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Elmoselhy HAS, Hassanien OES, Haridy MF, Salam El Baz MAE, Saber S. Two‑year clinical performance of indirect restorations fabricated from CAD/CAM nano hybrid composite versus lithium disilicate in mutilated vital teeth. A randomized controlled trial. BMC Oral Health 2024; 24:101. [PMID: 38233771 PMCID: PMC10792922 DOI: 10.1186/s12903-023-03847-6] [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: 10/28/2023] [Accepted: 12/31/2023] [Indexed: 01/19/2024] Open
Abstract
TRIAL DESIGN This is a randomized, controlled, superiority, double-blinded, parallel-group, two-arms trial with an allocation ratio of 1:1. The aim of this trial was to compare the two-year clinical performance of partial indirect restorations fabricated from CAD/CAM nano-hybrid composite and ceramic lithium disilicate blocks using the modified USPHS criteria. METHODS In two parallel groups (n = 50 restorations), fifty participants having mutilated vital teeth with a minimum of two remaining walls were randomly enrolled in this trial and received indirect restorations of either nano-hybrid composite resin blocks (Brilliant, Coltene, Switzerland) or Lithium Disilicate (IPS Emax CAD). The restorations were assessed using modified USPHS criteria by two independent blinded assessors at baseline, six months, one-year and two years follow-up visits. Categorical and ordinal data were presented as frequencies and percentages. Categorical data were analyzed using the chi-square test. Ordinal data were analyzed using the Mann-Whitney U test for intergroup comparisons and Freidman's test followed by the Nemenyi post hoc test for intragroup comparisons. Numerical data were presented as mean and standard deviation values. They were analyzed for normality using the Shapiro-Wilk test. Data were found to be normally distributed and were analyzed using the independent t-test. The significance level was set at p ≤ 0.05 within all tests. RESULTS Forty-eight participants received the allocated intervention and completed the follow-up periods. There was a statistically significant difference between both tested materials for all USPHS criteria regarding Marginal integrity and Marginal discoloration at six-months Follow-up, but with no statistically significant difference at one- and two-year follow-up. CONCLUSIONS Both materials showed an acceptable, successful clinical performance along the two-years follow-up period. CLINICAL RELEVANCE The CAD/CAM nano-hybrid composite blocks are as reliable as Lithium disilicate for restoring mutilated vital teeth.
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Affiliation(s)
- Haneen Ahmad Shafik Elmoselhy
- Conservative Dentistry Department, Faculty of Dentistry, The British University in Egypt, Suez Desert Road El Sherouk City, Egypt
| | | | - Mohamed Fouad Haridy
- Conservative Dentistry, Faculty of Dentistry, Cairo University and The British University in Egypt, Suez Desert Road El Sherouk City, Egypt
| | | | - Shehabeldin Saber
- Endodontics, Faculty of Dentistry, Ain Shams University and The British University in Egypt, Suez Desert Road El Sherouk City, Egypt.
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Golrezaei M, Mahgoli HA, Yaghoobi N, Niakan S. The Effect of Modified Framework Design on the Fracture Resistance of IPS e.max Press Crown after Thermocycling and Cyclic Loading. J Contemp Dent Pract 2024; 25:79-84. [PMID: 38514436 DOI: 10.5005/jp-journals-10024-3621] [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 This study aimed to investigate the effect of modified framework (MF) design on the fracture resistance of IPS e.max Press anterior single crown after thermocycling and cyclic loading. MATERIALS AND METHODS Two types of IPS e.max Press frameworks were designed (n = 10); standard framework (SF) with a 0.5 mm uniform thickness and MF with a lingual margin of 1 mm in thickness and 2 mm in height connected to a proximal strut of 4 mm height and a 0.3 mm wide facial collar. The crowns were cemented to resin dies, subjected to 5,000 cycles of thermocycling, and loaded 10,000 cycles at 100 N. A universal testing machine was used to load specimens to fracture, and the modes of failure were determined. RESULTS The mean and standard deviation (SD) of fracture resistance were 219.24 ± 110.00 N and 216.54 ±120.02 N in the SF and MF groups. Thus, there was no significant difference (p = 0.96). Mixed fracture was the most common failure mode in both groups. We found no statistically significant difference between the groups (p = 0.58). CONCLUSION The MF design did not increase the fracture resistance of IPS e.max Press crown. CLINICAL SIGNIFICANCE Framework design is an essential factor for the success of all-ceramic restorations and its modification might be regarded as an approach to increase fracture resistance. Furthermore, the modified design was evaluated in metal-ceramic or zirconia crowns while less attention was paid to the IPS e.max Press crowns. How to cite this article: Golrezaei M, Mahgoli HA, Yaghoobi N, et al. The Effect of Modified Framework Design on the Fracture Resistance of IPS e.max Press Crown after Thermocycling and Cyclic Loading. J Contemp Dent Pract 2024;25(1):79-84.
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Affiliation(s)
- Mahnaz Golrezaei
- Department of Prosthodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran
| | - Hossein Ali Mahgoli
- Department of Prosthodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran
| | - Negin Yaghoobi
- Department of Prosthodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran
| | - Somayeh Niakan
- Department of Prosthodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran, Phone: +98 9126727694, e-mail:
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Queiroz ME, Maluly-Proni AT, Tsutsumi MSC, Dallazen E, de Castro-Hoshino LV, de Souza M, Baesso ML, Dos Santos PH. Influence of thickness and degree of opacity of lithium disilicate on the degree of conversion and bond strength of resin cements. J Mech Behav Biomed Mater 2023; 143:105934. [PMID: 37257313 DOI: 10.1016/j.jmbbm.2023.105934] [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: 03/30/2023] [Revised: 05/21/2023] [Accepted: 05/21/2023] [Indexed: 06/02/2023]
Abstract
The aim of this study was to evaluate the influence of various opacities and thicknesses of lithium disilicate on the degree of conversion (DC) of two resin cements and on their bond strength (BS) to the ceramic. Two hundred and forty ceramic samples of lithium disilicate with high translucency (HT), low translucency (LT), and medium opacity (MO) were obtained from IPS e. max CAD in five different thicknesses. Light-cured and dual-cured resin cements were used for DC (n = 9) and BS (n = 8). Cement samples were light-cured under ceramic samples and analyzed using a Raman confocal spectrometer to determine the DC. For BS, resin cement cylinders were fabricated using ceramic samples which were thsen subjected to a microshear bond strength test. The mean values were provided for statistical analysis. The increase in thickness resulted in a decrease in DC for both cements under all experimental conditions, but only affected the BS of the light-cured cement for the MO ceramic. Comparing the opacities, the most translucent ceramics with particular thicknesses exhibited higher DC values than the less translucent ceramics. The LT and MO ceramics with certain thicknesses exhibited the highest BS values than the HT. The dual-cured cement generally showed highest values in both analyses than the light-cured cement. A thicker and more opaque ceramic material can reduce the DC of the cement. The BS decreases with the increasing thickness of the more-opaque ceramics.
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Affiliation(s)
- Mariana Elias Queiroz
- Department of Dental Materials and Prosthodontics, Araçatuba School of Dentistry, São Paulo State University - UNESP, Araçatuba, SP, Brazil
| | - Ana Teresa Maluly-Proni
- Department of Preventive and Restorative Dentistry, Araçatuba School of Dentistry, São Paulo State University - UNESP, Araçatuba, SP, Brazil
| | - Mariana Sati Cantalejo Tsutsumi
- Department of Preventive and Restorative Dentistry, Araçatuba School of Dentistry, São Paulo State University - UNESP, Araçatuba, SP, Brazil
| | - Eduardo Dallazen
- Department of Diagnosis and Surgery, Araçatuba School of Dentistry, São Paulo State University - UNESP, Araçatuba, SP, Brazil
| | | | - Monique de Souza
- Department of Physics, State University of Maringá - UEM, Maringá, PR, Brazil
| | | | - Paulo Henrique Dos Santos
- Department of Dental Materials and Prosthodontics, Araçatuba School of Dentistry, São Paulo State University - UNESP, Araçatuba, SP, Brazil; Dental Research Institute, University of Toronto, Faculty of Dentistry - UofT, Toronto, ON, Canada.
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Sutejo IA, Kim J, Zhang S, Gal CW, Choi YJ, Park H, Yun HS. Fabrication of color-graded feldspathic dental prosthetics for aesthetic and restorative dentistry. Dent Mater 2023:S0109-5641(23)00089-1. [PMID: 37088587 DOI: 10.1016/j.dental.2023.03.021] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 03/22/2023] [Accepted: 03/31/2023] [Indexed: 04/25/2023]
Abstract
OBJECTIVE Feasibility investigation of natural teeth shades replication on dental prosthetics fabricated via functionally graded additive manufacturing (FGAM) using combination of feldspathic porcelain (FP) and yttrium aluminum garnet cerium (Y3Al5O12:Ce, YAG:Ce) as a promising esthetic restoration option. METHODS Color-graded feldspathic crown fabrication parameter through FGAM method was comprehensively examined from the slurry rheology, cure depth, debinding to sintering temperature. Effect of light absorbent also checked towards overcuring reaction during UV exposure by the shape comparison. Lastly, the flexural bending strength measured following ISO 6872:2015 to assure the applicability. Applying the studied parameter, natural teeth shades then imitated and investigated by alteration of FP and FP + 0.1 wt% YAG:Ce (Y-FP). Generated color across the structure captured through mobile camera, interpreted through the CIELAB coordinate and the gradation confirmed by the color differences (ΔE00) calculated using CIEDE2000 formula. RESULT Parameter study indicated that 70 wt% of FP slurry with 3 wt% dispersant and 0.2 wt% light absorbent is favored. It produces excellent flowability in our FGAM system with less overcuring justified by edge margin reduction from 95.65° to 90.00° after UV exposure on rectangle shapes masking. The obtain structure also offers adequate flexural bending strength of 106.26 MPa (FP) and 101.36 MPa (Y-FP) after sintering at 780 °C. This validated the materials as class 2 dental prosthetics citing ISO 6872:2015. Color gradation was verified by the yellow b* value reduction (14.8 to -3.33) as it shifted from cervical to incisal area while ΔE00 further affirmed the differences from each segment in comparison with the FP and Y-FP. SIGNIFICANCE Color gradation was successfully replicated by FP and YAG:Ce composition shift via FGAM technique. This result highlights the potential of FGAM as an alternative for fabricating dental prosthetics with high efficiency and improved esthetic appeal.
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Affiliation(s)
- Imam Akbar Sutejo
- Korea Institute of Materials Science (KIMS), Changwon, Republic of Korea,; University of Science and Technology (UST), Daejeon, Republic of Korea
| | - Jeehwan Kim
- Korea Institute of Materials Science (KIMS), Changwon, Republic of Korea,; Pusan National University (PNU), Busan, Republic of Korea
| | - Sinuo Zhang
- Korea Institute of Materials Science (KIMS), Changwon, Republic of Korea,; University of Science and Technology (UST), Daejeon, Republic of Korea
| | - Chang Woo Gal
- Korea Institute of Materials Science (KIMS), Changwon, Republic of Korea
| | - Yeong-Jin Choi
- Korea Institute of Materials Science (KIMS), Changwon, Republic of Korea
| | - Honghyun Park
- Korea Institute of Materials Science (KIMS), Changwon, Republic of Korea
| | - Hui-Suk Yun
- Korea Institute of Materials Science (KIMS), Changwon, Republic of Korea,; University of Science and Technology (UST), Daejeon, Republic of Korea.
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Wu SY, Li YN, Zhang X, Lv LW, Liu YS, Ye HQ, Zhou YS. [Prediction, analysis and application of learning curve of tooth preparation for all ceramic crowns of maxillary central incisors]. Beijing Da Xue Xue Bao Yi Xue Ban 2023; 55:108-13. [PMID: 36718697 DOI: 10.19723/j.issn.1671-167X.2023.01.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
OBJECTIVE To predict the learning curve of tooth preparation for all ceramic crowns of maxillary central incisors on phantom head simulators for graduate students participating in standardized dental resident training based on the modified Wright learning curve model, then to analyze and applicate the learning curve. METHODS Twelve graduate students participating in standardized dental resident training were selected to prepare the resin maxillary central incisors on phantom head simulators for all ceramic crowns 4 times. The results of preparation were evaluated by 3 prosthetic experts with at least 10 years' experience focusing on the reduction, contour, taper, shoulder, finish line, margin placement, adjacent tooth injury, and preparation time for tooth preparation. The learning rate of tooth preparation was calculated by scores of tooth preparation of 4 times. The learning curve of tooth preparation was predicted based on the modified Wright learning curve model. According to the criteria of standardized training skill examinations for dental residents in Beijing, 80 was taken as the qualified standard score. The minimum training times for tooth preparation to satisfy the qualified standard score (80) was calculated, to analyze the characteristics of learning curve and evaluate the effectiveness of tooth preparation. RESULTS The scores of 4 tooth preparation were 64.03±7.80, 71.40±6.13, 74.33±5.96, and 75.98±4.52, respectively. The learning rate was (106±4)%, which showed the learning curve an upward trend. There were no significant differences between the qualified standard score and the predicted scores of tooth preparation from the 5th preparation to the 13th preparation (P > 0.05). The predicted score of the 14th preparation was higher than the qualified standard score (P < 0.05). CONCLUSION The trend of the learning curve of tooth preparation for all ceramic crowns of maxillary central incisors on phantom head simulators for graduate students participating in standardized dental resident training is upward, which predicts the minimum training times higher than the qualified standard score is 14 times.
