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Mayinger F, Ender A, Strickstrock M, Elsayed A, Nassary Zadeh P, Zimmermann M, Stawarczyk B. Impact of the sintering parameters on the grain size, crystal phases, translucency, biaxial flexural strength, and fracture load of zirconia materials. J Mech Behav Biomed Mater 2024; 155:106580. [PMID: 38759588 DOI: 10.1016/j.jmbbm.2024.106580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Revised: 05/06/2024] [Accepted: 05/10/2024] [Indexed: 05/19/2024]
Abstract
OBJECTIVES To investigate the influence of the zirconia and sintering parameters on the optical and mechanical properties. METHODS Three zirconia materials (3/4Y-TZP, 4Y-TZP, 3Y-TZP) were high-speed (HSS), speed (SS) or conventionally (CS) sintered. Disc-shaped specimens nested in 4 vertical layers of the blank were examined for grain size (GS), crystal phases (c/t'/t/m-phase), translucency (T), and biaxial flexural strength. Fracture load (FL) of three-unit fixed dental prostheses was determined initially and after thermomechanical aging. Fracture types were classified, and data statistically analyzed. RESULTS 4Y-TZP showed a higher amount of c + t'-phase and lower amount of t-phase, and higher optical and lower mechanical properties than 3Y-TZP. In all materials, T declined from Layer 1 to 4. 3/4Y-TZP showed the highest FL, followed by 3Y-TZP, while 4Y-TZP showed the lowest. In 4Y-TZP, the sintering parameters exercised a direct impact on GS and T, while mechanical properties were largely unaffected. The sintering parameters showed a varying influence on 3Y-TZP. Thermomechanical aging resulted in comparable or higher FL. CONCLUSION 3/4Y-TZP presenting the highest FL underscores the principle of using strength-gradient multi-layer blanks to profit from high optical properties in the incisal area, while ensuring high mechanical properties in the lower areas subject to tensile forces. With all groups exceeding maximum bite forces, the examined three-unit FDPs showed promising long-term mechanical properties.
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Affiliation(s)
- Felicitas Mayinger
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestraße 70, 80336, Munich, Germany.
| | - Andreas Ender
- Division of Computerized Restorative Dentistry, Clinic of Conservative and Preventive Dentistry, Center of Dental Medicine, University of Zurich, Plattenstrasse 11, 8032, Zurich, Switzerland
| | - Monika Strickstrock
- Faculty of Engineering and Computer Science, Material Science and Analysis, University of Applied Sciences Osnabrück, Albrechtstraße 30, 49076, Osnabrück, Germany
| | - Adham Elsayed
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestraße 70, 80336, Munich, Germany
| | - Parissa Nassary Zadeh
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestraße 70, 80336, Munich, Germany
| | - Marcus Zimmermann
- Division of Computerized Restorative Dentistry, Clinic of Conservative and Preventive Dentistry, Center of Dental Medicine, University of Zurich, Plattenstrasse 11, 8032, Zurich, Switzerland
| | - Bogna Stawarczyk
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestraße 70, 80336, Munich, Germany
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Deste Gökay G, Oyar P, Durkan R. Impact of various aging treatments on the microhardness and surface roughness of CAD-CAM monolithic restorative materials. J Prosthodont 2024. [PMID: 38638109 DOI: 10.1111/jopr.13846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 03/05/2024] [Indexed: 04/20/2024] Open
Abstract
PURPOSE Dental ceramics deteriorate as a result of thermal aging and exposure to acidic solutions, which change their microhardness and surface roughness. This study assessed the resistance of several computer-aided design and computer-aided manufacturing (CAD-CAM) restorative dental materials in terms of surface roughness and microhardness following exposure to acidic solutions and thermal aging. MATERIALS AND METHODS Five different monolithic CAD-CAM restorative materials, two leucite-reinforced glass ceramics (G-Ceram and CEREC Blocs), a zirconia-infiltrated lithium silicate (Celtra Duo), a resin nanoceramic (Grandio), and monolithic zirconia (inCoris TZI), were used to create 2-mm-thick rectangular specimens (n = 100). After being immersed in either acidic saliva (pH = 4.0) (ST) or gastric juice (pH = 1.2) (GT), each material was subjected to 10,000 cycles of thermal aging. The Vickers microhardness and average surface roughness of the specimens were assessed at baseline, following thermal aging and exposure to either gastric juice or acidic saliva. The surface properties were examined using an atomic force microscope. The Mann‒Whitney U test with Bonferroni correction and the Wilcoxon signed-rank test was used for statistical analysis (a = 0.05). RESULTS The surface roughness of two leucite-reinforced glass ceramics (G-ceram and CEREC) significantly decreased with ST (p = 0.027 and p = 0.044). Only the CEREC was affected when the aging protocols were compared, and the ST group had a significant reduction in roughness (p = 0.009). The microhardness values significantly decreased after both aging protocols in all groups except for the ST subgroup of G-Ceram. Only inCoris was affected when the aging protocols were compared, and the GT group exhibited a significant reduction in microhardness (p = 0.002). CONCLUSION The surface roughness of the tested materials was not affected by the GT. Only leucite ceramics exhibited a decrease in surface roughness in the ST stage. Both aging processes produced a significant decrease in the microhardness of the tested ceramics. Leucite-reinforced glass-ceramic materials may be advantageous for patients with gastroesophageal reflux disease and those with a diet high in acidic foods due to their lower values for changes in microhardness and surface roughness compared to those of other CAD-CAM materials.
