg
- Department of Pharmaceutics, Faculty of Pharmacy, King Abdulaziz University, Jeddah, 21589, Saudi Arabia
- Center of Innovation in Personalized Medicine (CIPM), 3D Bioprinting Unit, King Abdulaziz University, Jeddah, 21589, Saudi Arabia
| | - Ahmad A Basalah
- Mechanical Engineering Department, College of Engineering and Architecture, Umm Al Qura University, Makkah, Saudi Arabia
| | - Saeed J Alzahrani
- Department of Restorative Dentistry, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Hanin E Yeslam
- Department of Restorative Dentistry, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia
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Sudharson NA, Gandhi N, Talwar H, Kurian N, Joseph M. A comparative analysis of mechanical and optical behavioral patterns of translucent zirconia ceramics. J Indian Prosthodont Soc 2024; 24:88-94. [PMID: 38263563 PMCID: PMC10896311 DOI: 10.4103/jips.jips_341_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 11/28/2023] [Accepted: 12/23/2023] [Indexed: 01/25/2024] Open
Abstract
AIM This research aimed to assess and compare the translucency and mechanical properties of partially stabilized zirconia in contrast to lithium disilicate, particularly within the context of translucent zirconia. SETTINGS AND DESIGN The experimental design entails examining fifty samples, with ten drawn from each of the five distinct categories of ceramic materials, as part of this in vitro study. Translucency is measured using the Konica Minolta CM-3600D spectrophotometer, assessing Delta E through Lab values against white and black backgrounds. Flexural strength is analyzed via a 3-point bend test on a universal testing machine, with a controlled crosshead speed set at 1 mm/min. MATERIALS AND METHODS The study included the five categories of ceramic materials, each consisting of ten samples: High-strength zirconia (Katana HT), translucent zirconia (e.max Zircad MT and Cercon ht ML), and lithium disilicate (Press MT and LT). The Konica Minolta CM-3600D spectrophotometer is utilized to measure the translucency parameter. This involves determining the color difference (Delta E) by comparing the L*a*b values against both white and black backgrounds. The flexural strength (FS) of zirconia and lithium disilicate materials was analyzed through a 3-point bend test, aiming to compare their respective strengths. The testing procedure was carried out on a universal testing machine with a controlled crosshead speed set at 1 mm/min. The FS was calculated using the formula σ = FL/πR3 for circular disks, where σ represents the FS, F is the fracture load, L is the span length in millimeters, and R is the radius of the disk. STATISTICAL ANALYSIS USED The Student's t-test was employed for statistical analysis. RESULTS The mean translucency parameter for e.max Press MT (6.33 ± 1.05) was significantly greater than all the specimens investigated. The Cercon ht ML exhibited a slightly higher translucency (2.18 ± 0.52) compared to e.max Zircad MT (1.49 ± 0.69), with a statistically significant difference (P = 0.022). Conversely, the FS of e.max Zircad MT (26.97 ± 2.06) was significantly greater (P < 0.001) than that of Cercon ht ML (23.25 ± 2.36). Notably, the Katana HT material demonstrated the highest load strength (32.92 ± 3.10), a statistically significant difference compared to its counterparts (P < 0.001). CONCLUSIONS Among the materials tested, lithium disilicate ceramics exhibited the highest translucency, with its MT variant demonstrating the lowest strength. Katana HT displayed significantly greater biaxial FS compared to translucent zirconia, surpassing even lithium disilicate. Translucent zirconia proved to be notably more translucent than high-strength zirconia. Within the category of translucent zirconia, e.max Zircad MT exhibited substantially higher FS than Cercon.
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Affiliation(s)
| | - Nitasha Gandhi
- Department of Prosthodontics, Christian Dental College, Ludhiana, Punjab, India
| | - Harit Talwar
- Department of Prosthodontics, Christian Dental College, Ludhiana, Punjab, India
| | - Nirmal Kurian
- Department of Prosthodontics, Christian Dental College, Ludhiana, Punjab, India
| | - Meril Joseph
- Department of Prosthodontics, Christian Dental College, Ludhiana, Punjab, India
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Chopra D, Guo T, Gulati K, Ivanovski S. Load, unload and repeat: Understanding the mechanical characteristics of zirconia in dentistry. Dent Mater 2024; 40:e1-e17. [PMID: 37891132 DOI: 10.1016/j.dental.2023.10.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 09/11/2023] [Accepted: 10/05/2023] [Indexed: 10/29/2023]
Abstract
OBJECTIVES Zirconia-based dental restorations and implants are gaining attention due to their bioactivity, corrosion resistance and mechanical stability. Further, surface modification of zirconia implants has been performed at the macro-, micro- and nanoscale to augment bioactivity. While zirconia's physical and chemical characteristics have been documented, its relation to mechanical performance still needs to be explored. This extensive review aims to address this knowledge gap. METHODS This review critically compares and contrasts the findings from articles published in the domain of 'mechanical stability of zirconia\ in dentistry' based on a literature survey (Web of Science, Medline/PubMed and Scopus databases) and a review of the relevant publications in international peer-reviewed journals. Reviewing the published data, the mechanical properties of zirconia, such as fracture resistance, stress/tension, flexural strength, fatigue, and wear are detailed and discussed to understand the biomechanical compatibility of zirconia with the mechanical performance of modified zirconia in dentistry also explored. RESULTS A comprehensive insight into dental zirconia's critical fundamental mechanical characteristics and performance is presented. Further, research challenges and future directions in this domain are recommended. SIGNIFICANCE This review extends existing knowledge of zirconia's biomechanical performance and it they can be modulated to design the next generation of zirconia dental restorations and implants to withstand long-term constant loading.
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Affiliation(s)
- Divya Chopra
- The University of Queensland, School of Dentistry, Herston, QLD 4006, Australia; Centre for Orofacial Regeneration, Reconstruction and Rehabilitation (COR3), Herston, QLD 4006, Australia
| | - Tianqi Guo
- The University of Queensland, School of Dentistry, Herston, QLD 4006, Australia; Centre for Orofacial Regeneration, Reconstruction and Rehabilitation (COR3), Herston, QLD 4006, Australia
| | - Karan Gulati
- The University of Queensland, School of Dentistry, Herston, QLD 4006, Australia; Centre for Orofacial Regeneration, Reconstruction and Rehabilitation (COR3), Herston, QLD 4006, Australia.
| | - Sašo Ivanovski
- The University of Queensland, School of Dentistry, Herston, QLD 4006, Australia; Centre for Orofacial Regeneration, Reconstruction and Rehabilitation (COR3), Herston, QLD 4006, Australia.