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Zumstein K, Fiscalini L, Al-Haj Husain N, Evci E, Özcan M, Ioannidis A. Load-bearing capacity of pressable lithium disilicates applied as ultra-thin occlusal veneers on molars. J Mech Behav Biomed Mater 2022; 136:105520. [PMID: 36341889 DOI: 10.1016/j.jmbbm.2022.105520] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 10/04/2022] [Accepted: 10/07/2022] [Indexed: 11/06/2022]
Abstract
PURPOSE The aim was to investigate the load bearing capacity of different pressable lithium disilicates cemented as occlusal veneers on molars. MATERIALS AND METHODS One control group and six test groups were formed consisting of 20 specimens each (n = 20). The six test groups differed in the utilizing pressable lithium disilicate to fabricate occlusal veneers. As a control group, "group Lis", the lithium disilicate with the highest reported flexural strength was used (initial LiSi Press, GC Europe; Leuven, Belgium / flexural strength: 508 MPa). The test groups consisted of other pressable lithium disilicates with lower flexural strength values: "Ema" (IPS e.max press), "Vit" (VITA Ambria), "Liv" (Livento Press), "Amb" (Amber Press), "Mas" (Amber Press Master) and "Ros" (Rosetta SP)". After the preparation of 140 extracted human molars, which included the removal of the central enamel, the specimens were scanned using a desktop scanner. With the aid of a design software, the occlusal veneers were designed in a standardized thickness of 0.5 mm. To fabricate the restorations, all tested materials were processed using heat-pressing technique. All restorations were adhesively cemented. Afterwards, the specimens underwent cyclic fatigue during an aging procedure in a chewing simulator (1'200'000 chewing-cycles, 49 N force, 5-55°C temperature changes). Subsequently, the specimens were statically loaded and the load which was necessary to fracture the specimen (Fmax) were measured. Differences between the groups were compared applying the Kruskal-Wallis (KW) test and the Wilcoxon-Mann-Whitney-Test (WMW: p < 0.05). The two-parameter Weibull distribution values were calculated. RESULTS The fatigue resistance was 100% for the groups Lis, Vit, Liv, Amb, Mas and Ros, whereas the group Ema showed a fatigue resistance of 95%. The control group Lis showed median Fmax values of 2'328 N. The median Fmax values for the test groups ranged between 1'753 N (Vit) and 2'490 N (Ros). Statistically significant difference was observed among the groups Lis (control) and Vit (KW: p < 0.001). Weibull distribution presented the highest shape values for the group Ros (12.83) and the lowest values for the group Ema (4.71). CONCLUSION Regarding their load-bearing capacity different pressable lithium disilicates can be recommended to fabricate ultra-thin occlusal veneers on molars when restoring occlusal tooth wear.
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Affiliation(s)
- Katrin Zumstein
- University of Zurich, Center of Dental Medicine, Clinic of Reconstructive Dentistry, Zurich, Switzerland
| | - Lorenzo Fiscalini
- University of Zurich, Center of Dental Medicine, Clinic of Reconstructive Dentistry, Zurich, Switzerland
| | - Nadin Al-Haj Husain
- University of Zurich, Center of Dental Medicine, Clinic of Reconstructive Dentistry, Zurich, Switzerland; University of Bern, Department of Reconstructive Dentistry and Gerodontology, School of Dental Medicine, Bern, Switzerland
| | - Erkan Evci
- University of Zurich, Center of Dental Medicine, Clinic of Reconstructive Dentistry, Zurich, Switzerland
| | - Mutlu Özcan
- University of Zurich, Center of Dental Medicine, Clinic of Reconstructive Dentistry, Zurich, Switzerland
| | - Alexis Ioannidis
- University of Zurich, Center of Dental Medicine, Clinic of Reconstructive Dentistry, Zurich, Switzerland.
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Ahmadzadeh A, Mansourinejad S, Mansourinejad S, Rohani A. Spectrophotometric comparison of two porcelain systems, VMK master and VM13 with the VITA 3D-master shade guide (An in vitro study). Dent Res J (Isfahan) 2022; 19:35. [PMID: 35669599 PMCID: PMC9164664] [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] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 05/05/2018] [Accepted: 08/11/2021] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Accurate shade matching of metal-ceramic restorations with natural teeth is one of the most challenging aspects of dental restorations and esthetic dentistry. The aim of this study was to evaluate of the color parameters of two types of porcelain systems VMK Master and VM13 porcelain with VITA 3D-master shade guide. MATERIALS AND METHODS In this in vitro study a total of 56 metal discs (10 mm diameter and 2 mm thickness) were fabricated. Each of the disks was veneered with porcelain (Vita Zahnfabrik, Bad Sackingen, Germany) of the VITA shade. The discs were randomly divided into four groups (2M2 and 3M2 from VM13, 2M2 and 3M2 from VMK master) of 14 (n = 14). The spectrophotometer was used for taking color measurements based on the numerical color data of the CIELAB color system. Data analysis was performed by t-test (P < 0.05). RESULTS Comparison of color parameters in different porcelain showed that the type of porcelain caused a significant difference in color parameters (L, a, and b) (P < 0.05). The degree of translucency (L*) or glaze of VMK porcelains was higher than VM13, but the parameters a* and b* were higher in VM13 porcelains than VMK (P < 0.05). Furthermore, the color difference of two porcelain in 2M2 (1.63 ± 0.84) and 3M2 (1.71 ± 0.96) shades was within the acceptable clinical limit. Considering the total color difference (ΔE), there were no significant differences between the ΔE values produced by any of shades (P > 0.05). CONCLUSION In the present study, the spectrophotometric analysis revealed that the porcelain shade type causes a change in the color parameters, but the color difference between two porcelains VMK and VM13 is within the acceptable range of clinical color. Therefore, both porcelain systems with 2M2 and 3M2 shades are suitable for enhancing the results of restorative dentistry.
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Affiliation(s)
- Assadollah Ahmadzadeh
- Department of Prosthodontics, School of Dentistry, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Sara Mansourinejad
- Department of Prosthodontics, School of Dentistry, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran,Address for correspondence: Dr. Sara Mansourinejad, Department of Prosthodontics, School of Dentistry, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. E-mail:
| | - Sanaz Mansourinejad
- Department of Prosthodontics, School of Dentistry, Qazvin University of Medical Sciences, Qazvin, Iran
| | - Ali Rohani
- Department of Prosthodontics, School of Dentistry, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
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Marcondes RL, Lima VP, Isolan CP, Lima GS, Moraes RR. Ceramic Laminate Veneers Luted with Preheated Resin Composite: A 10-Year Clinical Report. Contemp Clin Dent 2021; 12:313-316. [PMID: 34759691 PMCID: PMC8525818 DOI: 10.4103/ccd.ccd_788_20] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 10/10/2020] [Accepted: 10/25/2020] [Indexed: 11/20/2022] Open
Abstract
Resin cement and preheated restorative resin composite may be used for luting laminate veneers. The main advantage of resin composite is increased wear resistance, which could lead to better marginal performance in long term. This article reports a clinical treatment with feldspar laminate veneers luted to the maxillary teeth with preheated resin composite in a private practice. Case was finalized in May 2009 and followed by 10 years. Excellent clinical service and remarkable long-lasting marginal integrity were observed after 123 months. Scanning electron microscopy analysis showed no wear, gaps, or ditching at the margins. Restorative margins showed a smooth transition between ceramic and tooth with no signs of degradation. Preheated resin composite for luting ceramic laminate veneers may be considered an excellent clinical option.
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Affiliation(s)
- Rogério L Marcondes
- Private Practice, Curitiba, PR, Pelotas, RS, Brazil.,Graduate Program in Dentistry, Federal University of Pelotas, Pelotas, RS, Brazil
| | - Verônica P Lima
- Graduate Program in Dentistry, Federal University of Pelotas, Pelotas, RS, Brazil
| | - Cristina P Isolan
- Graduate Program in Dentistry, Federal University of Pelotas, Pelotas, RS, Brazil
| | - Giana S Lima
- Graduate Program in Dentistry, Federal University of Pelotas, Pelotas, RS, Brazil
| | - Rafael R Moraes
- Graduate Program in Dentistry, Federal University of Pelotas, Pelotas, RS, Brazil
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Grassi EDA, de Andrade GS, Tribst JPM, Machry RV, Valandro LF, Ramos NDC, Bresciani E, Saavedra GDSFA. Fatigue behavior and stress distribution of molars restored with MOD inlays with and without deep margin elevation. Clin Oral Investig 2021; 26:2513-2526. [PMID: 34643807 DOI: 10.1007/s00784-021-04219-6] [Citation(s) in RCA: 3] [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: 06/10/2021] [Accepted: 10/04/2021] [Indexed: 11/26/2022]
Abstract
OBJECTIVES This study evaluated the effect of deep margin elevation (DME) and restorative materials (leucite-reinforced glass-ceramics [C] vs. indirect resin composite [R]) on the fatigue behavior and stress distribution of maxillary molars with 2-mm deep proximal margins restored with MOD inlay. METHODS Fifty-two extracted human third molars were randomly assigned into four groups (n = 13): C; DME + C; R; and DME + R. Inlays were fabricated in CAD-CAM and bonded to all teeth. The fatigue behavior was assessed with the stepwise stress test (10,000 cycles/step; step = 50 N; 20 Hz; initial load = 200 N). Fatigue failure loads and the number of cycles were analyzed with 2-way ANOVA and Tukey's test (p < 0.05) and Kaplan-Meier survival plots. The stress distribution was assessed with finite element analysis. The models were considered isotropic, linear, and homogeneous, and presented bonded contacts. A tripod axial load (400 N) was applied to the occlusal surface. The stress distribution was analyzed with the maximum principal stress criterion. RESULTS For fatigue, there was no difference for DME factor (p > 0.05). For the material factor, the load and number of cycles for failure were statistically higher in the R groups (p < 0.05). The finite element analysis showed that resin composite inlays concentrated more stress in the tooth structure, while ceramic inlays concentrated more stress in the restoration. Non-reparable failures were more frequent in the resin composite inlays groups. CONCLUSIONS DME was not negative for fatigue and biomechanical behaviors. Resin composite inlays were more resistant to the fatigue test, although the failure mode was more aggressive. CLINICAL SIGNIFICANCE DME does not impair mechanical behavior. Resin composite inlays failed at higher loads but with a more aggressive failure mode.
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Affiliation(s)
- Elisa Donaria Aboucauch Grassi
- Department of Dental Materials and Prosthodontics, Institute of Science and Technology, São Paulo State University (Unesp), 777th Eng. Francisco José Longo Av., São José dos Campos, SP, 12245-000, Brazil
| | - Guilherme Schmitt de Andrade
- Department of Dental Materials and Prosthodontics, Institute of Science and Technology, São Paulo State University (Unesp), 777th Eng. Francisco José Longo Av., São José dos Campos, SP, 12245-000, Brazil
| | - João Paulo Mendes Tribst
- Post-Graduate Program in Dentistry, University of Taubaté (UNITAU), 09th Rua Dos Operários St., Taubaté, SP, 12020-340, Brazil
| | - Renan Vaz Machry
- Graduate Program of Oral Science, Prosthodontics Unit, School of Dentistry, Federal University of Santa Maria (UFSM), Roraima Av, Santa Maria, RS, 100097105-340, Brazil
| | - Luiz Felipe Valandro
- Graduate Program of Oral Science, Prosthodontics Unit, School of Dentistry, Federal University of Santa Maria (UFSM), Roraima Av, Santa Maria, RS, 100097105-340, Brazil
| | - Nathalia de Carvalho Ramos
- School of Dentistry, São Francisco University (USF), 218th São Francisco de Assis Av., Bragança Paulista, SP, 12916-900, Brazil
| | - Eduardo Bresciani
- Department of Restorative Dentistry, Institute of Science and Technology, São Paulo State University (Unesp), 777th Eng. Francisco José Longo Av., São José dos Campos, SP, 12245-000, Brazil
| | - Guilherme de Siqueira Ferreira Anzaloni Saavedra
- Department of Dental Materials and Prosthodontics, Institute of Science and Technology, São Paulo State University (Unesp), 777th Eng. Francisco José Longo Av., São José dos Campos, SP, 12245-000, Brazil.
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Rani V, Mittal S, Sukhija U. An In vitro Evaluation to Compare the Surface Roughness of Glazed, Reglazed and Chair Side Polished Surfaces of Dental Porcelain. Contemp Clin Dent 2021; 12:164-168. [PMID: 34220157 PMCID: PMC8237812 DOI: 10.4103/ccd.ccd_86_20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 04/17/2020] [Accepted: 08/13/2020] [Indexed: 12/05/2022] Open
Abstract
Aim: The aim of this study was to evaluate the effect of glazing, reglazing, and chairside polishing on the surface roughness of dental porcelain. Materials and Methods: A total of 50 discs of feldspathic porcelain were fabricated using a metal mold of dimension 10 mm × 2 mm. Based on the surface treatment, the samples were divided into five groups. Group A – Glazed (control), Group B – Abraded and reglazed, Group C – Abraded and polished with porcelain adjustment kit (Shofu Dental Corp. PN 0301 Classic Plastic HP Kit, Shofu Inc., Kyoto, Japan), Group D – Abraded and polished with diamond polishing paste (Shofu Dental Corp. PN 0558 DirectDia, Shofu Inc., Kyoto, Japan), Group E-Abraded and polished with the combination of porcelain adjustment kit followed by diamond polishing paste. The surface roughness (Ra) values (μm) were evaluated by a profilometer (Mitutoyo Surftest SJ-310, Tokyo, Japan). The data obtained were statistically analyzed using one-way ANOVA and post hoc Tukey's test. Results: The mean surface roughness (Ra) of Groups A, B, C, D, and E was 0.567 ± 0.078 μm, 0.433 ± 0.059 μm, 0.882 ± 0.126 μm, 2.361 ± 0.195 μm, and 0.438 ± 0.043 μm, respectively. The samples of Group D (Polished with polishing paste alone) had the highest surface roughness (Ra value). Whereas the samples of Group B and E had similar surface roughness (Ra) value. Differences between Groups A, B, and E were statistically insignificant (P > 0.05). Conclusion: After adjustment of ceramic restorations in dental clinics, diamond polishing paste, when used after porcelain adjustment kit, could provide the marked finish equal to glazed or reglazed surface.