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Affiliation(s)
- Gonca Deste Gökay
- Faculty of Dentistry, Department of Prosthodontics, Bursa Uludağ University, Bursa, Türkiye
| | - Perihan Oyar
- Dental Prosthetics Technology, School of Health Services, Hacettepe University, Ankara, Türkiye
| | - Rukiye Durkan
- Faculty of Dentistry, Department of Prosthodontics, Istanbul Okan University, Istanbul, Türkiye
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Yousry M, Hammad I, Halawani ME, Aboushelib M. Translucency of recent zirconia materials and material-related variables affecting their translucency: a systematic review and meta-analysis. BMC Oral Health 2024; 24:309. [PMID: 38443872 PMCID: PMC10913643 DOI: 10.1186/s12903-024-04070-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2024] [Accepted: 02/25/2024] [Indexed: 03/07/2024] Open
Abstract
BACKGROUND Recent forms of translucent zirconia material have been developed, offering a wide range of options and varieties for enhancing aesthetics, making it a preferred choice in the field of prosthetic dentistry. However, there is insufficient understanding regarding the recent types of zirconia materials and their optical behavior. Understanding the variables that influence the translucency of zirconia and identifying strategies to enhance its esthetics are crucial. PURPOSE The current systemic review highlights a comprehensive understanding of different zirconia generations in relation to their optical characteristics and evaluates material-related variables affecting their translucency. METHODS The present review studied in-vitro studies that evaluated the optical characteristics of different yttria content of yttria stabilized materials. The topics explored were: (1) the different zirconia material generations and their optical behavior; (2) material-related factors that affect their translucency. The research was restricted to online publication in the English language from July 1, 2010, to July 31, 2023, using PubMed, Scopus, and Science Direct resources. The search key terms and their combinations were "zirconia," "translucent zirconia," "cubic zirconia," "highly translucent zirconia," "yttria partially stabilized zirconia," "monolithic zirconia," "translucency," "optical properties," and "light transmission." RESULTS The data obtained from fifty-three studies addressed the optical characteristics of various zirconia generations. They reported that changing yttria content had a significant impact on translucency. Different kinds of zirconia ceramics of the same generation have varying translucencies. Achieving optimum aesthetics with monolithic zirconia is challenging due to factors related to material aspects such as the presence of additives, point defects, microstructure, thickness, phase distribution, and sintering conditions. CONCLUSIONS Newly developed monolithic dental zirconia ceramics have improved aesthetics and translucency. However, additional research is necessary to evaluate their performance and long-term durability. TRIAL REGISTRATION This systematic review was registered in PROSPERO, under number CRD42023474482.
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Affiliation(s)
- Mahinour Yousry
- Department of Conservative Dentistry, Faculty of Dentistry, Alexandria University, Alexandria, Egypt.