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Çoban Öksüzer M, Şanal Çıkman A. Evaluation of Fracture Strength after Repair of Cervical External Resorption Cavities with Different Materials. J Endod 2024; 50:85-95. [PMID: 37879603 DOI: 10.1016/j.joen.2023.10.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 10/07/2023] [Accepted: 10/16/2023] [Indexed: 10/27/2023]
Abstract
INTRODUCTION The aim was to evaluate the stress distributions on dentin and repair materials caused by static force applied to teeth, with cervical external root resorption (CER) after repair with different materials using finite element analysis. METHODS This study was performed with the 3-dimensional finite element analysis method. Access cavity, root canal cavity dimensions, and supporting tissues other than cementum were modeled in the maxillary central tooth. The CER cavity was created on the labial side of the tooth model. The coronal side of the resorption cavity was restored with composite, and the radicular side with different materials (MTA, Biodentine, BioAggregate, calcium-enriched cement [CEM], glass ionomer cement [GIC], and resin-modified glass ionomer cement [RMGIC]). A static force of 300 N was applied to the palatal surface of the crown at an angle of 135° to the long axis of the tooth. The stress distributions in dentin and repair materials were analyzed. RESULTS The highest stress in dentin was seen in the fFigmodel with unrepaired CER. In the models repaired with MTA, GIC, and RMGIC, von Mises stress values in dentin were greater than for repairs with Biodentine, BioAggregate, and CEM materials. The von Mises stress on the repair materials applied to the root were highest for the BioAggregate material. This was followed by CEM, Biodentine, MTA, RMGIC, and GIC materials, respectively. CONCLUSION The repair of CER in the tooth significantly decreased the stress values in dentin. Biodentine, BioAggregate, and CEM absorbed more force and caused less stress to be transmitted to dentin compared to MTA, GIC, and RMGIC.
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Affiliation(s)
- Merve Çoban Öksüzer
- Department of Endodontics, Faculty of Dentistry, Recep Tayyip Erdoğan University, Rize, Türkiye.
| | - Ahter Şanal Çıkman
- Department of Endodontics, Faculty of Dentistry, Recep Tayyip Erdoğan University, Rize, Türkiye
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Albakri IA, AlHorani Z, Hatamleh M, Al-Omari WM. Evaluation of Shade Reproducibility and Mechanical Properties of Preshaded and Manually Shaded Monolithic Zirconia. Oper Dent 2024; 49:110-116. [PMID: 38180471 DOI: 10.2341/23-016-l] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/01/2023] [Indexed: 01/06/2024]
Abstract
OBJECTIVES This study aimed to investigate the effect of manual coloring of blank monolithic zirconia blocks of four materials on their shade reproducibility, flexural strength, and surface roughness as compared with preshaded blocks of the same material. METHODS AND MATERIALS Eight disc-shaped specimens (diameter=12mm; height=2mm) and eight bar-shaped specimens (25×2×2 mm) were milled from the shaded and non-shaded blocks of the four zirconia systems: Ceramill, Kerox, White Peaks, and Dental Direkt. In total, 128 specimens were fabricated. The non-shaded specimens of each system were coloured according to A2 shade. The surface roughness (Ra) was measured using a contact profilometer. Color difference was calculated according to the CIEDE2000 formula. The bar-shaped specimens were loaded to fracture following three-point bend testing at 1 mm/minute crosshead speed. Data were analysed following one-way analysis of variance (ANOVA), and the Tukey post-hoc test (p=0.05). RESULTS Manual-coloring affected the surface roughness, color difference, and flexural strength of three materials in comparison to their preshaded blocks (p<0.05). White Peaks was not affected (p>0.05). Ra values ranged from 1.1-1.9; three materials were not affected (p>0.05). Kerox preshaded blocks were the smoothest (p<0.05) but became the roughest once colored (p<0.05). White Peaks and Dental Direkt materials had preshaded blocks matching the A2 guide-tab (p>0.05). DE was perceptible and unacceptable for the preshaded and manually shaded blocks of all materials tested (ΔE>1.8). While manual coloring reduced flexural strength of Ceramill and Dental Direkt (p<0.05), flexural strength was retained by Kerox and White Peaks (p>0.05). CONCLUSIONS White Peaks was not affected by the coloring technique. Coloring had negative effects on Ceramill flexural strength and color reproducibility.
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Affiliation(s)
- I A Albakri
- *Isra' Abdelkarim Moh'd Albakri, MPhiL, PhD, assistant professor, Department of Applied Dental Sciences, Faculty of Applied Medical Sciences, Jordan University of Science and Technology, Irbid-Jordan
| | - Z AlHorani
- Zaid AlHourani, PhD, associate professor, Department of Applied Dental Sciences, Faculty of Applied Medical Sciences, Jordan University of Science and Technology, Irbid-Jordan
| | - M Hatamleh
- Muhanad Hatamleh, PhD, professor, Department of Applied Dental Sciences, Faculty of Applied Medical Sciences, Jordan University of Science and Technology, Irbid-Jordan
| | - W M Al-Omari
- Wael M Al-Omari, PhD, professor, Department of Prosthodontics, Faculty of Dentistry, Jordan University of Science and Technology, Irbid-Jordan
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Lima KDC, Vivanco RG, Rodrigues PRB, Caetano ALP, Pires-de-Souza FDCP. Long-term effect of firing protocols on surface roughness and flexural strength of lithium disilicate glass-ceramic. Braz Dent J 2023; 34:79-86. [PMID: 38133476 PMCID: PMC10759956 DOI: 10.1590/0103-6440202305496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 08/29/2023] [Indexed: 12/23/2023] Open
Abstract
This study evaluated the effect of different firing protocols on the surface roughness and flexural strength of CAD/CAM lithium disilicate glass-ceramic (LD) after aging methods. Forty-two LD bars of 16 x 4 x 2 mm (IPS e-max CAD, Ivoclar) were randomly separated into two groups according to firing protocols: Single firing-Staining, glazing, and crystallization in a single step; Multiple firings-Crystallization+First staining+Firing+Second staining+Firing+Glazing+Firing. After protocols, initial surface roughness readings were taken (Surfcorder SE1700, Kosakalab). Samples were then randomly separated into three groups (n=7) according to the aging methods they were submitted: Thermomechanical cycling (TMC, ER System, Erios, 1,200,000 cycles, 0.3 MPa, 2 Hz and 5°C/37°C/55°C, 30 s swell time); Simulated toothbrushing (STB, Pepsodent, MAVTEC, 73,000 cycles), and Control (no aging). Final surface roughness readings were done, and samples were submitted to a three-point bending test (OM100, Odeme Dental Research) and fractographic analysis by scanning electron microscopy (EVO-MA10, ZEISS). Data were analyzed (2-way ANOVA, (α=.05). There was no difference (p>.05) in the flexural strength between the firing protocols, regardless of the aging method. STB decreased the flexural strength of samples submitted to multiple firings, different from control (p<.05). Without aging (Control), before TMC, and after STB, LD had lower surface roughness when submitted to multiple firings than to single firing (p<.05). The firing protocols did not affect the flexural strength or the surface roughness of the lithium disilicate glass-ceramic, even after aging. However, toothbrushing negatively affected the flexural strength and smoothed the surface of the ceramic submitted to multiple firings.