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Affiliation(s)
- Varsha Rani
- Department of Prosthodontics and Crown and Bridge, Maharishi Markadeshwar College of Dental Science and Research, Mullana, Ambala, Haryana, India
| | - Sanjeev Mittal
- Department of Prosthodontics and Crown and Bridge, Maharishi Markadeshwar College of Dental Science and Research, Mullana, Ambala, Haryana, India
| | - Urvashi Sukhija
- Department of Prosthodontics and Crown and Bridge, Maharishi Markadeshwar College of Dental Science and Research, Mullana, Ambala, Haryana, India
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Jurado CA, Fischer NG, Mourad F, Villalobos-Tinoco J, Tsujimoto A. Conservative Ultrathin Veneer Restorations with Minimal Reduction: A 5-year Follow-up Report. J Contemp Dent Pract 2020; 21:1293-1297. [PMID: 33850078] [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] [Indexed: 06/12/2023]
Abstract
AIM AND OBJECTIVE This case report shows how a feldspathic veneer with diagnostic wax-ups, subsequent mock-up, and reduction guides can lead to good patient esthetics and reports a 5-year follow-up. BACKGROUND Conservative tooth preparation is important for the long-term success of adhesive dentistry as it has been shown that bonding to enamel is more predictable in obtaining better long-term success than dentin. To preserve enamel for optimal bonding, diagnostic wax-ups and the subsequent mock-up are the first tools in a restorative dentist's arsenal to find and address differences between current and ideal tooth proportions and also help toward an overall conservative approach. Reduction guides are recommended in order to provide adequate tooth reduction and prevent over-reduction. CASE DESCRIPTION This case report shows a 5-year follow-up of feldspathic veneer restorations for a patient with excessive space among teeth, defective composite restorations on facial and incisal surfaces, and worn teeth. Veneers were delivered with conservative tooth preparation combining different tooth reduction guides. CONCLUSION This case report highlights the added benefits of tooth reduction guides and diagnostic wax-ups and the subsequent mock-up for long-term patient satisfaction. CLINICAL SIGNIFICANCE Conservative tooth preparation, reduction guides, and wax-ups may increase the life span of veneer restorations and demonstrate good esthetics at 5 years.
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Affiliation(s)
- Carlos A Jurado
- Clinical Digital Dentistry, AT Still University Arizona School of Dentistry and Oral Health, Mesa, Arizona, USA
| | - Nicholas G Fischer
- Minnesota Dental Research Center for Biomaterials and Biomechanics, University of Minnesota School of Dentistry, Minneapolis, Minnesota, USA, Phone: +1 612-625-0950, e-mail:
| | - Firas Mourad
- Department of Care Planning and Restorative Sciences, University of Mississippi Medical Center School of Dentistry, Jackson, Mississippi, USA
| | - Jose Villalobos-Tinoco
- Department of Oral Rehabilitation. Autonomous University of Queretaro School of Dentistry, Queretaro, Queretaro, Mexico
| | - Akimasa Tsujimoto
- Department of Operative Dentistry, Nihon University School of Dentistry, Tokyo, Japan
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Machado PS, Pereira GKR, Rodrigues CDS, Guilardi LF, Valandro LF, Rippe MP. Fatigue behavior and colorimetric differences of a porcelain-veneered zirconia: effect of quantity and position of specimens during firing. J Prosthodont Res 2020; 65:202-207. [PMID: 33028795 DOI: 10.2186/jpr.jpor_2019_336] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
PURPOSE To evaluate the influence of quantity and positioning of veneered zirconia specimens during firing of porcelain on their fatigue performance and colorimetric differences. METHODS Bilayer discs (Ø=15 mm) were made, following ISO 6872 guidelines, using a Y-TZP core (yttria-stabilized tetragonal zirconia polycrystal ceramic; VITA In-Ceram YZ) and a feldspathic veneering material (VITA VM9), being both layers with 0.7 mm thickness. Y-TZP discs were sintered, the veneering material was applied over it, and the bilayer specimens were fired according to two factors (n=20): 'quantity' (1 or 5 samples per firing cycle; G1 and G5 groups respectively) and 'positioning' of the specimens inside the furnace (center or periphery of the refractory tray; G5C and G5P groups, respectively). The CIEL*a*b* parameters were recorded with a spectrophotometer and the color difference (ΔE 00 ) and translucency (TP 00 ) were calculated using CIEDE2000 equations. The step-stress fatigue test was performed with the veneer facing down (region of tensile stress concentration), 10 Hz frequency, initial tension of 20 MPa for 5,000 cycles, followed by steps of 10,000 cycles using a step size of 10 MPa, up to 100 MPa; data from strength and number of cycles for failure were recorded for statistical analysis. RESULTS Unacceptable color differences (ΔE 00 >1.8) were observed comparing G5C vs. G1 (quantity) and G5C vs. G5P (positioning), meanwhile translucency parameters were not affected. Besides, only the 'quantity' factor influenced the fatigue performance (G1>G5C). None of the tested specimens survived beyond 90N and/or 75000 cycles. CONCLUSIONS The quantity and position of the specimens during firing influence the final color of porcelain-veneered zirconia, and firing one specimen per cycle improved the fatigue performance of the bilayer system.
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Affiliation(s)
- Pablo Soares Machado
- Post-Graduate Program in Oral Sciences (Prosthodontics Units), Faculty of Odontology, Federal University of Santa Maria (UFSM), Santa Maria
| | - Gabriel Kalil Rocha Pereira
- Post-Graduate Program in Oral Sciences (Prosthodontics Units), Faculty of Odontology, Federal University of Santa Maria (UFSM), Santa Maria
| | - Camila da Silva Rodrigues
- Post-Graduate Program in Oral Sciences (Prosthodontics Units), Faculty of Odontology, Federal University of Santa Maria (UFSM), Santa Maria
| | - Luís Felipe Guilardi
- Post-Graduate Program in Oral Sciences (Prosthodontics Units), Faculty of Odontology, Federal University of Santa Maria (UFSM), Santa Maria
| | - Luiz Felipe Valandro
- Post-Graduate Program in Oral Sciences (Prosthodontics Units), Faculty of Odontology, Federal University of Santa Maria (UFSM), Santa Maria
| | - Marília Pivetta Rippe
- Post-Graduate Program in Oral Sciences (Prosthodontics Units), Faculty of Odontology, Federal University of Santa Maria (UFSM), Santa Maria
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Ioannidis A, Bomze D, Hämmerle CHF, Hüsler J, Birrer O, Mühlemann S. Load-bearing capacity of CAD/CAM 3D-printed zirconia, CAD/CAM milled zirconia, and heat-pressed lithium disilicate ultra-thin occlusal veneers on molars. Dent Mater 2020; 36:e109-16. [PMID: 31992483 DOI: 10.1016/j.dental.2020.01.016] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2019] [Revised: 12/19/2019] [Accepted: 01/14/2020] [Indexed: 11/22/2022]
Abstract
OBJECTIVES The load-bearing capacity of ultra-thin occlusal veneers made of 3D-printed zirconia were compared to the ones obtained by fabricating these reconstructions by CAD/CAM milling zirconia or heat-pressing lithium-disilicate. METHODS On 60 extracted human molars, the occlusal enamel was removed and extended into dentin. Occlusal veneers of 0.5 mm thickness were digitally designed. The specimens were divided into 3 groups (n = 20 each) differing in the restorative material and the fabrication technique of the occlusal veneer. (1) 3DP: 3D-printed zirconia (Lithoz); (2): CAM: milled zirconia (Ceramill Zolid FX); (3) HPR: heat-pressed lithium disilicate (IPS e.max Press). After conditioning procedures, the restorations were adhesively bonded onto the conditioned tooth. Thereafter, all specimens were aged in a chewing simulator by exposure to cyclic fatigue and temperature variations. Subsequently the specimens were statically loaded and the load which was necessary to decrease the maximum load by 20% and initiate a crack (Finitial) and the load which was needed to fracture the specimen (Fmax) were measured. Differences between the groups were compared applying the Kruskal-Wallis (KW) test and the Wilcoxon-Mann-Whitney-Test (WMW: p < 0.05). RESULTS The median Finitial values for the groups 3DP, CAM and HPR were 1'650 N, 1'250 N and 500 N. The differences between all three groups were statistically significant (KW: p < 0.0001). The median Fmax values amounted to 2'026 N for the group 3DP, 1'500 N for the group CAM and 1'555 N for the group HPR. Significant differences were found between 3DP and CAM (WMW: p = 0.0238). SIGNIFICANCE Regarding their load-bearing capacity, 3D-printed or milled zirconia as well as heat-pressed lithium disilicate can be recommended as restorative material for ultra-thin occlusal veneers to prosthetically compensate for occlusal tooth wear. Despite statistically significant differences between the restoration materials, all load-bearing capacities exceeded the clinically expected normal bite forces.
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Society of Esthetic Dentistry, Chinese Stomatological Association. [Expert consensus on clinical application of all-ceramic esthetic restorative materials]. Zhonghua Kou Qiang Yi Xue Za Zhi 2019; 54:825-8. [PMID: 31874482 DOI: 10.3760/cma.j.issn.1002-0098.2019.12.007] [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: 06/10/2023]
Abstract
All-ceramic materials have become the most commonly used dental esthetic restorative material in clinic due to their excellent esthetic and mechanical properties and biocompatibility. However, there are still many confusions about the clinical application of all-ceramic materials. Society of Esthetic Dentistry in conjunction with Society of Dental Material Science, Chinese Stomatological Association organized multidisciplinary experts in prosthodontics, dental materials, implantology and dental esthetics to develop a consensus on the clinical application of all-ceramic esthetic restorative materials. The expert consensus covers such aspects of all-ceramic materials as the classification, major properties, selection of clinical indications and treatment of bonding interfaces. It is hoped that the consensus may help the clinicians to make correct decisions in selecting adequate materials in all-ceramic restoration according to various specific cases in the clinic.
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Ahmadzadeh A, Ghanavati S. Comparison of bond strength of two porcelains and two base metal alloys in metal-ceramic restorations. Dent Res J (Isfahan) 2019; 16:298-303. [PMID: 31543935 PMCID: PMC6749861] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND The purpose of this study was to evaluate the bond strength between two porcelains (VITA VMK Master and VITA VM13) and two types of base metal alloys (Ceramill Sintron and Verabond). MATERIALS AND METHODS In an experimental study, 20 rectangular strips (25 mm × 4 mm × 0.5 mm) of each base metal alloy (Ceramill Sintron and Verabond) were fabricated according to the manufacturer's instructions. After sandblasting and polishing, the samples were placed in an ultrasonic device to remove surface contaminants. A surface of 8 mm × 4 mm × 1 mm of samples was veneered with Vita VM13 and VITA VMK Master. The samples were divided into four groups (n = 10 each group; VM13/Ceramill, VMK Master/Ceramill, VM13/Verabond, and VMK Master/Verabond), and bond strength was evaluated by three-point bending test with a universal testing machine. Two-way ANOVA was used for comparison in each group, post hoc Scheffe's test was used for analyzing data between groups, and the Kolmogorov-Smirnov test was used for the normality (P < 0.05). RESULTS The maximum bond strength was related to Verabond/VM13 (44.35 ± 7.9 MPa) and then the Ceramill Sintron/VM13 (39.33 ± 4.43 MPa), and the lowest was related to the Ceramill Sintron/VMK Master (29.75 ± 3.2 MPa). There was no significant difference between bond strength of VM13 with the two alloy groups (P > 0.05), and bond strength of VMK Master to Ceramill Sintron CAD/CAM alloy was less than the conventional Verabond alloy (P < 0.05); however, bond strength of all the groups was above the standard threshold (25 MPa). CONCLUSION Based on the results of this study, the bond strength of the porcelain to Verabond was better, but the bond strength of the porcelain to Ceramill Sintron also was not less than the standard threshold; thus, this new CAD/CAM alloy can be an alternative to the conventional base metal alloys in the metal-ceramic restorations.