| | - Ihab Hammad
- Department of Conservative Dentistry, Faculty of Dentistry, Alexandria University, Alexandria, Egypt
| | - Mohamed El Halawani
- Department of Conservative Dentistry, Faculty of Dentistry, Alexandria University, Alexandria, Egypt
| | - Moustafa Aboushelib
- Department of Dental Materials Science, Faculty of Dentistry, Alexandria University, Alexandria, Egypt
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Labetić A, Klaser T, Skoko Ž, Jakovac M, Žic M. Flexural Strength and Morphological Study of Different Multilayer Zirconia Dental Materials. MATERIALS (BASEL, SWITZERLAND) 2024; 17:1143. [PMID: 38473614 DOI: 10.3390/ma17051143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 02/14/2024] [Accepted: 02/19/2024] [Indexed: 03/14/2024]
Abstract
Nowadays, yttria (Y3+)-stabilized ZrO2 (Y-TZP) is the most commonly used material in dental prosthetics. Y-TZP dental ceramics are mainly stabilized via the addition of 3 mol% yttrium oxide (Y2O3). These ceramics exhibit excellent mechanical properties, including high flexural strength, fracture toughness, elastic modulus, etc. Some manufacturers have recently introduced a new class of dental materials with multilayer composition with the aim of combining the advantages of adding more or less Y2O3 to the ceramic composition in one Y-TZP material. The flexural strength values of multilayer Y-TZP may vary depending on the dimensions of the specimen, layer distributions, and especially the layer exposed on the maximum tension side, i.e., loading configuration. Although previous studies have examined the flexural strength of separate Y-TZP layers, capturing the flexural strength of multilayer Y-TZP is still challenging. However, one should keep in mind that multilayer flexural strength is important for clinical indications. The objective of this study is to compare the flexural strength of three distinct multilayer translucent Y-TZP materials made up of layers with different Y3+ contents. Rectangular samples (2 mm × 2 mm × 16 mm) were prepared from CAD/CAM discs using the milling machine Programill PM7 (Ivoclar Vivadent AG). Milled bars were tested for flexural strength in a three-point bending test (ISO 6872:2015) using a universal testing machine (Inspekt Duo 5kN; Hegewald & Peschke, Nossen, Germany) at a crosshead speed of 0.5 mm/min. Representative samples of each type of material were selected for quantitative and qualitative analysis of the microstructure. Representative samples of each type of material were selected for structural, mechanical, and microstructural analyses.
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Affiliation(s)
- Andrea Labetić
- University of Zagreb School of Dental Medicine, Gunduliceva 5, 10000 Zagreb, Croatia
| | - Teodoro Klaser
- Ruder Boskovic Institute, P.O. Box 180, 10000 Zagreb, Croatia
| | - Željko Skoko
- Department of Physics, Faculty of Science, University of Zagreb, Bijenicka, c. 32, 10000 Zagreb, Croatia
| | - Marko Jakovac
- University of Zagreb School of Dental Medicine, Gunduliceva 5, 10000 Zagreb, Croatia
| | - Mark Žic
- Ruder Boskovic Institute, P.O. Box 180, 10000 Zagreb, Croatia
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Edelhoff D, Schubert O, Stimmelmayr M, Schweiger J. CAD/CAM full-mouth rehabilitation of an elderly patient: One-piece digital complete denture meets multilayered zirconia with gradient technology. J ESTHET RESTOR DENT 2024; 36:174-185. [PMID: 36866726 DOI: 10.1111/jerd.13031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 02/02/2023] [Accepted: 02/11/2023] [Indexed: 03/04/2023]
Abstract
OBJECTIVE This article highlights a CAD/CAM complete-mouth rehabilitation in an 82-year-old patient by means of a complete maxillary prosthesis and mandibular implant- and tooth-supported fixed restorations made from multilayered zirconia. CLINICAL CONSIDERATIONS Comprehensive complete-mouth rehabilitations in elderly patients with adaptation of the occlusal vertical dimension (OVD) often present particular challenges. This applies especially when exacting functional and esthetic requirements are to be met and the treatment should not cause the patient too much effort, still ensuring the highest level of quality and efficiency and a low intervention rate. CONCLUSION The digital approach used for the present patient allowed for an efficient treatment procedure, facilitated virtual evaluations using a face-scan, and enhanced the predictability of the prosthodontic outcome. The approach enabled some steps required in the conventional protocol to be omitted, resulting in a straightforward clinical treatment with minimal strain on the patient. CLINICAL SIGNIFICANCE Because of the comprehensive recording of extraoral and intraoral data, for example with a facial scanner, it was possible to transfer a digital replica of the patient to the dental laboratory technician. With this protocol, many steps can be performed in the absence of the real patient.
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Affiliation(s)
- Daniel Edelhoff
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Munich, Germany
| | - Oliver Schubert
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Munich, Germany
| | - Michael Stimmelmayr
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Munich, Germany
| | - Josef Schweiger
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Munich, Germany
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Radwan MM, Abdou A, Nagi N, Younes DH, Mahrous A. Wear characteristics of esthetic resin matrix and zirconia reinforced lithium disilicate CAD/CAM materials: two-body wear and surface topography analysis. Minerva Dent Oral Sci 2023; 72:280-290. [PMID: 37255305 DOI: 10.23736/s2724-6329.23.04779-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
BACKGROUND This in vitro study assessed the wear behavior of different CAD-CAM blocks and the abrasion of the enamel antagonist against these materials. METHODS 64 disk-shaped specimens were prepared from 8 different CAD/CAM blocks as follow: one lithium disilicate glass ceramics block "IPS Emax CAD" as control group, two zirconia reinforced lithium silicate "Vita Suprinity & Celtra DUO," one interpenetrating network ceramic block "Vita Enamic," Three resin-based block composites "Lava Ultimate, Cerasmart & Brilliant-crios" as well as one hybrid nanoceramic "Shofu block HC". All specimens were mounted against canine and tested for two body wear analysis using a chewing simulating loading machine (100,000 cycles, 50 N, 5/55 °C). The amount of wear loss was measured for each specimen using a digital precise scale. Wear area before and after the chewing simulation were evaluated using an optical profilometer. Data analysed using one-way ANOVA test followed by Tukey's post hoc. RESULTS The results showed a significantly higher wear loss in resin matrix ceramics in comparison to glass ceramics. However, for tooth wear glass ceramics had significantly higher value than hybrid ceramics. CONCLUSIONS Resin based CAD/CAM Blocks gives a superior result when evaluating the wear behavior and its effect on the opposing tooth surface.