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Affiliation(s)
- Kaíssa da Cunha Lima
- Department of Dental Materials and Prosthesis Ribeirão Preto School of Dentistry - University of Sao Paulo. Av do Café s/n, 14040-904 Ribeirão Preto, SP, Brazil
| | - Rocio Geng Vivanco
- Department of Dental Materials and Prosthesis Ribeirão Preto School of Dentistry - University of Sao Paulo. Av do Café s/n, 14040-904 Ribeirão Preto, SP, Brazil
| | - Pedro Roberto Braz Rodrigues
- Department of Dental Materials and Prosthesis Ribeirão Preto School of Dentistry - University of Sao Paulo. Av do Café s/n, 14040-904 Ribeirão Preto, SP, Brazil
| | - Ana Lúcia Pereira Caetano
- Department of Dental Materials and Prosthesis Ribeirão Preto School of Dentistry - University of Sao Paulo. Av do Café s/n, 14040-904 Ribeirão Preto, SP, Brazil
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Bahrami R, Sodagar A, Pourhajibagher M, Mirhashemi AH. The effect of different concentration of emodin nanoparticles, as an antibacterial agent, on the flexural resistance of acrylic resin used in orthodontics: An in vitro study. Int Orthod 2023; 21:100811. [PMID: 37774500 DOI: 10.1016/j.ortho.2023.100811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 08/22/2023] [Accepted: 08/23/2023] [Indexed: 10/01/2023]
Abstract
OBJECTIVE The aim of this study was to investigate the impact of emodin nanoparticles (n-Emo) on the flexural strength of acrylic resin used in orthodontics. METHODS A total of 24 acrylic resin discs were prepared according to ISO:20795-1 and divided into four groups (n=6): 0% n-Emo, 0.5% n-Emo, 1% n-Emo, and 2% n-Emo. The flexural strength of each group was measured using the Universal Testing Machine. One-way analysis of variance (ANOVA) and Tukey tests were used to analyse the data. RESULTS The highest flexural strength values were observed in the groups containing 0% and 0.5% concentrations of n-Emo, while the lowest mean flexural strength was recorded in the group containing 2% concentration of n-Emo. There were significant difference in flexural strength values between the groups containing 0% with those containing 1% and 2% concentrations (P=0.045, P=0.011, respectively), as well as between those containing 0.5% and 2% concentrations of n-Emo (P=0.041). CONCLUSIONS The results of the study showed that the incorporation of n-Emo had a negative impact on the flexural strength of the acrylic resin utilized in orthodontics. Nonetheless, the mean flexural strength values of all groups fell within the normal range, implying that the addition of n-Emo did not jeopardize the mechanical properties of the acrylic resin. It is therefore conceivable that the use of n-Emo as an antimicrobial agent in acrylic resin could be a promising approach to reducing enamel demineralisation and dental caries, while preserving its mechanical properties. This study was approved by the ethics committee of the Tehran University of Medical Sciences (1401-2-398-54892).
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Affiliation(s)
- Rashin Bahrami
- Department of Orthodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran
| | - Ahmad Sodagar
- Department of Orthodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran
| | - Maryam Pourhajibagher
- Dental Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Amir Hossein Mirhashemi
- Department of Orthodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran.
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Kim SH, Oh NS, Pang NS, Jung BY. The effect of surface treatment and low-temperature degradation on flexural strength of additive manufactured zirconia. J Mech Behav Biomed Mater 2023; 148:106167. [PMID: 37837875 DOI: 10.1016/j.jmbbm.2023.106167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 10/04/2023] [Accepted: 10/06/2023] [Indexed: 10/16/2023]
Abstract
This study aimed to assess the effect of low-temperature degradation (LTD) and surface treatment on the flexural strength of additive-manufactured (AM) zirconia by comparison to subtractive-manufactured (SM) zirconia. Disc-shaped zirconia specimens were fabricated using AM and SM technology, and each group was assigned to 3 subgroups according to the type of surface treatment: control, sandblasting (SB), and 9% hydrofluoric acid etching (HF). The groups were then further divided into 2 subgroups: unaged and aged. Biaxial flexural strength, crystal phase, surface topography, and surface roughness were measured to evaluate the mechanical properties. Statistical analyses were performed with 3-way ANOVA, followed by the comparison of means with Bonferroni post hoc analyses. The means and standard deviations of the biaxial flexural strength and Weibull parameters were calculated with descriptive statistics. All SM groups showed significantly greater flexural strength than the AM groups (p < .05), and LTD did not affect flexural strength except for the SMHF group (p < .05). After LTD, monoclinic phases (m-phase) were found in all groups, and SEM images showed grain pullout due to zirconia volume expansion in both control groups. Sandblasting significantly affected flexural strength (p < .05), whereas the HF group did not affect flexural strength except in the SMHF group after LTD (p < .05). No significant difference was observed in the surface roughness of AM compared to SM groups conditioned with the same surface treatment regardless of LTD. AM zirconia has comparable mechanical properties to SM zirconia, regardless of low-temperature degradation and surface treatment, which indicates the potential of the AM technique for clinical applications.
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Affiliation(s)
- So-Hyun Kim
- Department of Dentistry, Inha University School of Medicine, Inha University Hospital, Incheon, South Korea.
| | - Nam-Sik Oh
- Department of Dentistry, Inha University School of Medicine, Inha University Hospital, Incheon, South Korea.
| | - Nan-Sim Pang
- Department of Advanced General Dentistry, Yonsei University, College of Dentistry, Seoul, South Korea.
| | - Bock-Young Jung
- Department of Advanced General Dentistry, Yonsei University, College of Dentistry, Seoul, South Korea.
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Benli M, Al-Haj Husain N, Ozcan M. Mechanical and chemical characterization of contemporary occlusal splint materials fabricated with different methods: a systematic review. Clin Oral Investig 2023; 27:7115-7141. [PMID: 37910242 DOI: 10.1007/s00784-023-05360-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Accepted: 10/22/2023] [Indexed: 11/03/2023]
Abstract
OBJECTIVE To systematically review studies on various occlusal splint materials and describe their mechanical and chemical properties. METHODS MEDLINE (PubMed), Scopus, and Web of Science searches were conducted for in vitro studies focusing on occlusal splint materials. Two reviewers performed an assessment of the identified studies and data abstraction independently, and this was complimented by an additional hand search. The articles were limited to those in the English language that were published between January 1st, 2012, and December 1st, 2022. RESULTS The initial search yielded 405 search results of which 274 were selected for full-text review following abstract evaluation. 250 articles that did not meet the inclusion criteria were excluded, and the remaining 25 articles (with 1 article identified from the reference lists of included articles) providing mechanical and chemical values were used in this review. Poly methyl methacrylate (PMMA) -based occlusal splint materials showed the highest values in terms of hardness, wear resistance, flexural strength, flexural modulus, e-modulus, and fracture toughness. The material group with the highest water sorption and water solubility was 3D printed (PR) splint materials. In addition, the lowest degree of double bond conversion was also observed in this group of materials. CONCLUSIONS The outcome of this review suggests that mechanically and chemically acceptable properties can be attained with PMMA-based occlusal splint materials using both conventional and digital production methods. PR splint materials should not be considered as the primary choice for long-term treatments due to their low mechanical and chemical properties. CLINICAL RELEVANCE This review provides clinical recommendations for selecting the appropriate material and fabrication method for occlusal splints while taking the patients' needs and the materials´ mechanical and chemical properties into account.