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Affiliation(s)
- Asadollah Ahmadzadeh
- Department of Prosthodontics, Dental School, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Saghar Ghanavati
- Department of Prosthodontics, Dental School, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran,Address for correspondence: Dr. Saghar Ghanavati, Department of Prosthodontics, Dental School, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. E-mail:
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Abstract
Introduction: Bracket bonding to porcelain has high failure rate compared to bonding to enamel. Aim: This study aimed to assess the shear bond strength (SBS) of metal brackets to porcelain using a universal adhesive. Material and Methods: In this in vitro experimental study, 40 porcelain blocks (1x1x1 cm3)were divided into four groups (n=10). The porcelain surfaces were etched with 10% hydrofluoric (HF) acid and bonded to metal brackets using Transbond XT composite and the following bonding protocols: Transbond XT bonding agent alone in group 1, silane plus Transbond XT bonding agent in group 2, silane plus universal adhesive (G-Premio bond) in group 3 and universal adhesive alone in group 4. The SBS was measured using a universal testing machine at a crosshead speed of 1 mm/minute. Fracture surfaces were evaluated under a stereo microscope, and the adhesive remnant index (ARI) scores were determined. Results: The highest and the lowest SBS values were noted in groups 3 (17.06±2.58 MPa) and 4 (9.85±4.76 MPa), respectively. Type of adhesive had no significant effect on SBS (P=0.611). However, the effect of application of silane on SBS was significant (P=0.000). Groups subjected to the application of silane showed higher SBS values than others. The mode of failure was mainly adhesive in groups 2 and 3, and adhesive and mixed in groups 1 and 4. The difference in ARI scores was statistically significant (P=0.016). Conclusion: Universal adhesive and Transbond XT were not significantly different in SBS. However, application of silane significantly increased the bond strength.
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Affiliation(s)
- Amin Golshah
- Department of Orthodontics, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Nahid Mohamadi
- Students Research Committee, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Farshad Rahimi
- Department of Orthodontics, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Hoda Pouyanfar
- Department of Restorative Dentistry, Dental Faculty, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | | | - Mohammad Moslem Imani
- Department of Orthodontics, Kermanshah University of Medical Sciences, Kermanshah, Iran
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Alfrisany NM, Shokati B, Tam LE, De Souza GM. Simulated occlusal adjustments and their effects on zirconia and antagonist artificial enamel. J Adv Prosthodont 2019; 11:162-168. [PMID: 31297175 PMCID: PMC6609759 DOI: 10.4047/jap.2019.11.3.162] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 03/26/2019] [Accepted: 06/11/2019] [Indexed: 11/29/2022] Open
Abstract
PURPOSE The aim of this study was to evaluate the effect of occlusal adjustments on the surface roughness of yttria-tetragonal zirconia polycrystal (Y-TZP) and wear of opposing artificial enamel. MATERIALS AND METHODS Twenty-five Y-TZP slabs from each brand (Lava, 3M and Bruxzir, Glidewell Laboratories) with different surface conditions (Control polished - CPZ; Polished/ground - GRZ; Polished/ground/repolished - RPZ; Glazed - GZ; Porcelain-veneered - PVZ; n=5) were abraded (500,000 cycles, 80 N) against artificial enamel (6 mm diameter steatite). Y-TZP roughness (in µm) before and after chewing simulation (CS) and antagonist steatite volume loss (in mm3) were evaluated using a contact surface profilometer. Y-TZP roughness was analyzed by three-way analysis of variance (ANOVA) and teatite wear by two-way ANOVA and Tukey Honest Difference (HSD) (P=.05). RESULTS There was no effect of Y-TZP brand on surface roughness (P=.216) and steatite loss (P=.064). A significant interaction effect (P<.001) between surface condition and CS on Y-TZP roughness was observed. GZ specimens showed higher roughness after CS (before CS − 3.7 ± 1.8 µm; after CS − 13.54 ± 3.11 µm), with partial removal of the glaze layer. Indenters abraded against CPZ (0.09 ± 0.03 mm3) were worn more than those abraded against PVZ (0.02 ± 0.01 mm3) and GZ (0.02 ± 0.01 mm3). Higher wear caused by direct abrasion against zirconia was confirmed by SEM. CONCLUSION Polishing with an intraoral polishing system did not reduce the roughness of zirconia. Wear of the opposing artificial enamel was affected by the material on the surface rather than the finishing technique applied, indicating that polished zirconia is more deleterious to artificial enamel than are glazed and porcelain-veneered restorations.
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Affiliation(s)
- Najm Mohsen Alfrisany
- Department of Dental Health, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia.,Faculty of Dentistry, University of Toronto, Toronto, Canada
| | - Babak Shokati
- Faculty of Dentistry, University of Toronto, Toronto, Canada
| | - Laura Eva Tam
- Faculty of Dentistry, University of Toronto, Toronto, Canada
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Jikihara AN, Tanaka CB, Ballester RY, Swain MV, Versluis A, Meira JBC. Why a zero CTE mismatch may be better for veneered Y-TZP structures. J Mech Behav Biomed Mater 2019; 96:261-268. [PMID: 31075747 DOI: 10.1016/j.jmbbm.2019.04.049] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 04/25/2019] [Accepted: 04/26/2019] [Indexed: 10/26/2022]
Abstract
OBJECTIVE Compare residual stress distribution of bilayered structures with a mismatch between the coefficient of thermal expansion (CTE) of framework and veneering ceramic. A positive mismatch, which is recommended for metal-ceramic dental crowns, was hypothesized to contribute to a greater chipping frequency in veneered Y-TZP structures. In addition, the multidirectional nature of residual stresses in bars and crowns is presented to explore some apparent contradictions among different studies. METHODS Planar bar and crown-shaped bilayered specimens with 0.7 mm framework thickness and 1.5 mm porcelain veneer thickness were investigated using finite element elastic analysis. Eight CTE mismatch conditions were simulated, representing two framework materials (zirconia and metal) and six veneering porcelains (distinguished by CTE values). Besides metal-ceramic and zirconia-ceramic combinations indicated by the manufacturer, models presenting similar mismatch values (1 ppm/°C) with different framework materials (metal or zirconia) and zirconia-based models with metal-compatible porcelain veneers were also tested. A slow cooling protocol from 600 °C to room temperature was simulated. The distributions of residual maximum and minimum principal stresses, as well as stress components parallel to the long axis of the specimens, were analysed. RESULTS Planar and crown specimens generated different residual stress distributions. When manufacturer recommended combinations were analysed, residual stresses obtained for zirconia models were significantly higher than those for metal-based models. When zirconia frameworks were combined with metal-compatible porcelains, the residual stress values were even higher. Residual stresses were not different between metal-based and zirconia-based models if the CTE mismatch was similar. SIGNIFICANCE Some conclusions obtained with planar specimens cannot be extrapolated to clinical situations because specimen shape strongly influences residual stress patterns. Since positive mismatch generates compressive hoop stresses and tensile radial stresses and since zirconia-based crowns tend to be more vulnerable to chipping, a tensile stress-free state generated with a zero CTE mismatch could be advantageous.
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Affiliation(s)
- Alice N Jikihara
- Department of Biomaterials and Oral Biology, School of Dentistry, University of São Paulo, São Paulo, Brazil
| | - Carina B Tanaka
- School of Mechanical and Manufacturing Engineering, UNSW, Sydney, NSW, Australia
| | - Rafael Y Ballester
- Department of Biomaterials and Oral Biology, School of Dentistry, University of São Paulo, São Paulo, Brazil
| | - Michael V Swain
- Bioengineering, AMME, Faculty of Engineering, University of Sydney, Sydney, NSW, Australia
| | - Antheunis Versluis
- Department of Bioscience Research, College of Dentistry, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Josete B C Meira
- Department of Biomaterials and Oral Biology, School of Dentistry, University of São Paulo, São Paulo, Brazil.
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Maeder M, Pasic P, Ender A, Özcan M, Benic GI, Ioannidis A. Load-bearing capacities of ultra-thin occlusal veneers bonded to dentin. J Mech Behav Biomed Mater 2019; 95:165-171. [PMID: 31009900 DOI: 10.1016/j.jmbbm.2019.04.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 04/08/2019] [Accepted: 04/09/2019] [Indexed: 10/27/2022]
Abstract
OBJECTIVES To test whether the load-bearing capacity of occlusal veneers made of ceramic or hybrid materials bonded to dentin does differ from those of porcelain-fused-to metal or lithium disilicate glass ceramic crowns. MATERIAL AND METHODS In 80 human molars, occlusal tooth substance was removed so that the defects extended into dentin, simulating defects caused by attrition/erosion. Restorations at a standardized thickness of either 0.5 mm or 1.0 mm were digitally designed. For both thicknesses, 4 test groups (n = 10 per group) were defined, each including a different restorative material: "0.5-ZIR": 0.5 mm thick zirconia (Vita YZ HT); "1.0-ZIR": 1.0 mm thick zirconia (Vita YZ HT); "0.5-LDC": 0.5 mm thick lithium disilicate ceramic (IPS e.max Press); "1.0-LDC": 1.0 mm thick lithium disilicate ceramic (IPS e.max Press); "0.5-HYC": 0.5 mm thick PICN (Vita Enamic); "1.0-HYC": 1.0 mm thick PICN (Vita Enamic); "0.5-COC": 0.5 mm thick tooth shaded resin composite (Lava Ultimate) and "1.0-COC": 1.0 mm thick tooth shaded resin composite (Lava Ultimate). Consecutively, the specimens were thermo-mechanically aged and then loaded until fracture. The load-bearing capacities (Fmax) between the groups were statistically compared using the Kruskal-Wallis test (p < 0.05) and pairwise group comparison applying the Dunn's method. In addition, the results were compared to those of conventional lithium-disilicate ceramic crowns ("CLD") and to porcelain-fused to metal crowns ("PFM"). RESULTS The median Finitial values for the 0.5 mm thin restorations were 1'350 N for 0.5-ZIR, 850 N for 0.5-LDC, 1'100 N for 0.5-HYC and 1'950 N for 0.5-COC. With CLD as the control, a significant difference was found between the groups 0.5-COC and 0.5-LDC (KW: p = 0.0124). With PFM as the control, the comparisons between PFM and 0.5-LDC as well as between 0.5-COC and 0.5-LDC were significant (KW: p = 0.0026). Median Fmax values of 2'493 N in the group 0.5-ZIR, 1'165 in the group 0.5-LDC, 2'275 N in the group 0.5-HYC and 2'265 N in the group 0.5-COC were found. The medians of the Finitial values for the 1.0 thick restorations amounted of 2'100 N in 1.0-ZIR, 1'750 N in 1.0-LDC, 2'000 N in 1.0-HYC and 2'300 N in 1.0-COC. Testing the multiple comparisons with Dunn's method no significant differences were found (p > 0.05). The median Fmax values of the 1.0 mm thick restorations were: 2'489 N in the group 1.0-ZIR, 1'864 N in the group 1.0-LDC, 2'485 N in the group 1.0-HYC and 2'479 N in the group 1.0-COC. With CLD as the control group, a significant difference between zirconia and lithium-disilicate was found for the 0.5 (p = 0.0017) and 1.0 mm (p = 0.0320) thick specimens. Comparing the 0.5 mm thick specimens with CLD as the control, a significant difference was found between 0.5-HYC and 0.5-LDC (p = 0.0017). With PFM as the control, the comparison of lithium disilicate and zirconia was statistically significant for both thicknesses (p = 0.0009 for the 0.5 mm thick specimens; p = 0.0074 for the 1.0 mm thick specimens). In addition, with PFM as control group, significant differences were seen between 0.5-LDC and all other groups with restorations in 0.5 mm thickness (p = 0.0017). CONCLUSIONS Regarding their maximum load-bearing capacity, minimally invasive occlusal veneers made of ceramic, hybrid materials or polymeric materials can be applied to correct occlusal tooth wear with exposed dentin and thus replace conventional crown restorations in cases of normally expected intraoral bite forces.
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Affiliation(s)
- Mila Maeder
- Doctoral Student at the Clinic of Fixed and Removable Prosthodontics and Dental Material Science, Center of Dental Medicine, University of Zurich, Switzerland
| | - Pavla Pasic
- Doctoral Student at the Clinic of Fixed and Removable Prosthodontics and Dental Material Science, Center of Dental Medicine, University of Zurich, Switzerland
| | - Adreas Ender
- Clinic of Preventive Dentistry, Periodontology and Cariology, Center of Dental Medicine, University of Zurich, Switzerland
| | - Mutlu Özcan
- Clinic of Fixed and Removable Prosthodontics and Dental Material Science, Center of Dental Medicine, University of Zurich, Switzerland
| | - Goran I Benic
- Clinic of Fixed and Removable Prosthodontics and Dental Material Science, Center of Dental Medicine, University of Zurich, Switzerland
| | - Alexis Ioannidis
- Clinic of Fixed and Removable Prosthodontics and Dental Material Science, Center of Dental Medicine, University of Zurich, Switzerland.
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Lunt AJG, Chater P, Kleppe A, Baimpas N, Neo TK, Korsunsky AM. Residual strain mapping through pair distribution function analysis of the porcelain veneer within a yttria partially stabilised zirconia dental prosthesis. Dent Mater 2018; 35:257-269. [PMID: 30502963 DOI: 10.1016/j.dental.2018.11.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 10/31/2018] [Accepted: 11/14/2018] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Residually strained porcelain is influential in the early onset of failure in Yttria Partially Stabilised Zirconia (YPSZ) - porcelain dental prosthesis. In order to improve current understanding it is necessary to increase the spatial resolution of residual strain analysis in these veneers. METHODS Few techniques exist which can resolve residual stress in amorphous materials at the microscale resolution required. For this reason, recent developments in Pair Distribution Function (PDF) analysis of X-ray diffraction data of dental porcelain have been exploited. This approach has facilitated high-resolution (70μm) quantification of residual strain in a YPSZ-porcelain dental prosthesis. In order to cross-validate this technique, the sequential ring-core focused ion beam and digital image correlation approach was implemented at a step size of 50μm. This semi-destructive technique exploits microscale strain relief to provide quantitative estimates of the near-surface residual strain. RESULTS The two techniques were found to show highly comparable results. The residual strain within the veneer was found to be primarily tensile, with the highest magnitude stresses located at the YPSZ-porcelain interface where failure is known to originate. Oscillatory tensile and compressive stresses were also found in a direction parallel to the interface, likely to be induced by the multiple layering used during fabrication. SIGNIFICANCE This study provides the insights required to improve prosthesis modelling, to develop new processing routes that minimise residual stress and ultimately to reduce prosthesis failure rates. The PDF approach also offers a powerful new technique for microscale strain quantification in amorphous materials.