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Affiliation(s)
- Mohamed M Radwan
- Department of Fixed Prosthodontics, Faculty of Dentistry, Bani-Suef University, Bani-Suef, Egypt
| | - Ahmed Abdou
- Department of Prosthetic Dentistry, Faculty of Dentistry, King Salman International University, El Tur, Egypt -
| | - Nermeen Nagi
- Department of Fixed Prosthodontics, Faculty of Dentistry, Fayoum University, Fayoum, Egypt
| | - Dina H Younes
- Department of Oral Medicine, Periodontology, Oral Diagnosis and Radiology, Faculty of Dentistry, University of Zagazig, Zagazig, Egypt
| | - Aliaa Mahrous
- Department of Fixed Prosthodontics, Faculty of Dentistry, Fayoum University, Fayoum, Egypt
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Miura S, Shinya A, Ishida Y, Fujita T, Vallittu P, Lassila L, Fujisawa M. The effect of low-temperature degradation and building directions on the mechanical properties of additive-manufactured zirconia. Dent Mater J 2023; 42:800-805. [PMID: 37793824 DOI: 10.4012/dmj.2023-089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/06/2023]
Abstract
This study aimed to investigate the effect of low-temperature degradation (LTD) on the mechanical properties of additive-manufactured zirconia. In addition, the mechanical properties of additive-manufactured were compared with those before aging under similar experimental conditions. This study prepared stereolithography apparatus fabricated zirconia specimens with flexural strength, modulus of elasticity, Vickers hardness, and fracture toughness. The specimen position data were set as parallel (0°), diagonal (45°), and perpendicular (90°) to the direction of the building. The LTD condition was 5 h under 134ºC and 0.2 MPa in an autoclave. It was found that the 0° direction differed significantly from all other conditions before and after aging, and the highest flexural strength was obtained when the additive specimen was manufactured perpendicular to the building direction. However, the results indicate that there is a negligible effect of aging on the mechanical properties of additive-manufactured zirconia.
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Affiliation(s)
- Shoko Miura
- Division of Fixed Prosthodontics, Department of Restorative and Biomaterials Sciences, Meikai University School of Dentistry
- Department of Biomaterials Science and Turku Clinical Biomaterials Center-TCBC, Institute of Dentistry, University of Turku
| | - Akikazu Shinya
- Department of Dental Materials Sciences, School of Life Dentistry at Tokyo, The Nippon Dental University
- Department of Prosthetic Dentistry and Biomaterials Science, Institute of Dentistry, University of Turku
| | - Yoshiki Ishida
- Department of Dental Materials Sciences, School of Life Dentistry at Tokyo, The Nippon Dental University
| | - Takafumi Fujita
- Division of Fixed Prosthodontics, Department of Restorative and Biomaterials Sciences, Meikai University School of Dentistry
| | - Pekka Vallittu
- Department of Biomaterials Science and Turku Clinical Biomaterials Center-TCBC, Institute of Dentistry, University of Turku
- Department of Prosthetic Dentistry and Biomaterials Science, Institute of Dentistry, University of Turku
- Welfare District of County of Southwest Finland
| | - Lippo Lassila
- Department of Biomaterials Science and Turku Clinical Biomaterials Center-TCBC, Institute of Dentistry, University of Turku
| | - Masanori Fujisawa
- Division of Fixed Prosthodontics, Department of Restorative and Biomaterials Sciences, Meikai University School of Dentistry
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Refaie A, Bourauel C, Fouda AM, Keilig L, Singer L. The effect of cyclic loading on the fracture resistance of 3D-printed and CAD/CAM milled zirconia crowns-an in vitro study. Clin Oral Investig 2023; 27:6125-6133. [PMID: 37615777 PMCID: PMC10560138 DOI: 10.1007/s00784-023-05229-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 08/17/2023] [Indexed: 08/25/2023]
Abstract
OBJECTIVES The aim of this study was to evaluate the effect of cyclic mechanical loading on the fracture resistance of 3D-printed zirconia crowns in comparison to milled zirconia crowns. MATERIALS AND METHODS Monolithic zirconia crowns (n = 30) were manufactured using subtractive milling (group M) and 3D additive printing (group P). Nine samples of each group were fractured under one-time loading while the other 6 samples were subjected to cyclic loading for 1.2 million cycles before being subjected to one-time loading until fracture. Scanning electron microscope (SEM) fractographic analysis was carried out on fractured fragments of representative samples. RESULTS The mean for fracture resistance of group M was 1890 N without cyclic loading and 1642 N after being subjected to cyclic loading, and they were significantly higher than that of group P (1658 N and 1224 N respectively). CONCLUSIONS The fabrication technique and cyclic loading affect the fracture resistance of zirconia crowns. Although the fracture resistance values for the 3D-printed crowns were lower than those of the milled, still they are higher than the masticatory forces and thus could be considered being clinically acceptable. CLINICAL RELEVANCE Concerning fracture resistance, 3D-printed crowns can withstand the masticatory forces for the long term without any cracks or failure.