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Affiliation(s)
- Merve Benli
- James B. Edwards College of Dental Medicine, Department of Oral Rehabilitation, Division of Removable Prosthodontics, MUSC, Charleston, USA.
- Department of Prosthodontics, Faculty of Dentistry, Istanbul University, Istanbul, Turkey.
| | - Nadin Al-Haj Husain
- Division of Dental Biomaterials, Clinic for Reconstructive Dentistry, Center of Dental Medicine, University of Zurich, 8032, Zurich, Switzerland
- Department of Reconstructive Dentistry and Gerodontology, School of Dental Medicine, University of Bern, 3010, Bern, Switzerland
- Clinic of Masticatory Disorders, Center of Dental Medicine, University of Zurich, 8032, Zurich, Switzerland
| | - Mutlu Ozcan
- Division of Dental Biomaterials, Center for Dental Medicine, Clinic for Reconstructive Dentistry, University of Zurich, Plattenstrasse 11, 8032, Zurich, Switzerland
- Clinic for Chewing Function Disturbances, Center for Dental Medicine, Clinic for Reconstructive Dentistry, University of Zurich, Plattenstrasse 11, 8032, Zurich, Switzerland
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La Rosa GRM, Leotta ML, Canova FS, Romeo VR, Cervino G, Generali L, Pedullà E. Cyclic fatigue resistance of different nickel-titanium instruments in single and double curvature at room and body temperatures: A laboratory study. AUST ENDOD J 2023; 49:592-598. [PMID: 37592880 DOI: 10.1111/aej.12789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 08/07/2023] [Indexed: 08/19/2023]
Abstract
The aim of this study was to compare the cyclic fatigue resistance of nickel-titanium instruments inside single and double-curved canals at different temperatures. 160 HyFlex EDM #20.05 (HEDM), VDW.ROTATE #20.05 and #25.06, Mtwo #25.06 were randomised (n = 10) for the dynamic cyclic fatigue tests according to the curvature (i.e. single and double) at 20° ± 1°C and 35° ± 1°C. The number of cycles to fracture (NCF) was analysed by two-way ANOVA with p < 0.05. Fatigue resistance of all instruments significantly decreased at body temperature in single and double curvatures, except for HEDM in double curvature. The NCF was significantly lower in double curvature than single at both temperatures for all files, except for VDW.ROTATE #20.05 at 35° ± 1°C. Within the study limitations, temperature significantly impaired cyclic fatigue resistance of all files except HEDM #20.05 in double curvature. Similarly, double curvature had a detrimental effect on cyclic fatigue resistance of all files except for VDW.ROTATE #20.05 at body temperature.
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Affiliation(s)
- Giusy Rita Maria La Rosa
- Department of General Surgery and Medical-Surgical Specialties, University of Catania, Catania, Italy
| | - Maria Laura Leotta
- Department of General Surgery and Medical-Surgical Specialties, University of Catania, Catania, Italy
| | - Francesco Saverio Canova
- Department of General Surgery and Medical-Surgical Specialties, University of Catania, Catania, Italy
| | - Virginia Rosy Romeo
- Department of General Surgery and Medical-Surgical Specialties, University of Catania, Catania, Italy
| | - Gabriele Cervino
- Department of Biomedical and Dental Sciences and Morphological and Functional Imaging, Messina University, Messina, Italy
| | - Luigi Generali
- Department of Surgery, Medicine, Dentistry and Morphological Sciences with Transplant Surgery, Oncology and Regenerative Medicine Relevance (CHIMOMO), University of Modena and Reggio Emilia, Modena, Italy
| | - Eugenio Pedullà
- Department of General Surgery and Medical-Surgical Specialties, University of Catania, Catania, Italy
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Attia MA, Radwan M, Blunt L, Bills P, Tawfik A, Arafa AM. Effect of different sintering protocols on the fracture strength of 3-unit monolithic gradient zirconia fixed partial dentures: An in vitro study. J Prosthet Dent 2023; 130:908.e1-908.e8. [PMID: 37802734 DOI: 10.1016/j.prosdent.2023.09.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 09/12/2023] [Accepted: 09/13/2023] [Indexed: 10/08/2023]
Abstract
STATEMENT OF PROBLEM Strength-gradient zirconia combining 3 zirconia formulations with different flexural strengths has been reported to have outstanding mechanical properties. However, data concerning the effect of different sintering protocols on the fracture strength of 3-unit monolithic gradient zirconia fixed partial dentures (FPDs) are sparse. PURPOSE The purpose of this in vitro study was to test the effect of different sintering protocols on the fracture strength of 3-unit monolithic gradient zirconia FPDs. MATERIAL AND METHODS Two custom-made stainless-steel master dies were designed to replicate a mandibular right second premolar and second molar prepared to receive a 3-unit monolithic zirconia FPD. Thirty monolithic zirconia FPDs were milled from gradient zirconia blanks and allocated to 3 groups (n=10) according to the sintering protocols: high-speed sintering, speed sintering, and conventional sintering. The FPDs were cemented onto the corresponding dies with traditional glass ionomer cement. All FPDs were cyclic loaded (600 000 cycles/49 N/1.7 Hz) in a mastication simulator. Fracture load measurements for each FPD were determined by using a universal testing machine. Scanning electron microscopy (SEM) at ×80 magnification was used to examine a fractured FPD from each group. A representative specimen from each group was examined with SEM at ×30 000 magnification to determine the grain size. One-way ANOVA, pair-wise Tukey honestly significant difference (HSD), and Pearson correlation tests were used for statistical analysis of the data (α=.05). RESULTS The high-speed sintered FPDs recorded the highest statistically significant fracture load mean ±standard deviation value (2526 ±300 N), followed by the speed sintered FPDs (2136 ±127 N), while the lowest statistically significant fracture load mean value was recorded with the conventionally sintered FPDs (1361 ±181 N) (P<.001). In addition, the mean ±standard deviation grain size values were 488 ±272 nm for the high-speed sintered specimen, 578 ±409 nm for the speed sintered specimen, and 832 ±551 nm for the conventionally sintered specimen (P<.001). A significant negative correlation was found between fracture strength and grain size among the 3 groups. CONCLUSIONS The fracture strength of 3-unit monolithic gradient zirconia FPDs sintered by using a high-speed protocol was significantly higher than that of speed and conventionally sintered FPDs (P<.001). The high-speed sintering protocol reduced the mean grain size of gradient zirconia FPDs compared with that of both speed and conventional sintering protocols.