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Affiliation(s)
- Alexander J G Lunt
- Department of Engineering Science, University of Oxford, Parks Road, Oxford, OX1 3PJ, United Kingdom.
| | - Philip Chater
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0QX, United Kingdom
| | - Annette Kleppe
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0QX, United Kingdom
| | - Nikolaos Baimpas
- Department of Engineering Science, University of Oxford, Parks Road, Oxford, OX1 3PJ, United Kingdom
| | - Tee K Neo
- Specialist Dental Group, Mount Elizabeth Orchard, #08-03/08-08/08-10, 228510, Singapore
| | - Alexander M Korsunsky
- Department of Engineering Science, University of Oxford, Parks Road, Oxford, OX1 3PJ, United Kingdom
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Ioannidis A, Mühlemann S, Özcan M, Hüsler J, Hämmerle CHF, Benic GI. Ultra-thin occlusal veneers bonded to enamel and made of ceramic or hybrid materials exhibit load-bearing capacities not different from conventional restorations. J Mech Behav Biomed Mater 2018; 90:433-440. [PMID: 30447557 DOI: 10.1016/j.jmbbm.2018.09.041] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [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: 08/02/2018] [Revised: 09/25/2018] [Accepted: 09/25/2018] [Indexed: 11/20/2022]
Abstract
OBJECTIVES The objective of this study was to test whether or not the load-bearing capacity of occlusal veneers bonded to enamel and made of ceramic or hybrid materials does differ from those of porcelain-fused-to-metal or lithium disilicate glass ceramic crowns. MATERIAL AND METHODS In 80 human molars occlusal enamel was removed without extending into the dentin in order to mimic substance defects caused by attrition. The restorations were digitally designed at a standardized thickness of either 0.5 mm or 1.0 mm. For each thickness, 4 test groups were formed each including a different restorative material: "0.5-ZIR": 0.5 mm thick zirconia (Vita YZ HT); "1.0-ZIR": 1.0 mm thick zirconia (Vita YZ HT); "0.5-LDC": 0.5 mm thick lithium disilicate ceramic (IPS e.max Press); "1.0-LDC": 1.0 mm thick lithium disilicate ceramic (IPS e.max Press); "0.5-HYC": 0.5 mm thick PICN (Vita Enamic); "1.0-HYC": 1.0 mm thick PICN (Vita Enamic); "0.5-COC": 0.5 mm thick tooth shaded resin composite (Lava Ultimate) and "1.0-COC": 1.0 mm thick tooth shaded resin composite (Lava ultimate). Each group consists of 10 specimens. Two additional groups of 10 specimens each were used as controls and exhibited conventional crown preparations. In one group the crowns were made of lithium-disilicate ceramic ("CLD": IPS e.max CAD) and the other group consisted of porcelain-fused to metal crowns ("PFM"). All restorations were cemented onto the prepared teeth following the manufacturer's instruction of the corresponding luting cement. Subsequently, they were thermo-mechanically aged and then loaded until fracture. Load-bearing capacities (Fmax) between the groups were compared applying the Kruskal-Wallis test (p < 0.05) and pairwise group comparisons using the Dunn's method. RESULTS Median values (and quartiles) for the load-bearing capacity amounted to (Fmax) 2'407 (1'670; 2'490) N for the CLD group and to 2'033 (1'869; 2'445) N for the PFM group. For the 0.5 mm thick restorations Fmax reached the highest median value in group 0.5-HYC 2'390 (1'355; 2'490) N, followed by 0.5-COC 2'200 (1'217; 2'492) N and 0.5-LDC 1'692 (1'324; 2'355) N. No results were obtained for group 0.5-ZIR due to the impracticability to fabricate ultra-thin specimens. The distribution of the values for the 1.0 mm thick restorations was 2'489 (2'426; 2'491) N for 1.0-COC, 2'299 (2'156; 2'490) N for 1.0-ZIR, 2'124 (1'245; 2'491) N for 1.0-HYC, and 1'537 (1'245; 1'783) N for 1.0-LDC. The differences of the medians between the test and the control groups did not reach statistical significance for the 0.5 mm thick specimens (KW: p = 0.6952 and p = 0.6986). Within the groups exhibiting 1.0 mm thickness, however, significant different medians were found: 1.0-LDC < 1.0-ZIR and 1.0-LDC < 1.0-COC (KW: p < 0.0209). CONCLUSIONS Regarding their maximum load-bearing capacity, minimally invasive occlusal veneers made of ceramic and hybrid materials can be applied to correct occlusal tooth wear and thus replace conventional crown restorations.
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Affiliation(s)
- Alexis Ioannidis
- Clinic of Fixed and Removable Prosthodontics and Dental Material Science, Center of Dental Medicine, University of Zurich, Switzerland.
| | - Sven Mühlemann
- Clinic of Fixed and Removable Prosthodontics and Dental Material Science, Center of Dental Medicine, University of Zurich, Switzerland
| | - Mutlu Özcan
- Clinic of Fixed and Removable Prosthodontics and Dental Material Science, Center of Dental Medicine, University of Zurich, Switzerland
| | - Jürg Hüsler
- Department of Mathematical Statistics, University of Bern, Switzerland
| | - Christoph H F Hämmerle
- Clinic of Fixed and Removable Prosthodontics and Dental Material Science, Center of Dental Medicine, University of Zurich, Switzerland
| | - Goran I Benic
- Clinic of Fixed and Removable Prosthodontics and Dental Material Science, Center of Dental Medicine, University of Zurich, Switzerland
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Moghaddas MJ, Hossainipour Z, Majidinia S, Ojrati N. Comparison of the shear bond strength of self-adhesive resin cements to enamel and dentin with different protocol of application. Electron Physician 2017; 9:4985-4991. [PMID: 28979732 PMCID: PMC5614282 DOI: 10.19082/4985] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 05/17/2017] [Indexed: 11/20/2022] Open
Abstract
AIM The aim of the present study was to determine the shear bond strength of self-adhesive resin cements to enamel and dentin with and without surface treatments, and compare them with conventional resin cement as the control group. METHODS In this experimental study, buccal and lingual surface of the thirty sound human premolars were polished in order to obtain a flat surface of enamel (E) in buccal, and dentin (D) in lingual. Sixty feldspathic ceramic blocks (2×3×3 mm) were prepared and randomly divided into six groups (n=10). Each block was cemented to the prepared surface (30 enamel and 30 dentin surface) according to different protocol: E1 and D1; RelyX ARC as control group, E2, D2; RelyX Unicem, E3, D3; acid etching +RelyX Unicem. The specimens were termocycled and subjected to shear forces by a universal testing machine at a cross head speed of 0.5 mm/min. The mode of fracture were evaluated by stereomicroscope. Data were analyzed with descriptive statistical methods using SPSS version 15. One-way ANOVA, and post hoc Tukey tests were used to compare bond strengths between the groups with different adhesives at α=0.05. RESULTS Statistical analysis showed no significant differences within the enamel subgroups, but there were significant differences within the dentinal subgroups, and statistically significant differences were found between the groups D1and D3 (p=0.02). Comparison between similar enamel and dentinal subgroups showed that there was a significant difference just between the subgroups E3 and D3 (p=0.01). CONCLUSION Elective etching of enamel did not lead to significant increase in the shear bond strength of RelyX Unicem in comparison to RelyX ARC. On the other hand, elective etching of dentin reduces the bond strength of RelyX Unicem with the dentin.
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Affiliation(s)
- Mohammad Javad Moghaddas
- Department of Operative Dentistry, School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Zahra Hossainipour
- School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Sara Majidinia
- Dental Materials Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Najmeh Ojrati
- Postgraduate Student of Operative Dentistry, School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran
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Chougule KJ, Wadkar AP. An In vitro Comparative Evaluation of Flexural Strength of Monolithic Zirconia after Surface Alteration Utilising Two Different Techniques. J Clin Diagn Res 2017; 11:ZC20-ZC23. [PMID: 28969267 DOI: 10.7860/jcdr/2017/25177.10361] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 04/07/2017] [Indexed: 11/24/2022]
Abstract
INTRODUCTION Chairside surface alteration like grinding is often done by clinicians for adjustment of zirconia restorations. To restore the surface of the prostheses, either polishing or glazing is done. However, there is a controversy which of the surface restoration technique helps regain strength of the restoration. AIM This study was conducted to evaluate the effects of chairside surface alteration on flexural strength of Monolithic zirconia. MATERIALS AND METHODS Rectangular zirconia samples (n=30) were prepared by CAD-CAM and divided into three groups. One was control group with no alteration (n=10), second was ground and polished (n=10) and third was ground and reglazed (n=10). Flexural strength testing was performed with a three-point bend test on a universal testing machine. The collected data was statistically analysed for normal distribution using D'Agostino and Pearson omnibus normality test, one-way ANOVA and Tukeys multiple comparison test (p<0.05). RESULTS The mean flexural strength of the reglazed group was significantly higher (648.7 MPa) as compared to the control (507 MPa) or the polished groups (588.5 MPa). CONCLUSION Statistically, reglazing increased the flexural strength as compared to polishing.
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Affiliation(s)
- Ketaki Janardhan Chougule
- Ex-Postgraduate Student, Department of Prosthodontics, Nair Hospital Dental College, Mumbai, Maharashtra, India
| | - Arti Prabodh Wadkar
- Dean and Professor and Head, Department of Prosthodontics, Nair Hospital Dental College, Mumbai, Maharashtra, India
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Gong X, Zhao XY, Zhang CB, Li SB, Wu YL, Wu B. [Effect of sandblasting on bending strength and subcritical crack growth of the dental zirconia ceramics]. Zhonghua Kou Qiang Yi Xue Za Zhi 2017; 52:439-442. [PMID: 29972909 DOI: 10.3760/cma.j.issn.1002-0098.2017.07.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Objective: To evaluate the effect of sandblasting on bending strength and subcritical crack growth (SCG) under cyclic loading of yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) ceramics. Methods: After being polished, sixty bar-shaped specimens of Y-TZP (Wieland zirconia ceramics) were assigned to two groups (n=30) according to the random number table, the sandblasting group (SG) which was treated with sandblasting and the control group (CG) which remained untouched. In each group, half of the specimens (n=15) were subjected to bending strength test, and the results were examined by Weibull statistics and analyzed with ANOVA. The other 15 specimens in each group were subjected to fatigue tests. The results were examined by Weibull statistics and subcritical crack propagation rates were calculated. Results: The bending strengths of SG and CG were (1 291±133) and (1 140±124) MPa (F=10.117, P=0.004), and the Weibull modules of the two groups were 11.06 and 10.64 respectively. The crack growth rate of SCG of SG was lower than that of CG under the same cyclic loading. Conclusions: Proper sandblasting on Y-TZP ceramic can increase its bending strength and resistance to SCG.
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Affiliation(s)
- X Gong
- Department of Dental Materials, School of Stomatology, The Fourth Military Medical University & State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, Xi'an 710032, China
| | - X Y Zhao
- Department of Dental Materials, School of Stomatology, The Fourth Military Medical University & State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, Xi'an 710032, China
| | - C B Zhang
- Department of Laboratory Center, School of Stomatology, The Fourth Military Medical University & State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, Xi'an 710032, China
| | - S B Li
- Department of Dental Materials, School of Stomatology, The Fourth Military Medical University & State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, Xi'an 710032, China
| | - Y L Wu
- Department of Laboratory Center, School of Stomatology, The Fourth Military Medical University & State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, Xi'an 710032, China
| | - B Wu
- Department of Laboratory Center, School of Stomatology, The Fourth Military Medical University & State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, Xi'an 710032, China
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Lunt A, Terry A, Ying S, Baimpas N, Sui T, Kabra S, Kelleher J, King S, Khin NT, Korsunsky AM. Characterisation of nanovoiding in dental porcelain using small angle neutron scattering and transmission electron microscopy. Dent Mater 2017; 33:486-497. [PMID: 28279436 DOI: 10.1016/j.dental.2017.02.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 01/09/2017] [Accepted: 02/16/2017] [Indexed: 10/20/2022]
Abstract
OBJECTIVES Recent studies of the yttria partially stabilised zirconia-porcelain interface have revealed the presence of near-interface porcelain nanovoiding which reduces toughness and leads to component failure. One potential explanation for these nanoscale features is thermal creep which is induced by the combination of the residual stresses at the interface and sintering temperatures applied during manufacture. The present study provides improved understanding of this important phenomenon. METHODS Transmission electron microscopy and small angle neutron scattering were applied to a sample which was crept at 750°C and 100MPa (sample C), a second which was exposed to an identical heat treatment schedule in the absence of applied stress (sample H), and a reference sample in the as-machined state (sample A). RESULTS The complementary insights provided by the two techniques were in good agreement and log-normal void size distributions were found in all samples. The void number density was found to be 1.61μm-2, 25.4μm-2 and 98.6μm-2 in samples A, H and C respectively. The average void diameter in sample A (27.1nm) was found to be more than twice as large as in samples H (10.2nm) and C (11.6nm). The crept data showed the highest skewness parameter (2.35), indicating stress-induced growth of larger voids and void coalescence that has not been previously observed. SIGNIFICANCE The improved insight presented in this study can be integrated into existing models of dental prostheses in order to optimise manufacturing routes and thereby reduce the significant detrimental impact of this nanostructural phenomenon.