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Affiliation(s)
- Ashraf Refaie
- Oral Technology, Dental School, Medical Faculty, University Hospital of Bonn, Welschnonnenstr. 17, 53111, Bonn, North Rhine-Westphalia, Germany.
- Department of Fixed Prosthodontics, Faculty of Dentistry, Fayoum University, Faiyum, Egypt.
| | - Christoph Bourauel
- Oral Technology, Dental School, Medical Faculty, University Hospital of Bonn, Welschnonnenstr. 17, 53111, Bonn, North Rhine-Westphalia, Germany
| | - Ahmed Mahmoud Fouda
- Oral Technology, Dental School, Medical Faculty, University Hospital of Bonn, Welschnonnenstr. 17, 53111, Bonn, North Rhine-Westphalia, Germany
- Suez Canal University, Ismailia, Egypt
| | - Ludger Keilig
- Oral Technology, Dental School, Medical Faculty, University Hospital of Bonn, Welschnonnenstr. 17, 53111, Bonn, North Rhine-Westphalia, Germany
- Department of Prosthodontics, Preclinical Education and Dental Materials Science, Dental School, Medical Faculty, University Hospital of Bonn, 53111, Bonn, North Rhine-Westphalia, Germany
| | - Lamia Singer
- Oral Technology, Dental School, Medical Faculty, University Hospital of Bonn, Welschnonnenstr. 17, 53111, Bonn, North Rhine-Westphalia, Germany
- Department of Orthodontic, Dental School, Medical Faculty, University Hospital of Bonn, 53111, Bonn, North Rhine-Westphalia, Germany
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Wille S, Möller R, Kern M. Influence of shading on zirconia's phase transformation and flexural strength after artificial aging. Dent Mater 2023; 39:702. [PMID: 37385942 DOI: 10.1016/j.dental.2023.06.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 05/17/2023] [Accepted: 06/14/2023] [Indexed: 07/01/2023]
Abstract
OBJECTIVES The aim of this study was to determine the phase transformation and the influence of aging on the flexural strength of different colored zirconia. The effect of hydrothermal aging in an autoclave was compared with the effect of mechanical stress by simulating chewing. METHODS High-strength zirconia (3Y-TZP) was investigated in three different colors: uncolored, A3, and D3. Disc-shaped specimens (N = 3) were analyzed by X-ray diffraction (XRD), and flexural strength was determined on bar-shaped specimens (N = 15) in a 4-point bending test before and after performing two different aging protocols: aging in an autoclave (134 °C, 70 h) and aging in a chewing simulator (5 kg load, 1.2 million cycles). During autoclave aging, the fraction of monoclinic phase on the surface was determined every 5 h. Once this exceeded 25 vol%, aging of the bar specimens was stopped. RESULTS While in the unstained group the mean value of the proportion of monoclinic phase already exceeded 25 vol% after 30 h in the autoclave, this was the case in both stained groups only after 70 h. No measurable phase transformation could be detected after chewing simulation. Only color A3 showed a statistically significant (p ≤ 0.05) decrease in flexural strength after aging in the chewing simulator. SIGNIFICANCE The colored zirconia showed a higher resistance to phase transformation through hydrothermal aging. The metal oxides in the staining solutions are assumed to hinder the phase transformation in the zirconia. Therefore, the significant reduction in the stained zirconia after chewing simulation is particularly interesting.
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Affiliation(s)
- Sebastian Wille
- Department of Prosthodontics, Propaedeutics and Dental Materials, School of Dentistry, Christian-Albrechts University at Kiel, Germany.
| | - Rüdiger Möller
- Department of Prosthodontics, Propaedeutics and Dental Materials, School of Dentistry, Christian-Albrechts University at Kiel, Germany.
| | - Matthias Kern
- Department of Prosthodontics, Propaedeutics and Dental Materials, School of Dentistry, Christian-Albrechts University at Kiel, Germany.