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Affiliation(s)
- Mazen A Attia
- Associate Professor, Department of Fixed Prosthodontics, Faculty of Dentistry, Beni-Suef University, Beni-Suef, Egypt.
| | - Mohamed Radwan
- Lecturer, Department of Fixed Prosthodontics, Faculty of Dentistry, Beni-Suef University, Beni-Suef, Egypt
| | - Liam Blunt
- Professor, Engineering and Physical Sciences Research Council (EPSRC) Future Advanced Metrology Hub, University of Huddersfield, Huddersfield, England, United Kingdom
| | - Paul Bills
- Professor, Engineering and Physical Sciences Research Council (EPSRC) Future Advanced Metrology Hub, University of Huddersfield, Huddersfield, England, United Kingdom
| | - Ahmed Tawfik
- PhD Researcher, Engineering and Physical Sciences Research Council (EPSRC) Future Advanced Metrology Hub, University of Huddersfield, Huddersfield, England, United Kingdom
| | - Ahmed M Arafa
- Lecturer, Department of Fixed Prosthodontics, Faculty of Dentistry, Beni-Suef University, Beni-Suef, Egypt
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Al Fodeh RS, Al-Johi OS, Alibrahim AN, Al-Dwairi ZN, Al-Haj Husain N, Özcan M. Fracture strength of endocrown maxillary restorations using different preparation designs and materials. J Mech Behav Biomed Mater 2023; 148:106184. [PMID: 37839334 DOI: 10.1016/j.jmbbm.2023.106184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 10/07/2023] [Accepted: 10/10/2023] [Indexed: 10/17/2023]
Abstract
PURPOSE This study investigated the impact of preparation design and material types on fracture strength in maxillary premolars endocrowns after thermodynamic aging. MATERIALS AND METHODS Eighty two-rooted maxillary premolar crowns underwent endodontic treatment (N = 80, n = 10). The teeth were categorized into ten groups (4-mm deep with no intracanal extension lithium disilicate glass ceramic & multilayer zirconia endocrowns (LE0 & ZE0); 4-mm deep with 4-mm intracanal extension in one canal (LE1 & ZE1); 4-mm deep with 2-mm intracanal extensions in both canals (LE2 & ZE2); flat overlays with no endocore (LO & ZO); glass fiber reinforced post & core and crown (LC & ZC)). After cementation, all specimens were subjected to 1500 thermocycles and 1,200,000 chewing cycles with an axial occlusal load of 49 N. A static loading test was performed at a non-axial 45° loading using a universal testing machine and failure modes (Type I: restoration debonding; Type II: restoration fracture; Type III: restoration/tooth complex fracture above bone level; Type IV: restoration/tooth complex fracture below bone level) were evaluated using a stereoscope. Data were ananalzed using 2-way ANOVA and Tukey's tests (alpha = 0.05). RESULTS The endocrowns manufactured from multilayered zirconia and pressed lithium disilicate glass ceramic exhibited a fracture load ranging between 1334 ± 332 N and 756 ± 150 N, with ZC presenting the highest and LE2 the lowest values. The differences were not statistically significant (p > 0.05). CONCLUSION All endocrowns tested in this study performed similar considering the different designs and materials tested. The distribution of fracture modes did not differ significantly depending on the design of the restoration and the type of material used.
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Affiliation(s)
- Rami S Al Fodeh
- Department of Prosthodontics, Faculty of Dentistry, Jordan University of Science and Technology, Irbid, Jordan
| | - Omer S Al-Johi
- Department of Prosthodontics, Faculty of Dentistry, Jordan University of Science and Technology, Irbid, Jordan
| | - Anas N Alibrahim
- Department of Prosthodontics, Faculty of Dentistry, Jordan University of Science and Technology, Irbid, Jordan
| | - Ziad N Al-Dwairi
- Department of Prosthodontics, Faculty of Dentistry, Jordan University of Science and Technology, Irbid, Jordan
| | - Nadin Al-Haj Husain
- Division of Dental Biomaterials, Clinic for Reconstructive Dentistry, Center of Dental Medicine, University of Zurich, Zurich, Switzerland; Clinic of Masticatory Disorders and Dental Biomaterials, Center of Dental Medicine, University of Zurich, Zurich, Switzerland; Department of Reconstructive Dentistry and Gerodontology, School of Dental Medicine, University of Bern, Bern, Switzerland
| | - Mutlu Özcan
- Division of Dental Biomaterials, Clinic for Reconstructive Dentistry, Center of Dental Medicine, University of Zurich, Zurich, Switzerland; Clinic of Masticatory Disorders and Dental Biomaterials, Center of Dental Medicine, University of Zurich, Zurich, Switzerland.
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Pereira RM, Moreira Bastos Campos T, Augusto Bonfante E, Patrocínio Thim G. A comparative study of mechanical properties of yttria stabilized zirconia monolithic and bilayer configuration for dental application. J Mech Behav Biomed Mater 2023; 148:106160. [PMID: 37832171 DOI: 10.1016/j.jmbbm.2023.106160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Revised: 09/28/2023] [Accepted: 09/30/2023] [Indexed: 10/15/2023]
Abstract
Zirconia multilayer presents promising prospects, but there is scarce information about its microstructural and mechanical characterization. Therefore, this study sought to produce them in-house and to perform their characterization by comprising four groups of specimens to assess the biaxial flexural strength, microhardness, fracture toughness, phase characterization and quantification, fractography, and microstructural features. Weibull analysis was performed to determine the Weibull modulus and characteristic strength. The results showed that bilayers 3YSZ and 5YSZ presented intermediate mechanical properties when compared to 3YSZ and 5YSZ monolithic controls (680 MPa, 464 MPa, 885 MPa, 594 MPa, respectively). Fractographic analysis revealed that the failure origin was not at the interface in the bilayer groups, but residual stress was present between the layers. Hardness and fracture toughness were not affected by the interface.