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Affiliation(s)
- Alexander Lunt
- Department of Engineering Science, University of Oxford, Parks Road, Oxford, OX1 3PJ, UK.
| | - Ann Terry
- ISIS Pulsed Neutron and Muon Source, Harwell Campus, Didcot, Oxfordshire, OX11 0QX, UK
| | - Siqi Ying
- Department of Engineering Science, University of Oxford, Parks Road, Oxford, OX1 3PJ, UK
| | - Nikolaos Baimpas
- Department of Engineering Science, University of Oxford, Parks Road, Oxford, OX1 3PJ, UK
| | - Tan Sui
- Department of Engineering Science, University of Oxford, Parks Road, Oxford, OX1 3PJ, UK
| | - Saurabh Kabra
- ISIS Pulsed Neutron and Muon Source, Harwell Campus, Didcot, Oxfordshire, OX11 0QX, UK
| | - Joe Kelleher
- ISIS Pulsed Neutron and Muon Source, Harwell Campus, Didcot, Oxfordshire, OX11 0QX, UK
| | - Stephen King
- ISIS Pulsed Neutron and Muon Source, Harwell Campus, Didcot, Oxfordshire, OX11 0QX, UK
| | - Neo Tee Khin
- Specialist Dental Group, Mount Elizabeth Orchard, #08-03/08-08/08-10, 228510, Singapore
| | - Alexander M Korsunsky
- Department of Engineering Science, University of Oxford, Parks Road, Oxford, OX1 3PJ, UK
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Al Moaleem MM, Alkhayrat FM, Madkhali HA, Geathy IH, Qahhar MA, Yaqoub A, Mattoo KA. Subjective Differences between Dentists and Patients about Relative Quality of Metal Ceramic Restorations placed in the Esthetic Zone. J Contemp Dent Pract 2017; 18:112-116. [PMID: 28174363 DOI: 10.5005/jp-journals-10024-2000] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [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: 06/06/2023]
Abstract
INTRODUCTION Esthetic perceptions could differ between the dentist and his patients among various regions and cultures. AIM The aims of this study were to evaluate the subjective differences between the dentist and the patient in terms of esthetics of metal-ceramic crowns (MCcs). The study also aims to compare the mesiodistal (MD) and buccolingual (BL) dimensions of the cemented crown with its respective natural antimeric tooth. MATERIALS AND METHODS A total of 85 patients seeking treatment for a single crown (MC) were treated by the undergraduate students under supervision of respective academic staff. After cementation of the crowns, a 9-point questionnaire was given to patient and different dentists. A treatment cast for every single crown was poured. Then, the MD and BL dimensions of the crowns were compared against their respective antimeric tooth. RESULTS The dentists and the patients agreed in the range of 50.5 to 90.5%. Least subjective differences were found for the length and width of the cemented crowns. The highest differences were noted for symmetry between the cemented crown and its antimeric natural tooth. A total of 31 to 38% of the patients differed from the dentist's evaluation for shade of the crown, color of the crown at the margin, contour of the crown, and the relationship of the crowns with the surrounding gingiva. The highest MD and BL dimensions were in the cemented crown of canines, while the lowest MD and BL diameters were for the cemented crowns of the lateral incisor crowns. CONCLUSION Dentist and patient mostly agreed in terms of length (90%), width (81%) and relation of crown with free gingiva (74%). However, they differed mostly on the symmetry of the cemented crowns. The highest MD dimensions and BL diameter were in the cemented MCcs of canine, while the lowest were with lateral incisors. CLINICAL SIGNIFICANCE While fabricating a dental prosthesis, the dentist must know about patients' perception of esthetics; otherwise both clinical and laboratory efforts would not be enough to satisfy the esthetic needs of the patient even if the restoration is technically correct. Perceptions related to symmetry differ mostly between dentist and patient.
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Affiliation(s)
- Mohammed M Al Moaleem
- Department of Prosthetic, Dental Sciences, College of Dentistry, Jazan University, P.O. Box 114, Jazan, Kingdom of Saudi Arabia, e-mail:
| | - Faisal M Alkhayrat
- Department of Prosthetic, Dental Sciences, College of Dentistry, Jazan University, P.O. Box 114, Jazan, Kingdom of Saudi Arabia
| | - Hussam A Madkhali
- Department of Prosthetic, Dental Sciences, College of Dentistry, Jazan University, P.O. Box 114, Jazan, Kingdom of Saudi Arabia
| | - Ibrahim H Geathy
- Department of Prosthetic, Dental Sciences, College of Dentistry, Jazan University, P.O. Box 114, Jazan, Kingdom of Saudi Arabia
| | - Mohammed Aw Qahhar
- Department of Prosthetic, Dental Sciences, College of Dentistry, Jazan University, P.O. Box 114, Jazan, Kingdom of Saudi Arabia
| | - Ahmed Yaqoub
- Department of Prosthetic, Dental Sciences, College of Dentistry, Jazan University, P.O. Box 114, Jazan, Kingdom of Saudi Arabia
| | - Khurshid A Mattoo
- Department of Prosthetic, Dental Sciences, College of Dentistry, Jazan University, P.O. Box 114, Jazan, Kingdom of Saudi Arabia
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Harabi A, Guerfa F, Harabi E, Benhassine MT, Foughali L, Zaiou S. Preparation and characterization of new dental porcelains, using K-feldspar and quartz raw materials. Effect of B2O3 additions on sintering and mechanical properties. Mater Sci Eng C Mater Biol Appl 2016; 65:33-42. [PMID: 27157725 DOI: 10.1016/j.msec.2016.03.067] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2015] [Revised: 02/20/2016] [Accepted: 03/21/2016] [Indexed: 11/22/2022]
Abstract
The aim of this work was to determine the effect of temperature and boric oxide (B2O3) addition on sintering and mechanical properties of a newly developed dental porcelain (DP) prepared from local Algerian raw materials. Based on a preliminary work, the new selected composition was 75wt.% feldspar, 20wt.% quartz and 5wt.% kaolin. It was prepared by sintering the mixture at different temperatures (1100-1250°C). The optimum sintering conditions gave a relatively higher density (2.47g/cm(3)) and excellent mechanical properties. The three point flexural strength (3PFS) and Martens micro-hardness of dental porcelains were 149MPa and 2600MPa, respectively. This obtained 3PFS value is more than four times greater than that of hydroxyapatite (HA) value (about 37MPa) sintered under the same conditions. However, the sintering temperature was lowered by about 25 and 50°C for 3 and 5wt.% B2O3 additions, respectively. But, it did not improve furthermore the samples density and their mechanical properties. It has also been found that B2O3 additions provoke a glass matrix composition variation which delays the leucite formation during sintering.
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Huettig F, Gehrke UP. Early complications and performance of 327 heat-pressed lithium disilicate crowns up to five years. J Adv Prosthodont 2016; 8:194-200. [PMID: 27350853 PMCID: PMC4919489 DOI: 10.4047/jap.2016.8.3.194] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2015] [Revised: 02/03/2016] [Accepted: 04/26/2016] [Indexed: 11/08/2022] Open
Abstract
PURPOSE The prospective follow-up aimed to assess the performance of lithium disilicate crowns and clinical reasons of adverse events compromising survival and quality. MATERIALS AND METHODS 58 patients were treated with 375 heat-pressed monolithic crowns, which were bonded with resin cement. Annual recalls up to five years included a complete dental examination as well as quality assessment using CDA-criteria. Any need for clinical intervention led to higher complication rate and any failure compromised the survival rate. Kaplan-Meier-method was applied to all crowns and a dataset containing one randomly selected crown from each patient. RESULTS Due to drop-outs, 45 patients (31 females, 14 males) with the average age of 43 years (range = 17-73) who had 327 crowns (176 anterior, 151 posterior; 203 upper jaw, 124 lower jaw) were observed and evaluated for between 4 and 51 months (median = 28). Observation revealed 4 chippings, 3 losses of retention, 3 fractures, 3 secondary caries, 1 endodontic problem, and 1 tooth fracture. Four crowns had to be removed. Survival and complication rate was estimated 98.2% and 5.4% at 24 months, and 96.8% and 7.1% at 48 months. The complication rate was significantly higher for root canal treated teeth (12%, P<.01) at 24 months. At the last observation, over 90% of all crowns showed excellent ratings (CDA-rating Alfa) for color, marginal fit, and caries. CONCLUSION Heat pressed lithium disilicate crowns showed an excellent performance. Besides a careful luting, dentists should be aware of patients' biological prerequisites (grade of caries, oral hygiene) to reach full success with these crowns.
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Affiliation(s)
- Fabian Huettig
- Department of Prosthodontics, Centre for Dentistry, Oral Medicine, and Maxillofacial Surgery, Eberhard-Karls-Universität Tübingen, Tübingen, Germany
| | - Ulf Peter Gehrke
- Department of Prosthodontics, Centre for Dentistry, Oral Medicine, and Maxillofacial Surgery, Eberhard-Karls-Universität Tübingen, Tübingen, Germany
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Ramos NDC, Campos TMB, Paz ISDL, Machado JPB, Bottino MA, Cesar PF, Melo RMD. Microstructure characterization and SCG of newly engineered dental ceramics. Dent Mater 2016; 32:870-8. [PMID: 27094589 DOI: 10.1016/j.dental.2016.03.018] [Citation(s) in RCA: 117] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Revised: 11/23/2015] [Accepted: 03/22/2016] [Indexed: 11/26/2022]
Abstract
OBJECTIVES The aim of this study was to characterize the microstructure of four dental CAD-CAM ceramics and evaluate their susceptibility to stress corrosion. METHODS SEM and EDS were performed for microstructural characterization. For evaluation of the pattern of crystallization of the ceramics and the molecular composition, XRD and FTIR, respectively, were used. Elastic modulus, Poisson's ratio, density and fracture toughness were also measured. The specimens were subjected to biaxial flexure under five stress rates (0.006, 0.06, 0.6, 6 and 60MPa/s) to determine the subcritical crack growth parameters (n and D). Twenty-five specimens were further tested in mineral oil for determination of Weibull parameters. Two hundred forty ceramic discs (12mm diameter and 1.2mm thick) were made from four ceramics: feldspathic ceramic - FEL (Vita Mark II, Vita Zahnfabrik), ceramic-infiltrated polymer - PIC (Vita Enamic, Vita Zahnfabrik), lithium disilicate - LD (IPS e.max CAD, Ivoclar Vivadent) and zirconia-reinforced lithium silicate - LS (Vita Suprinity, Vita Zahnfabrik). RESULTS PIC discs presented organic and inorganic phases (n=29.1±7.7) and Weibull modulus (m) of 8.96. The FEL discs showed n=36.6±6.8 and m=8.02. The LD discs showed a structure with needle-like disilicate grains in a glassy matrix and had the lowest value of n (8.4±0.8) and m=6.19. The ZLS discs showed similar rod-like grains, n=11.2±1.4 and m=9.98. SIGNIFICANCE The FEL and PIC discs showed the lowest susceptibility to slow crack growth (SCG), whereas the LD and ZLS discs presented the highest. PIC presented the lowest elastic modulus and no crystals in its composition, while ZLS presented tetragonal zirconia. The overall strength and SCG of the new materials did not benefit from the additional phase or microconstituents present in them.
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Affiliation(s)
- Nathália de Carvalho Ramos
- Department of Dental Materials and Prosthodontics, São Paulo State University (UNESP), Institute of Science and Technology, 777 Eng. Francisco José Longo Avenue, 12245-000, São José dos Campos, SP, Brazil
| | - Tiago Moreira Bastos Campos
- Aeronautics Technological Institute (ITA), 50 Praça Marechal Eduardo Gomes, 12228-900, São José dos Campos, SP, Brazil
| | - Igor Siqueira de La Paz
- Department of Dental Materials and Prosthodontics, São Paulo State University (UNESP), Institute of Science and Technology, 777 Eng. Francisco José Longo Avenue, 12245-000, São José dos Campos, SP, Brazil
| | - João Paulo Barros Machado
- National Institute for Space Research, Associated Laboratory of Sensors and Materials, 1758 Astronautas Avenue, 12217-010, São José dos Campos, SP, Brazil
| | - Marco Antonio Bottino
- Department of Dental Materials and Prosthodontics, São Paulo State University (UNESP), Institute of Science and Technology, 777 Eng. Francisco José Longo Avenue, 12245-000, São José dos Campos, SP, Brazil
| | - Paulo Francisco Cesar
- University of São Paulo (USP), School of Dentistry, Department of Biomaterials and Oral Biology, 2227 Prof. Lineu Prestes Avenue, 05508-000, São Paulo, SP, Brazil
| | - Renata Marques de Melo
- Department of Dental Materials and Prosthodontics, São Paulo State University (UNESP), Institute of Science and Technology, 777 Eng. Francisco José Longo Avenue, 12245-000, São José dos Campos, SP, Brazil.