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Oyar P, Durkan R. The effects of heating rate and sintering time on the biaxial flexural strength of monolithic zirconia ceramics. BIOMED ENG-BIOMED TE 2023:bmt-2022-0338. [PMID: 36930871 DOI: 10.1515/bmt-2022-0338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 03/02/2023] [Indexed: 03/19/2023]
Abstract
The strength of zirconia ceramic materials used in restorations is dependent upon sintering. Varying sintering protocols may affect the biaxial flexural strength of zirconia materials. This in vitro study was conducted to investigate the effects of sintering parameters on the biaxial flexural strength of monolithic zirconia. Two different monoblock zirconia ceramics were used. Following coloration, samples of both types of ceramics were divided into groups according to whether or not biaxial flexural strength testing was performed directly after sintering or following thermocycling. Biaxial flexural strength data was analysed with a Shapiro Wilk normality test, followed by 1-way ANOVA, Tukey post hoc tests for inter-group comparisons, and paired samples t-tests for intra-group comparisons. A significant difference was found between the biaxial flexural strengths of Zircon X and Upcera ceramics before thermocycling (p<0.05). In both Zircon X and Upcera ceramic groups, the thermocycling process created a significant difference in the biaxial flexural strength values of the ceramic samples in Group 6 (p<0.05) which had the slowest heating rate and longest holding time. The zirconia ceramics have higher BFS at higher heating rates either before or after thermocycling. The holding time has significant effects on thermocycling and flexural strength. The zirconia achieved its optimum strength when it sintered at longer time regardless of heating rates.
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Affiliation(s)
- Perihan Oyar
- Professor, Dental Prosthetics Technology, Vocational School of Health Services, Hacettepe University, Ankara, Türkiye
| | - Rukiye Durkan
- Department of Prosthodontics, Faculty of Dentistry, Istanbul Okan University, Istanbul, Türkiye
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Ozdogan A, Tosun B. Effects of repetitive firings on mechanical, optical, and phase formation changes of ceramic materials. J Prosthet Dent 2023:S0022-3913(23)00103-8. [PMID: 36889999 DOI: 10.1016/j.prosdent.2023.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 02/02/2023] [Accepted: 02/02/2023] [Indexed: 03/09/2023]
Abstract
STATEMENT OF PROBLEM Studies are sparse on how rapid heating and cooling negatively affect optical properties, including color and transparency, and mechanical properties, including hardness and durability, that affect esthetics and shorten the clinical usage period of the ceramics. PURPOSE The purpose of this in vitro study was to determine the effects of repeated firing on the color difference, mechanical properties, and phase formation of different ceramic materials. MATERIAL AND METHODS A total of 160 disks (12×1.35 mm) were produced from 4 different ceramic materials: lithium disilicate glass-ceramic, zirconia-reinforced lithium silicate ceramic, zirconia core, and monolithic zirconia. Specimens from all groups were divided into 4 groups (n=10) with a different number of veneer porcelain firings (1 to 4) by simple randomization. After the firings, color measurement, X-ray diffraction analysis, environmental scanning electron micrograph analysis, surface roughness evaluation, Vickers hardness evaluation, and biaxial flexural strength tests were performed. Data were analyzed with analysis of variance (2-way ANOVA) (α=.05). RESULTS Repeated firing did not affect the flexural strength of the specimens in any of the groups (P>.05), while the color, surface roughness, and surface hardness were significantly affected (P<.05). The specimens fired 4 times showed the highest mean Vickers hardness and ΔE00 values but the lowest mean surface roughness values. Zirconia core specimens showed the highest mean ΔE00 and flexural strength values, and lithium disilicate glass-ceramic specimens had the highest mean Vickers hardness values. CONCLUSIONS The increase in the number of firings affected the color, mechanical properties, and phase formation of the specimens; this change differed according to the ceramic tested.