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Affiliation(s)
- Raíssa Monteiro Pereira
- Laboratory of Plasma and Process, Technological Institute of Aeronautics, Praça Marechal Eduardo Gomes, 50, Vila das Acácias, São José dos Campos, SP, 12228-900, Brazil.
| | - Tiago Moreira Bastos Campos
- Laboratory of Plasma and Process, Technological Institute of Aeronautics, Praça Marechal Eduardo Gomes, 50, Vila das Acácias, São José dos Campos, SP, 12228-900, Brazil
| | - Estevam Augusto Bonfante
- Department of Prosthodontics and Periodontology, Bauru School of Dentistry - University of São Paulo, Bauru, SP, Brazil
| | - Gilmar Patrocínio Thim
- Laboratory of Plasma and Process, Technological Institute of Aeronautics, Praça Marechal Eduardo Gomes, 50, Vila das Acácias, São José dos Campos, SP, 12228-900, Brazil
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Diken Türksayar AA, Demirel M, Donmez MB. Optical properties, biaxial flexural strength, and reliability of new-generation lithium disilicate glass-ceramics after thermal cycling. J Prosthodont 2023; 32:815-820. [PMID: 36585789 DOI: 10.1111/jopr.13632] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 11/24/2022] [Accepted: 12/16/2022] [Indexed: 01/01/2023] Open
Abstract
PURPOSE To investigate the color stability, translucency, biaxial flexural strength (BFS), and reliability of nano-lithium disilicate and fully crystallized lithium disilicate after thermal cycling and to compare with those of a commonly used lithium disilicate. MATERIALS AND METHODS Three lithium disilicate glass-ceramics were used to prepare disk-shaped specimens (ø:12 mm, thickness: 1.2 mm) from A2 shaded HT blocks (Amber Mill, AM; Initial LiSi Block, IN; IPS e.max CAD, EX). AM and EX specimens were crystallized, and all specimens were polished with a polishing paste (Diamond Polish Mint). A spectrophotometer (CM-26d) was used to measure color coordinates before and after thermal cycling. BFS test was performed after thermal cycling. Color differences (ΔE00 ) and relative translucency parameter (RTP) values were calculated. One-way analysis of variance (ANOVA) (ΔE00 and BFS), two-way ANOVA followed by Tukey's HSD tests (RTP), and chi-square tests (Weibull modulus and characteristic strength) were used for the statistical analyses (α = 0.05). RESULTS No significant differences were observed among the ΔE00 values of tested materials (df = 2, F = 2.933, p = 0.070). RTP values were only affected by material type (p < 0.001) as AM had the highest RTP (p < 0.001), whereas IN and EX had similar values (p ≥ 0.165). BFS values varied among tested materials (df = 2, F = 21.341, p < 0.001). AM and EX had similar BFS values (p = 0.067) that were higher than that of IN (p ≤ 0.001). Weibull moduli of the materials were similar (p = 0.305), whereas EX had the highest and IN had the lowest characteristic strength values (p < 0.001) CONCLUSIONS: Although nano-lithium disilicate had the highest translucency, all materials had imperceptible color and translucency changes after thermal cycling when reported threshold values were considered. Newly introduced lithium disilicate glass-ceramics had adequate flexural strength as compared to the precursor material.
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Affiliation(s)
- Almira Ada Diken Türksayar
- Department of Prosthodontics, Faculty of Dentistry, Biruni University, İstanbul, Turkey
- ADMiRE Research Center-Additive Manufacturing, Intelligent Robotics, Sensors and Engineering, School of Engineering and IT, Carinthia University of Applied Sciences, Villach, Austria
| | - Münir Demirel
- Oral and Dental Health, Vocational School, Biruni University, İstanbul, Turkey
| | - Mustafa Borga Donmez
- Department of Prosthodontics, Faculty of Dentistry, Istinye University, İstanbul, Turkey
- Department of Reconstructive Dentistry and Gerodontology, School of Dental Medicine, University of Bern, Bern, Switzerland
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de Almeida ENM, Victorino KR, Besegato JF, Costa JLDSG, Leandrin TP, Vitória MS, de Andrade MF, Kuga MC. Fracture strength and hybrid layer formation of endodontically-treated teeth after dental bleaching photoactivated with violet LED. Photodiagnosis Photodyn Ther 2023; 44:103813. [PMID: 37748699 DOI: 10.1016/j.pdpdt.2023.103813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 09/01/2023] [Accepted: 09/22/2023] [Indexed: 09/27/2023]
Abstract
OBJECTIVE To evaluate in vitro the effect of dental bleaching using high concentration hydrogen peroxide (HP) photoactivated with violet LED on fracture strength and hybrid layer formation. METHODS forty endodontically-treated bovine teeth were randomized into four groups (n = 10): C - Control, HP - 35% hydrogen peroxide, HP-BL - 35% hydrogen peroxide photoactivated with blue LED, HP-VL - 35% hydrogen peroxide photoactivated with violet LED. Three bleaching sessions with an interval of 7 days between them were performed. After 10 days of the last bleaching session, the dental crowns were restored and submitted to the fracture strength test. Five specimens from each group were used to evaluate the hybrid layer formation by scanning electron microscope (SEM) images. One-way ANOVA and Kruskal-Wallis test were used for parametric and non-parametric data, respectively. Significance level of 5% was adopted to all the tests. RESULTS No differences on fracture strength among the groups were observed (p > 0.05). HP and HP-BL showed alterations on hybrid layer formation compared to C group (p < 0.05), but not for HP-VL (p > 0.05). No differences on hybrid layer formation were observed among HP, HP-VL and HP-BL groups (p > 0.05). CONCLUSION Dental bleaching, photoactivated or not, did not affect the fracture strength of endodontically-treated teeth. Regardless of the protocol used, hydrogen peroxide altered the hybrid layer formation at some level when the restoration was placed after 10 days of the last bleaching session.
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Affiliation(s)
- Eran Nair Mesquita de Almeida
- Department of Restorative Dentistry, School of Dentistry, São Paulo State University - UNESP, Araraquara, SP, Brazil
| | - Keli Regina Victorino
- Department of Restorative Dentistry, School of Dentistry, São Paulo State University - UNESP, Araraquara, SP, Brazil
| | - João Felipe Besegato
- School of Dentistry, Federal University of Mato Grosso do Sul - UFMS, Campo Grande, MS, Brazil
| | - Joatan Lucas de Sousa Gomes Costa
- Department of Restorative Dentistry, School of Dentistry, Araraquara School of Dentistry, Federal University of Minas Gerais, 1680 Humaitá Street - 3rd floor, Araraquara - SP, Belo Horizonte, MG 14801-385, Brazil.
| | - Thais Piragine Leandrin
- Department of Restorative Dentistry, School of Dentistry, São Paulo State University - UNESP, Araraquara, SP, Brazil
| | - Matheus Sousa Vitória
- Department of Restorative Dentistry, School of Dentistry, São Paulo State University - UNESP, Araraquara, SP, Brazil
| | - Marcelo Ferrarezi de Andrade
- Department of Restorative Dentistry, School of Dentistry, São Paulo State University - UNESP, Araraquara, SP, Brazil
| | - Milton Carlos Kuga
- Department of Restorative Dentistry, School of Dentistry, São Paulo State University - UNESP, Araraquara, SP, Brazil
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Eldafrawy M, Karevan Y, Nguyen JF, Mainjot A. Interblock and intrablock homogeneity of CAD-CAM composites mechanical properties. Dent Mater J 2023; 42:780-790. [PMID: 37853645 DOI: 10.4012/dmj.2023-090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2023]
Abstract
The purpose of this study was to characterize the homogeneity of the mechanical properties of commercial CAD-CAM composites between different blocks of the same material (interblock homogeneity) and within each block between the internal and external parts (intrablock homogeneity). Tetric CAD (TET); Katana Avencia (KAT); Cerasmart 270 (CER); Grandio (GRN) and Vita Enamic (ENA) were tested for flexural strength (σf), flexural modulus (Ef), flexural load energy (Ur) and hardness (HV). Results showed significant differences in interblock homogeneity of σf, Ef and Ur for TET, KAT, CER and ENA. In addition, significant differences in interblock homogeneity of HV for TET, CER and GRN were found. Moreover, significant differences in intrablock homogeneity of σf, Ef and Ur were found for KAT, CER, GRN and ENA, as well as for HV of all the tested materials except CER. Weibull modulus was highest for GRN, followed by ENA, KAT, TET then CER.