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Minesaki Y, Murahara S, Kajihara Y, Takenouchi Y, Tanaka T, Suzuki S, Minami H. Effect of metal conditioner on bonding of porcelain to cobalt-chromium alloy. J Adv Prosthodont 2016; 8:1-8. [PMID: 26949481 PMCID: PMC4769884 DOI: 10.4047/jap.2016.8.1.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Revised: 11/26/2015] [Accepted: 12/14/2015] [Indexed: 11/22/2022] Open
Abstract
PURPOSE The purpose of this study was to evaluate the efficacy of two different metal conditioners for non-precious metal alloys for the bonding of porcelain to a cobalt-chromium (Co-Cr) alloy. MATERIALS AND METHODS Disk-shaped specimens (2.5×10.0 mm) were cast with Co-Cr alloy and used as adherend materials. The bonding surfaces were polished with a 600-grid silicon carbide paper and airborne-particle abraded using 110 µm alumina particles. Bonding specimens were fabricated by applying and firing either of the metal conditioners on the airborne-particle abraded surface, followed by firing porcelain into 5 mm in diameter and 3 mm in height. Specimens without metal conditioner were also fabricated. Shear bond strength for each group (n=8) were measured and compared (α=.05). Sectional view of bonding interface was observed by SEM. EDS analysis was performed to determine the chemical elements of metal conditioners and to determine the failure modes after shear test. RESULTS There were significant differences among three groups, and two metal conditioner-applied groups showed significantly higher values compared to the non-metal conditioner group. The SEM observation of the sectional view at bonding interface revealed loose contact at porcelain-alloy surface for non-metal conditioner group, however, close contact at both alloy-metal conditioner and metal conditioner-porcelain interfaces for both metal conditioner-applied groups. All the specimens showed mixed failures. EDS analysis showed that one metal conditioner was Si-based material, and another was Ti-based material. Si-based metal conditioner showed higher bond strengths compared to the Ti-based metal conditioner, but exhibited more porous failure surface failure. CONCLUSION Based on the results of this study, it can be stated that the application of metal conditioner is recommended for the bonding of porcelain to cobalt-chromium alloys.
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Affiliation(s)
- Yoshito Minesaki
- Kagoshima University Medical and Dental Hospital, Fixed Prosthetic Clinic, Kagoshima, Japan
| | - Sadaaki Murahara
- Kagoshima University Graduate School of Medical and Dental Sciences, Department of Fixed Prosthodontics, Kagoshima, Japan
| | - Yutaro Kajihara
- Kagoshima University Medical and Dental Hospital, Fixed Prosthetic Clinic, Kagoshima, Japan
| | | | - Takuo Tanaka
- Kagoshima University Graduate School of Medical and Dental Sciences, Department of Fixed Prosthodontics, Kagoshima, Japan
| | - Shiro Suzuki
- School of Dentistry, University of Alabama at Birmingham, Division of Biomaterials, Birmingham, Alabama, United States of America
| | - Hiroyuki Minami
- Kagoshima University Graduate School of Medical and Dental Sciences, Department of Fixed Prosthodontics, Kagoshima, Japan
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Zanardi PR, Laia Rocha Zanardi R, Chaib Stegun R, Sesma N, Costa BN, Cruz Laganá D. The Use of the Digital Smile Design Concept as an Auxiliary Tool in Aesthetic Rehabilitation: A Case Report. Open Dent J 2016; 10:28-34. [PMID: 27006721 PMCID: PMC4780488 DOI: 10.2174/1874210601610010028] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Revised: 10/28/2015] [Accepted: 11/15/2015] [Indexed: 11/22/2022] Open
Abstract
The digital smile design is a practical diagnosis method that can assist the clinician to visualize and measure dentogingival discrepancies. This clinical report aims to present the associated steps, from the diagnosis of the alterations diagnosis through to the final aesthetic result. A 37-years-old female patient presented as her main complaint the tooth form and colour discrepancies. Applying the digital smile design principle, the necessary measures for a harmonic smile correction could be accurately determined. The initial diagnosis led to a wax up of the master cast that was duplicated in acrylic resin directly in the mouth. This temporary restoration guided the periodontal surgery and the final pressed ceramic crown restoration. We conclude that the digital smile design concept seems to be a useful tool to achieve a satisfactory aesthetic result.
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Affiliation(s)
- Piero Rocha Zanardi
- Department of Prosthodontics, School of Dentistry, University of São Paulo, São Paulo, Brazil
| | | | - Roberto Chaib Stegun
- Department of Prosthodontics, School of Dentistry, University of São Paulo, São Paulo, Brazil
| | - Newton Sesma
- Department of Prosthodontics, School of Dentistry, University of São Paulo, São Paulo, Brazil
| | - Bru-No Costa
- Department of Prosthodontics, School of Dentistry, University of São Paulo, São Paulo, Brazil
| | - Dalva Cruz Laganá
- Department of Prosthodontics, School of Dentistry, University of São Paulo, São Paulo, Brazil
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Turk AG, Ulusoy M, Yuce M, Akin H. Effect of different veneering techniques on the fracture strength of metal and zirconia frameworks. J Adv Prosthodont 2016; 7:454-9. [PMID: 26816575 PMCID: PMC4722149 DOI: 10.4047/jap.2015.7.6.454] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Revised: 09/02/2015] [Accepted: 10/20/2015] [Indexed: 11/08/2022] Open
Abstract
PURPOSE To determine whether the fracture strengths and failure types differed between metal and zirconia frameworks veneered with pressable or layering ceramics. MATERIALS AND METHODS A phantom molar tooth was prepared and duplicated in 40 cobalt-chromium abutments. Twenty metal (IPS d.SIGN 15, Ivoclar, Vivadent, Schaan, Liechtenstein) and 20 zirconia (IPS e.max ZirCAD, Ivoclar) frameworks were fabricated on the abutments. Each framework group was randomly divided into 2 subgroups according to the veneering material: pressable and layering ceramics (n=10). Forty molar crowns were fabricated, cemented onto the corresponding abutments and then thermocycled (5-55℃, 10,000 cycles). A load was applied in a universal testing machine until a fracture occurred on the crowns. In addition, failure types were examined using a stereomicroscope. Fracture load data were analyzed using one-way ANOVA and Tukey HSD post-hoc tests at a significance level of 0.05. RESULTS The highest strength value was seen in metal-pressable (MP) group, whereas zirconia-pressable (ZP) group exhibited the lowest one. Moreover, group MP showed significantly higher fracture loads than group ZP (P=.015) and zirconia-layering (ZL) (P=.038) group. No significant difference in fracture strength was detected between groups MP and ML, and groups ZP and ZL (P>.05). Predominant fracture types were cohesive for metal groups and adhesive for zirconia groups. CONCLUSION Fracture strength of a restoration with a metal or a zirconia framework was independent of the veneering techniques. However, the pressing technique over metal frameworks resisted significantly higher fracture loads than zirconia frameworks.
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Affiliation(s)
- Ayse Gozde Turk
- Department of Prosthodontics, Faculty of Dentistry, University of Ege, Izmir, Turkey
| | - Mubin Ulusoy
- Department of Prosthodontics, Faculty of Dentistry, University of Ege, Izmir, Turkey
| | | | - Hakan Akin
- Department of Prosthodontics, Faculty of Dentistry, Cumhuriyet University, Sivas, Turkey
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Oh JW, Song KY, Ahn SG, Park JM, Lee MH, Seo JM. Effects of core characters and veneering technique on biaxial flexural strength in porcelain fused to metal and porcelain veneered zirconia. J Adv Prosthodont 2015; 7:349-57. [PMID: 26576250 PMCID: PMC4644775 DOI: 10.4047/jap.2015.7.5.349] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 01/02/2015] [Accepted: 01/09/2015] [Indexed: 11/08/2022] Open
Abstract
PURPOSE The purpose of this study was to assess the impact of the core materials, thickness and fabrication methods of veneering porcelain on prosthesis fracture in the porcelain fused to metal and the porcelain veneered zirconia. MATERIALS AND METHODS Forty nickel-chrome alloy cores and 40 zirconia cores were made. Half of each core group was 0.5 mm-in thickness and the other half was 1.0 mm-in thickness. Thus, there were four groups with 20 cores/group. Each group was divided into two subgroups with two different veneering methods (conventional powder/liquid layering technique and the heat-pressing technique). Tensile strength was measured using the biaxial flexural strength test based on the ISO standard 6872:2008 and Weibull analysis was conducted. Factors influencing fracture strength were analyzed through three-way ANOVA (α≤.05) and the influence of core thickness and veneering method in each core materials was assessed using two-way ANOVA (α≤.05). RESULTS The biaxial flexural strength test showed that the fabrication method of veneering porcelain has the largest impact on the fracture strength followed by the core thickness and the core material. In the metal groups, both the core thickness and the fabrication method of the veneering porcelain significantly influenced on the fracture strength, while only the fabrication method affected the fracture strength in the zirconia groups. CONCLUSION The fabrication method is more influential to the strength of a prosthesis compared to the core character determined by material and thickness of the core.
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Affiliation(s)
- Ju-Won Oh
- Department of Prosthodontics, School of Dentistry and Institute of Oral Bio-Science, Chonbuk National University, Jeonju, Republic of Korea
| | - Kwang-Yeob Song
- Department of Prosthodontics, School of Dentistry and Institute of Oral Bio-Science, Chonbuk National University, Jeonju, Republic of Korea. ; Biomedical Research Institute, Chonbuk National University Hospital, Jeonju, Republic of Korea
| | - Seung-Geun Ahn
- Department of Prosthodontics, School of Dentistry and Institute of Oral Bio-Science, Chonbuk National University, Jeonju, Republic of Korea. ; Biomedical Research Institute, Chonbuk National University Hospital, Jeonju, Republic of Korea
| | - Ju-Mi Park
- Department of Prosthodontics, School of Dentistry and Institute of Oral Bio-Science, Chonbuk National University, Jeonju, Republic of Korea. ; Biomedical Research Institute, Chonbuk National University Hospital, Jeonju, Republic of Korea
| | - Min-Ho Lee
- Department Dental Biomaterials, Institute of Oral Bio-science, School of Dentistry, Chonbuk National University, Jeonju, Republic of Korea
| | - Jae-Min Seo
- Department of Prosthodontics, School of Dentistry and Institute of Oral Bio-Science, Chonbuk National University, Jeonju, Republic of Korea. ; Biomedical Research Institute, Chonbuk National University Hospital, Jeonju, Republic of Korea
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Lee WS, Kim SY, Kim JH, Kim WC, Kim HY. The effect of powder A2/powder A3 mixing ratio on color and translucency parameters of dental porcelain. J Adv Prosthodont 2015; 7:400-5. [PMID: 26576257 PMCID: PMC4644782 DOI: 10.4047/jap.2015.7.5.400] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 09/18/2015] [Accepted: 09/23/2015] [Indexed: 11/08/2022] Open
Abstract
PURPOSE The purpose of this study is to mix dental ceramic powder in varying ratios and evaluate the effect of the mixing ratio on color and translucency. MATERIALS AND METHODS The ceramic powder of shade A3 of the same product was mixed with the shade A2 of three products: IPS e.max Ceram (Ivoclar Vivadent, Schaan, Liechtenstein), Vintage Halo (SHOFU Inc., Kyoto, Japan), and Ceramco 3 (Ceramco-Dentsply, Burlington, NJ, USA) in the following fixed ratios (0 wt%, 25 wt%, 50 wt%, 75 wt%, and 100 wt%) and then fired. A total of 150 specimen of ceramic fired were manufactured in a regular size (W: 8.5 mm, L: 10.5 mm, and H: 1.5 mm). For color and translucency, L*, a*, and b* were measured and Two-way analysis of variance (ANOVA) and One-way analysis of variance (ANOVA) were used for data analysis (α=0.05). RESULTS The higher the mixing ratio was, L*, a*, and b* of IPS e.max Ceram were all increased, and L* of Vintage Halo was reduced and a* and b* were increased. L* and a* of Ceramco3 were reduced and b* of Ceramco3 was increased. Color difference (ΔE*ab) was increased in all three products as the mixing ratio got higher. Increased mixing ratios resulted in decreased translucency parameter (TP) values for IPS e.max Ceram but increased TP values for Vintage Halo and Ceramco3. CONCLUSION In this limited study, CIE L*, a*, and b* were influenced by the mixing ratio of the A3 powders and porcelain powder mixtures represented a various color and translucency.
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Affiliation(s)
- Wan-Sun Lee
- Dental Laboratory Science and Engineering, Korea University, Seoul, Republic of Korea
| | - So-Yeon Kim
- Dental Laboratory Science and Engineering, Korea University, Seoul, Republic of Korea
| | - Ji-Hwan Kim
- Dental Laboratory Science and Engineering, Korea University, Seoul, Republic of Korea
| | - Woong-Chul Kim
- Dental Laboratory Science and Engineering, Korea University, Seoul, Republic of Korea
| | - Hae-Young Kim
- Dental Laboratory Science and Engineering, Korea University, Seoul, Republic of Korea
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Kajima Y, Takaichi A, Yasue T, Doi H, Takahashi H, Hanawa T, Wakabayashi N. Evaluation of the shear bond strength of dental porcelain and the low magnetic susceptibility Zr-14Nb alloy. J Mech Behav Biomed Mater 2015; 53:131-141. [PMID: 26318573 DOI: 10.1016/j.jmbbm.2015.08.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 08/01/2015] [Accepted: 08/04/2015] [Indexed: 11/16/2022]
Abstract
The aim of this study was to investigate the bond strength of dental porcelain and the preheated Zr-14Nb alloy, and compare this strength with that of titanium. White oxide layers, which were predominantly composed of monoclinic zirconia, were formed on the preheated sample groups, and exhibited a greater roughness than the control samples. At the metal-ceramic interface, a greater Nb diffusion range was observed than in the control samples. The bond strengths of the samples subjected to 20min preheating treatment were the lowest (33.6 ± 3.2 MPa), which may be ascribed to the formation of a brittle thick oxide layer under excessive heat treatment. The samples subjected to this heat treatment for 5 min exhibited the highest mean bond strength (43.7 ± 5.9 MPa), which was significantly higher than that of titanium (35.3 ± 3.5 MPa). Thus, the Zr-14Nb alloy is a promising candidate for fixed dental prosthesis, as long as the appropriate treatment conditions are adopted.