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Affiliation(s)
- Alper Ozdogan
- Associate Professor, Department of Prosthodontics, Faculty of Dentistry, Atatürk University, Erzurum, Turkey.
| | - Büsra Tosun
- Assistant Professor, Department of Prosthodontics, Faculty of Dentistry, Bolu Abant İzzet Baysal University, Bolu, Turkey
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Çakmak G, Subaşı MG, Sert M, Yilmaz B. Effect of surface treatments on wear and surface properties of different CAD-CAM materials and their enamel antagonists. J Prosthet Dent 2023; 129:495-506. [PMID: 34301415 DOI: 10.1016/j.prosdent.2021.06.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 06/15/2021] [Accepted: 06/15/2021] [Indexed: 10/20/2022]
Abstract
STATEMENT OF PROBLEM Which surface treatment provides optimal surface roughness, microhardness, and wear behavior for computer-aided design and computer-aided manufacturing (CAD-CAM) materials and their enamel antagonists is unclear. PURPOSE The purpose of this in vitro study was to evaluate the effect of surface treatment on the surface roughness, microhardness, and 2-body wear of different CAD-CAM materials and their enamel antagonists. MATERIAL AND METHODS Monolithic zirconia, polymer-infiltrated ceramic network, lithium disilicate, leucite-reinforced ceramic, zirconia-reinforced lithium silicate, and feldspathic ceramic specimens were sliced into 2-mm-thick rectangular plates and divided into polished or glazed subgroups (n=6). After surface roughness and microhardness measurements, the specimens were loaded at 49 N for 250 000 cycles and simultaneously thermocycled (5 °C and 55 °C). All specimens were scanned before and after the wear test by using a scanner. The volumetric loss and wear depth of the materials and the volumetric and height loss of the enamel were calculated, and scanning electron microscope images of the specimens were made. Multiple 2-way ANOVAs and Tukey honestly significant difference tests were used to assess the effect of material and surface treatment on surface roughness, microhardness, and wear behavior of materials and enamel (α=.05). RESULTS Material and surface treatment interactions affected the surface roughness (P<.001), microhardness (P<.001), volumetric loss of materials (P=.044), and height loss of enamel (P<.001). CONCLUSIONS Polishing resulted in higher surface roughness and microhardness than glazing. Volumetric loss depended on the material, which affected the height loss of the antagonists. Glazing and polishing had similar effects on the volumetric loss of materials and antagonists. No correlation was found between the wear of materials and the antagonists, nor between the surface roughness of materials and the volumetric loss of materials or antagonists.
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Affiliation(s)
- Gülce Çakmak
- Buser Foundation Scholar for Implant Dentistry, Department of Reconstructive Dentistry and Gerodontology, School of Dental Medicine, University of Bern, Bern, Switzerland.
| | - Meryem Gülce Subaşı
- Associate Professor, Department of Prosthodontics, Faculty of Dentistry, Kütahya Sağlık Bilimleri University, Kütahya, Turkey
| | - Murat Sert
- Assistant Professor, Department of Medical Laboratory Techniques, Ankara Yildirim Beyazit University, Ankara, Turkey
| | - Burak Yilmaz
- Associate Professor, Department of Reconstructive Dentistry and Gerodontology, School of Dental Medicine, University of Bern, Bern, Switzerland; Associate Professor, Department of Restorative, Preventive and Pediatric Dentistry, School of Dental Medicine, University of Bern, Bern, Switzerland; Adjunct Professor, Division of Restorative and Prosthetic Dentistry, The Ohio State University, Columbus, Ohio
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13
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Krüger S, Wille S, Kern M. The Correlation of Surface Roughness Parameters of Zirconia and Lithium Disilicate with Steatite Wear. J Prosthodont 2023; 32:e52-e63. [PMID: 35771977 DOI: 10.1111/jopr.13562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Accepted: 06/14/2022] [Indexed: 11/30/2022] Open
Abstract
PURPOSE Various surface roughness parameters are utilized to describe the surface in the tooth to ceramics abrasion and to assess the resulting wear. The use of three-dimensional parameters may offer a better estimation for wear and an improved deduced clinical surface treatment. The aim of this study was to determine the influence of various surface roughness parameters of zirconia and lithium disilicate ceramics on the wear of steatite antagonists. MATERIAL AND METHODS Forty zirconia specimens with a diameter of 7 mm and a thickness of 3 mm and 40 lithium disilicate specimens with the dimensions 10×10×4 mm were each divided into five subgroups. Two subgroups were treated with different clinically established diamond burs; a third subgroup was treated with a silicone polishing set. Two additional subgroups were produced by glazing the surfaces after treatment. Surface roughness parameters were determined by laser scanning microscopy. All specimens underwent 1.2 million loading cycles using steatite antagonists. After regular intervals of cycles, precision impressions were made to assess the wear. The correlation between wear and different roughness parameters was evaluated using the Spearman correlation test. RESULTS For the glazed zirconia, unglazed zirconia, and glazed lithium disilicate specimens no significant correlations (p > 0.05) between the investigated roughness parameters and antagonist wear could be found. In the unglazed lithium disilicate groups, significant (p ≤ 0.05) correlations with steatite substance loss could be found for several roughness parameters after 1.2 million cycles. CONCLUSIONS For lithium disilicate, it seems not sufficient to use only one roughness parameter to indicate the wear behavior of the surface. There was no correlation between wear and the tested roughness parameters of zirconia surfaces.