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Affiliation(s)
- Maher Eldafrawy
- Dental Biomaterials Research Unit (d-BRU), Institute of Dentistry, University of Liège (ULiège)
- Department of Fixed Prosthodontics, Institute of Dentistry, University of Liège Hospital (CHU)
| | - Yousef Karevan
- Dental Biomaterials Research Unit (d-BRU), Institute of Dentistry, University of Liège (ULiège)
| | - Jean-François Nguyen
- Innovative Dental Materials and Interfaces Research Unit (UR 4462), Université Paris Cité
| | - Amélie Mainjot
- Dental Biomaterials Research Unit (d-BRU), Institute of Dentistry, University of Liège (ULiège)
- Department of Fixed Prosthodontics, Institute of Dentistry, University of Liège Hospital (CHU)
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Thanyasiri S, Naruphontjirakul P, Padunglappisit C, Mirchandani B, Young AM, Panpisut P. Assessment of physical/mechanical properties and cytotoxicity of dual-cured resin cements containing Sr-bioactive glass nanoparticles and calcium phosphate. Dent Mater J 2023; 42:806-817. [PMID: 37880134 DOI: 10.4012/dmj.2023-127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2023]
Abstract
The aim was to develop dual-cured resin cements containing Sr-bioactive glass nanoparticles (Sr-BGNPs; 5 or 10 wt%) and monocalcium phosphate monohydrate (MCPM; 3 or 6 wt%). Effects of additives on degree of monomer conversion (DC), biaxial flexural strength/modulus, shear bond strength (SBS), mass/volume change, color stability, ion release, and cytotoxicity were examined. Controls included material without reactive fillers and Panavia SA Plus (PV). Experimental cements showed higher DC than PV regardless of light activation (p<0.05). Mean SBS and color stability were comparable between experimental cements and PV. Cell viability upon the exposure to sample extracts of experimental cements was 80%-92%. High additive concentrations led to lower strength and modulus than PV (p<0.05). The additives increased mass change, reduced color stability, and promoted ion release. The experimental resin cements demonstrated acceptable mechanical/chemical properties and cytotoxicity. The additives reduced the strength but provided ion release, a desirable action to prevent recurrent caries.
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Affiliation(s)
| | - Parichart Naruphontjirakul
- Biological Engineering Program, Faculty of Engineering, King Mongkut's University of Technology Thonburi
| | | | - Bharat Mirchandani
- Faculty of Dentistry, Datta Meghe Institute of Higher Education & Research
| | - Anne M Young
- Division of Biomaterials and Tissue Engineering, UCL Eastman Dental Institute, Royal Free Hospital
| | - Piyaphong Panpisut
- Faculty of Dentistry, Thammasat University
- Thammasat University Research Unit in Dental and Bone Substitute Biomaterials, Thammasat University
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Fallahzadeh F, Pirmoradian M, Ghasemi SM, Mortazavi M. Evaluation of flexural strength, degree of conversion, and demineralization-prevention properties in adjacent tooth structures of an experimental fissure sealant containing nano-calcium-phosphate compounds. BMC Oral Health 2023; 23:906. [PMID: 37990312 PMCID: PMC10664666 DOI: 10.1186/s12903-023-03617-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 11/02/2023] [Indexed: 11/23/2023] Open
Abstract
BACKGROUND The present study aimed to evaluate the flexural strength, degree of conversion, and demineralization-prevention ability of an experimental fissure sealant containing nano-calcium-phosphate compounds. METHODS An experimental sealant was formulated using silica and nano hydroxyapatite filler particles. The control group consisted of the DENU Seal (n = 10, each group). The flexural bond strength was evaluated by UTM. DC was evaluated by FTIR. To evaluate the demineralization-prevention ability, Cl V cavities in 10 third molar teeth restored with two sealant products, followed by an acid challenge then the Vickers microhardness test was carried out. RESULTS The mean flexural strength in the commercial group was higher than the experimental group. However, the mean flexural modulus was not significantly different between the two groups. In the experimental group, DC was significantly higher than the commercial group. Adjacent to the interface, the decrease in microhardness in the experimental group was significantly less than the commercial group. However, on the tooth surface, there were no significant differences between the two groups. In the experimental group, the decrease in microhardness at the interface was less than at the tooth surface, however the situation was opposite in the commercial group. CONCLUSIONS Incorporating hydroxyapatite into the sealant structure might prevent demineralization, without adverse effects on flexural modulus and degree of conversion.
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Affiliation(s)
- Farnoosh Fallahzadeh
- Department of Operative Dentistry, Faculty of Dentistry, Qazvin University of Medical Sciences, Qazvin, Iran
| | - Maryam Pirmoradian
- Department of Dental Biomaterials, School of Dentistry/Research Center for Science and Technology in Medicine, University of Medical Sciences, Tehran, Iran
| | | | - Maryam Mortazavi
- Department of Restorative Dentistry, School of Dentistry, Birjand University of Medical Sciences, Birjand, Iran
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Musa DB, Ereifej NS. The influence of core-build up materials on biaxial flexural strength of monolithic strength-gradient zirconia; an in-vitro study. BMC Oral Health 2023; 23:873. [PMID: 37978509 PMCID: PMC10657006 DOI: 10.1186/s12903-023-03635-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 11/08/2023] [Indexed: 11/19/2023] Open
Abstract
BACKGROUND Since their introduction, there has been limited research regarding the mechanical properties of novel strength-gradient monolithic zirconia. In addition to that, studies evaluating the effect of different core-build materials on the strength of indirect restorations are scarce. Therefore, the aim of this study was to investigate the effect of using different core build-up materials on biaxial flexural strength of a new monolithic multilayered zirconia material. METHODS Forty zirconia discs were fabricated from IPS e.max ZirCAD Prime (Ivoclar Vivadent AG, Schaan, Liechtenstein) and divided into 2 groups (n = 20). Forty composite discs were prepared from Tetric N-Ceram (Ivoclar Vivadent AG, Schaan, Liechtenstein) and MultiCore Flow (Ivoclar Vivadent AG, Schaan, Liechtenstein). The zirconia discs were adhesively cemented to the 2 types of composite forming 2 groups (Zirconia-Tetric N-Ceram and Zirconia-MultiCore Flow). Biaxial flexural strength was determined using a piston-on-3-ball test. The data were statistically analyzed with an independent t-test for significant differences (p = 0.05). RESULTS Tetric N-Ceram had significantly higher strength than MultiCore Flow (p < 0.001) but no statistically significant differences were found in strength values between Zirconia-Tetric N-Ceram and Zirconia-MultiCore Flow bilayered samples (p = 0.27). CONCLUSIONS It was concluded that although the tested composite core materials significantly differ in their biaxial flexural strength values, they had no influence on the biaxial flexural strength of the overlying zirconia.