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Affiliation(s)
- Yuka Kajima
- Removable Partial Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan
| | - Atsushi Takaichi
- Removable Partial Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan.
| | - Tohru Yasue
- Fixed Prosthetic Engineering, School of Oral Health Care Sciences, Faculty of Dentistry, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan
| | - Hisashi Doi
- Metallic Biomaterials, Biomedical Materials, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Kanda-surugadai, Chiyoda-ku, Tokyo 101-0062, Japan
| | - Hidekazu Takahashi
- Oral Biomaterials Engineering, Course of Oral Health Engineering, School of Oral Health Care Sciences, Faculty of Dentistry, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan
| | - Takao Hanawa
- Metallic Biomaterials, Biomedical Materials, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Kanda-surugadai, Chiyoda-ku, Tokyo 101-0062, Japan
| | - Noriyuki Wakabayashi
- Removable Partial Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan
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Sendão IA, Alves AC, Galo R, Toptan F, Silva FS, Ariza E. The effect of thermal cycling on the shear bond strength of porcelain/Ti-6Al-4V interfaces. J Mech Behav Biomed Mater 2015; 44:156-63. [PMID: 25643618 DOI: 10.1016/j.jmbbm.2015.01.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 12/23/2014] [Accepted: 01/03/2015] [Indexed: 11/22/2022]
Abstract
The aim of the study was to evaluate the effect of thermal cycling on the shear bond strength of the porcelain/Ti-6Al-4V interfaces prepared by two different processing routes and metallic surface conditions. Polished and SiO2 particle abraded Ti-6Al-4V alloy and Triceram bonder porcelain were used to produce the interfaces. Porcelain-to-metal specimens were processed by conventional furnace firing and hot pressing. Thermal cycling was performed in Fusayama's artificial saliva for 5000 cycles between 5 ± 1 and 60 ± 2°C. After thermal cycling, shear bond tests were carried out by using a custom-made stainless steel apparatus. The results were analyzed using t-Student test and non-parametric Kruskal-Wallis test (p<0.01). Most of the polished-fired specimens were fractured during thermal cycling; thus, it was not possible to obtain the shear bond strength results for this group. Sandblasted-fired, polished-hot pressed, and sandblasted-hot pressed specimens presented the shear bond strength values of 76.2 ± 15.9, 52.2 ± 23.6, and 59.9 ± 22.0 MPa, respectively. Statistical analysis indicated that thermal cycling affected the polished specimens processed by firing, whereas a significant difference was not observed on the other groups.
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Valian A, Moravej-Salehi E. Surface treatment of feldspathic porcelain: scanning electron microscopy analysis. J Adv Prosthodont 2014; 6:387-94. [PMID: 25352961 PMCID: PMC4211055 DOI: 10.4047/jap.2014.6.5.387] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 07/07/2014] [Accepted: 07/08/2014] [Indexed: 11/08/2022] Open
Abstract
PURPOSE Topographic analysis of treated ceramics provides qualitative information regarding the surface texture affecting the micromechanical retention and locking of resin-ceramics. This study aims to compare the surface microstructure following different surface treatments of feldspathic porcelain. MATERIALS AND METHODS This in-vitro study was conducted on 72 porcelain discs randomly divided into 12 groups (n=6). In 9 groups, feldspathic surfaces were subjected to sandblasting at 2, 3 or 4 bar pressure for 5, 10 or 15 seconds with 50 µm alumina particles at a 5 mm distance. In group 10, 9.5% hydrofluoric acid (HF) gel was applied for 120 seconds. In group 11, specimens were sandblasted at 3 bar pressure for 10 seconds and then conditioned with HF. In group 12, specimens were first treated with HF and then sandblasted at 3 bar pressure for 10 seconds. All specimens were then evaluated under scanning electron microscopy (SEM) at different magnifications. RESULTS SEM images of HF treated specimens revealed deep porosities of variable sizes; whereas, the sandblasted surfaces were more homogenous and had sharper peaks. Increasing the pressure and duration of sandblasting increased the surface roughness. SEM images of the two combined techniques showed that in group 11 (sandblasted first), HF caused deeper porosities; whereas in group 12 (treated with HF first) sandblasting caused irregularities with less homogeneity. CONCLUSION All surface treatments increased the surface area and caused porous surfaces. In groups subjected to HF, the porosities were deeper than those in sandblasted only groups.
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Affiliation(s)
- Azam Valian
- Department of Restorative Dentistry, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Elham Moravej-Salehi
- Department of Restorative Dentistry, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Diniz AC, Nascimento RM, Souza JCM, Henriques BB, Carreiro AFP. Fracture and shear bond strength analyses of different dental veneering ceramics to zirconia. Mater Sci Eng C Mater Biol Appl 2014; 38:79-84. [PMID: 24656355 DOI: 10.1016/j.msec.2014.01.032] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 11/25/2013] [Accepted: 01/18/2014] [Indexed: 10/25/2022]
Abstract
The purpose of this work was to evaluate the interaction of different layering porcelains with zirconia via shear bond strength test and microscopy. Four different groups of dental veneering porcelains (VM9, Zirkonzanh, Ceramco, IPS) were fused onto forty zirconia-based cylindrical substrates (8mm in diameter and 12 mm in height) (n=10), according to the manufacturer's recommendations. Additionally, layered dental porcelain (D-sign, Ivoclar) was fired on ten Ni-Cr cylindrical substrates Shear bond strength tests of the veneering porcelain to zirconia or Ni-Cr were carried out at a crosshead speed of 0.5mm/min. After the shear bond tests, the interfaces were analyzed by scanning electron microscopy (SEM). The fracture type exhibited by the different systems was also assessed. The results were statistically analyzed by ANOVA at a significant level of p<.05. The shear bond strength values of the porcelain-to-NiCr interfaces (25.3±7.1 MPa) were significantly higher than those recorded for the following porcelain-to-zirconia systems: Zirkonzanh (18.8±1 MPa), Ceramco (18.2±4.7 MPa), and IPS (16±4.5 MPa). However, no significant differences were found in the shear bond strength values between the porcelain-to-NiCr and porcelain (VM9)-to-zirconia (23.2±5.1 MPa) groups (p>.05). All-ceramic interfaces revealed mixed failure type, cohesive in the porcelain and adhesive at the interface. This study demonstrated that all-ceramic systems do not attain yet the same bond strength standards equivalent to metal-ceramic systems. Therefore, despite the esthetic appeal of all-ceramic restorations, the adhesion between the porcelain and zirconia framework is still an issue considering the long term success of the restoration.
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Affiliation(s)
- Alexandre C Diniz
- School of Dentistry (DOD), Division of Prosthodontics, Universidade Federal do Rio Grande do Norte -UFRN, 59056-000, Natal, Brazil
| | - Rubens M Nascimento
- Materials Engineering Department, Universidade Federal do Rio Grande do Norte - UFRN, Natal, Brazil
| | - Julio C M Souza
- Centre for Mechanics and Materials Technologies - CT2M, Department of Mechanical Engineering (DEM), Universidade do Minho, Campus Azurém, 4800-058, Guimarães, Portugal
| | - Bruno B Henriques
- Materials Engineering Department, Universidade Federal do Rio Grande do Norte - UFRN, Natal, Brazil; Centre for Mechanics and Materials Technologies - CT2M, Department of Mechanical Engineering (DEM), Universidade do Minho, Campus Azurém, 4800-058, Guimarães, Portugal
| | - Adriana F P Carreiro
- School of Dentistry (DOD), Division of Prosthodontics, Universidade Federal do Rio Grande do Norte -UFRN, 59056-000, Natal, Brazil.
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Bachhav VC, Aras MA. The effect of ceramic thickness and number of firings on the color of a zirconium oxide based all ceramic system fabricated using CAD/CAM technology. J Adv Prosthodont 2011; 3:57-62. [PMID: 21814612 PMCID: PMC3141119 DOI: 10.4047/jap.2011.3.2.57] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Revised: 04/30/2011] [Accepted: 05/09/2011] [Indexed: 11/23/2022] Open
Abstract
PURPOSE Ceramics have a long history in fixed prosthodontics for achieving optimal esthetics and various materials have been used to improve ceramic core strength. However, there is a lack of information on how color is affected by fabrication procedure. The purpose of this study was to evaluate the effects of various dentin ceramic thicknesses and repeated firings on the color of zirconium oxide all-ceramic system (Lava™) fabricated using CAD/CAM technology. MATERIALS AND METHODS Thirty disc-shaped cores, 12 mm in diameter with a 1 mm thickness were fabricated from zirconium oxide based all ceramic systems (Lava™, 3M ESPE, St Paul, MN, USA) and divided into three groups (n = 10) according to veneering with dentin ceramic thicknesses: as 0.5, 1, or 1.5 mm. Repeated firings (3, 5, 7, or 9) were performed, and the color of the specimens was compared with the color after the initial firing. Color differences among ceramic specimens were measured using a spectrophotometer (VITA Easyshade, VITA Zahnfabrik, Bad Säckingen, Germany) and data were expressed in CIELAB system coordinates. A repeated measures ANOVA and Bonferroni post hoc test were used to analyze the data (n = 10, α=.05). RESULTS L*a*b* values of the ceramic systems were affected by the number of firings (3, 5, 7, or 9 firings) (P<.001) and ceramic thickness (0.5, 1, or 1.5 mm) (P<.001). Significant interactions were present in L*a*b* values between the number of firings and ceramic thickness (P<.001). An increase in number of firings resulted in significant increase in L* values for both 0.5 mm and 1.5 mm thicknesses (P<.01, P=.013); however it decreased for 1 mm thickness (P<.01). The a* values increased for 1 mm and 1.5 mm thicknesses (P<.01), while it decreased for 0.5 mm specimens. The b* values increased significantly for all thicknesses (P<.01, P=.022). As the dentin ceramic thickness increased, significant reductions in L* values (P<.01) were recorded. There were significant increases in both a* and b* values (P<.01) as the dentin ceramic thickness increased. CONCLUSION The number of firings and dentin ceramic thickness have a definite effect on the final color of all ceramic system tested. The mean ΔE value increased as the dentin ceramic thicknesses increased for zirconium-oxide based all ceramic specimens tested. However, the mean ΔE values were less than 3.7ΔE units which is rated as a match in the oral environment.
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Affiliation(s)
- Vinay Chila Bachhav
- Department of Prosthodontics, Goa Dental College and Hospital, Bambolim, Goa, India
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Kukiattrakoon B, Hengtrakool C, Kedjarune-Leggat U. Effect of acidic agents on surface roughness of dental ceramics. Dent Res J (Isfahan) 2011; 8:6-15. [PMID: 22132009 PMCID: PMC3177383] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND An increase in surface roughness of ceramics may decrease strength and affect the clinical success of ceramic restorations. However, little is known about the effect of acidic agents on ceramic restorations. The aim of this study was to evaluate the surface roughness of dental ceramics after being immersed in acidic agents. METHODS Eighty-three ceramic disk specimens (12.0 mm in diameter and 2.0 mm in thickness) were made from four types of ceramics (VMK 95, Vitadur Alpha, IPS Empress Esthetic, and IPS e.max Ceram). Baseline data of surface roughness were recorded by profilometer. The specimens were then immersed in acidic agents (citrate buffer solution, pineapple juice and green mango juice) and deionized water (control) at 37°C for 168 hours. One group was immersed in 4% acetic acid at 80°C for 168 hours. After immersion, surface roughness was evaluated by a profilometer at intervals of 24, 96, and 168 hours. Surface characteristics of specimens were studied using scanning electron microscopy (SEM). Data were analyzed using two-way repeated ANOVA and Tukey's multiple comparisons (α = 0.05). RESULTS For all studied ceramics, all surface roughness parameters were significantly increased after 168 hours immersion in all acidic agents (P < 0.05). After 168 hours in 4% acetic acid, there were significant differences for all roughness parameters from other acidic agents of all evaluated ceramics. Among all studied ceramics, Vitadur Alpha showed significantly the greatest values of all surface roughness parameters after immersion in 4% acetic acid (P < 0.001). SEM photomicrographs also presented surface destruction of ceramics in varying degrees. CONCLUSION Acidic agents used in this study negatively affected the surface of ceramic materials. This should be considered when restoring the eroded tooth with ceramic restorations in patients who have a high risk of erosive conditions.
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Affiliation(s)
- Boonlert Kukiattrakoon
- Associate Professor, Department of Conservative Dentistry, School of Dentistry, Prince of Songkla University, Hat Yai, Songkhla, Thailand.,
Correspondence to: Boonlert Kukiattrakoon,
| | - Chanothai Hengtrakool
- Assistant Professor, Department of Conservative Dentistry, School of Dentistry, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| | - Ureporn Kedjarune-Leggat
- Associate Professor, Department of Oral Biology and Occlusion, School of Dentistry, Prince of Songkla University, Hat Yai, Songkhla, Thailand
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