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Affiliation(s)
| | - Nadia S Ereifej
- Department of Prosthetic Dentistry, Faculty of Dentistry, The University of Jordan, Queen Rania Street, Amman, 11942, Jordan.
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Tempesta RM, Saratti CM, Rocca GT, Pasqualini D, Alovisi M, Baldi A, Comba A, Scotti N. Effects of Different Fiber-Reinforced Solutions on Fracture Strength and Pattern in Endodontically Treated Molars. INT J PROSTHODONT 2023; 36:603-611. [PMID: 33625400 DOI: 10.11607/ijp.6970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
PURPOSE To evaluate the fracture strength of endodontically treated molars filled with different composite resins with vs without fiber reinforcement. MATERIALS AND METHODS A total of 60 intact mandibular molars were selected and endodontically treated. A standardized mesio-occlusal-distal cavity was prepared with cervical margins 1 mm above the cementoenamel junction and oral and buccal walls with 1.5-mm thickness. Universal adhesive was used in all specimens in etch-and-rinse mode. Specimens were divided into four groups (n = 15 each) according to restoration technique: group CSM = adhesive overlay with hybrid ceramic; group EXP = direct restoration with short fiber-reinforced composite; group ESU = direct restoration with nanohybrid composite; and group EST = direct restoration with nanohybrid composite reinforced with horizontal bidirectional glass fibers placed over the pulpal chamber floor. After 7 days of storage in water, samples were loaded until fracture using a universal testing machine. The maximum breaking loads were recorded in Newtons, and statistical analysis was then conducted with two-way ANOVA and post hoc Tukey test. Fragments were analyzed using scanning electron microscopy. RESULTS Mean fracture resistance values were: CSM = 1,428.91 ± 316.90 N; EXP = 1,874.57 ± 299.47 N; ESU = 1,557.44 ± 355.65 N; and EST = 1,870.27 ± 145.11 N. The CSM and EXP groups showed the highest strength values when compared to the other groups. The variable fiber insertion did not significantly alter the fracture resistance. The origin of the fracture was always located on the occlusal surface, mainly in the major contact loading area. CONCLUSION The use of fiber-reinforced composite showed great improvement in fracture resistance, similar to a cuspal coverage restoration. However, only short fiber-reinforced composites showed a favorable fracture pattern. Int J Prosthodont 2023;36:603-611.
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Silva NR, Moreira FGDG, Cabral ABDC, Bottino MA, Marinho RMDM, Souza ROA. Influence of the postpolymerization type and time on the flexural strength and dimensional stability of 3D printed interim resins. J Prosthet Dent 2023; 130:796.e1-796.e8. [PMID: 37659913 DOI: 10.1016/j.prosdent.2023.07.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 07/25/2023] [Accepted: 07/27/2023] [Indexed: 09/04/2023]
Abstract
STATEMENT OF PROBLEM The mechanical strength of 3-dimensionally (3D) printed interim resins is unclear but influenced by printing parameters. Evidence regarding standardization of the postpolymerization type and time for 3D printed interim resins is sparse. PURPOSE The purpose of this in vitro study was to evaluate the influence of postpolymerization type and time on flexural strength and dimensional stability of 3D printed resins for interim restorations. MATERIAL AND METHODS A total of 288 bars were 3D printed (Form 2; Formlabs, stereolithography-SLA, 50 µm, 30 degrees), (25×2×2 mm; International Organization for Standardization-ISO 4049:2019) abraded and randomly divided into 9 groups (n=30) according to postpolymerization (Ultraviolet device-UV; Microwave with water-MWA; Microwave without water-MW) and time (15, 20, and 30 minutes for UV; and 5, 8, and 10 minutes for MW and MWA). Each bar was then measured with digital calipers at 11 points for length, thickness, and width before and after postpolymerization to analyze dimensional stability. The flexural strength was then measured (σ; 980.6 N, 1 mm/minute) and the fractured surfaces were analyzed with scanning electron microscopy. The σ (MPa) data were evaluated by using a 2-way analysis of variance (ANOVA) and the Tukey honestly significant difference (HSD) pairwise comparisons test (α=.05). Dimensional stability data (mm) were analyzed by using the Kruskal-Wallis test and Dwass-Steel-Critchlow-Fligner multiple comparisons. The Weibull analysis was performed with σ data. RESULTS The 2-way ANOVA revealed that all factors and their interaction were significant for σ (P<.001). The UV groups presented the highest σ values, being statistically higher than all MW and MWA groups. The Weibull analysis revealed that postpolymerization UV groups found the highest values regarding the characteristic strength, although the MW 8-minute group (13.71) found the highest value for the Weibull modulus. Furthermore, the Kruskal-Wallis test revealed that only the postpolymerization factor was significant for dimensional stability (P<.001). The postpolymerization microwave groups found greater expansion variations at all times, with the MW 8-minute group (0.78 ±0.54) presenting the greatest variation in dimensional stability. CONCLUSIONS UV was determined to be the most suitable type of postpolymerization for interim printed resin among the postpolymerization methods, regardless of the application time. The postpolymerization MW groups found greater variations in dimensional stability.
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Affiliation(s)
- Nathalia R Silva
- Researcher, Department of Dentistry, Federal University of Rio Grande do Norte (UFRN), Natal, RN, Brazil
| | - Fernanda G de G Moreira
- PhD student, Department of Dentistry, Federal University of Rio Grande do Norte (UFRN), Natal, RN, Brazil
| | - Ana B de C Cabral
- Researcher, Department of Dentistry, Federal University of Rio Grande do Norte (UFRN), Natal, RN, Brazil
| | - Marco A Bottino
- Professor, São Paulo State University (UNESP), Institute of Science and Technology, São Paulo, Brazil
| | - Renata M de M Marinho
- Researcher, São Paulo State University (UNESP), Institute of Science and Technology, São Paulo, Brazil
| | - Rodrigo O A Souza
- Professor, Department of Dentistry, Federal University of Rio Grande do Norte (UFRN), Natal, RN, Brazil..
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