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Affiliation(s)
- Stephan Krüger
- Department of Prosthodontics, Propaedeutics and Dental Materials, School of Dentistry, Christian-Albrechts University, Kiel, Germany
| | - Sebastian Wille
- Department of Prosthodontics, Propaedeutics and Dental Materials, School of Dentistry, Christian-Albrechts University, Kiel, Germany
| | - Matthias Kern
- Department of Prosthodontics, Propaedeutics and Dental Materials, School of Dentistry, Christian-Albrechts University, Kiel, Germany
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Singh RG, Lyons KM, Waddell JN, Li KC. Effect of thermocycling on the mechanical properties, inorganic particle release and low temperature degradation of glazed high translucent monolithic 3Y-TZP dental restorations. J Mech Behav Biomed Mater 2022; 136:105495. [PMID: 36208582 DOI: 10.1016/j.jmbbm.2022.105495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 09/27/2022] [Accepted: 09/27/2022] [Indexed: 11/24/2022]
Abstract
The influence of thermocycling on the surface deterioration of glazed monolithic high translucent 3Y-TZP dental restorations is still unclear. The purpose of this study therefore was to evaluate low temperature degradation (LTD), elemental release and surface degradation pattern after five years of simulated clinical time. A total of 123 specimens were prepared from second-generation high translucent 3Y-TZP as per ISO 6872:2015 standards (3 mm × 4 mm × 30 mm). They were classified as per glazing and thermocycling protocol; group CPT, DGT and IGT. Glaze materials were applied on one surface of the specimen and subjected to a thermocycling in artificial saliva, four-point bending test, inductively coupled plasma mass spectrometry (ICP-MS), scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDX) and x-ray diffraction (XRD). Flexural strength, characteristic strength and Weibull modulus values were derived from four-point bending test. Descriptive fractographic analysis of surfaces was conducted to observe the surface degradation characteristics and point of failure. Control/no glaze with thermocycling (CPT = 621.5, 1σ = 117.0 MPa) presented higher flexural strength values compared to glaze I with thermocycling (442.4, 1σ = 45.4 MPa) and glaze II with thermocycling (534.3, 1σ = 46.3 MPa). Characteristic strength from Weibull analysis also observed higher values (669.2 MPa) for the control specimens. XRD analysis showed that monoclinic volume fraction (Vm = 11.0, 1σ = 0.7%) was highest in control specimens. Fractographic analysis suggested that there was no correlation between the point of failure initiation and mean flexural strength values. Glazing protected the high translucent 3Y-TZP surface against LTD during thermocycling but negatively impacted on the flexural strength.
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Affiliation(s)
- Raj Gaurav Singh
- Department of Oral Rehabilitation, Faculty of Dentistry, University of Otago, New Zealand.
| | - Karl Michael Lyons
- Department of Oral Rehabilitation, Faculty of Dentistry, University of Otago, New Zealand.
| | - John Neil Waddell
- Department of Oral Rehabilitation, Faculty of Dentistry, University of Otago, New Zealand.
| | - Kai Chun Li
- Department of Oral Rehabilitation, Faculty of Dentistry, University of Otago, New Zealand.
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15
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Bocam K, Anunmana C, Eiampongpaiboon T. Grain size, crystalline phase and fracture toughness of the monolithic zirconia. J Adv Prosthodont 2022; 14:285-293. [PMID: 36452361 PMCID: PMC9672698 DOI: 10.4047/jap.2022.14.5.285] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 09/03/2022] [Accepted: 09/22/2022] [Indexed: 08/27/2023] Open
Abstract
PURPOSE This study evaluated the relationship among translucency, crystalline phase, grain size, and fracture toughness of zirconia. MATERIALS AND METHODS Four commercial zirconia - Prettau®Anterior® (PA), Prettau® (P), InCorisZI (ZI), and InCorisTZI (TZI)- were selected for this study. The bar specimens were prepared to determine fracture toughness by using chevron notched beam method with four-point bending test. The grain size was evaluated by a mean linear intercept method using a scanning electron microscope. X-ray diffraction and Rietveld refinement were performed to evaluate the amount of tetragonal and cubic phases of zirconia. Contrast ratio (CR) was measured to investigate the level of translucency. RESULTS PA had the lowest fracture toughness among other groups (P < .05). In addition, the mean fracture toughness of P was significantly less than that of ZI, but there was no difference compared with TZI. Regarding grain size measurement, PA had the largest average grain size among the groups. P obtained larger grain size than ZI and TZI (P < .05). However, there was no significant difference between ZI and TZI. Moreover, PA had the lowest CR value compared with the other groups (P < .05). This means PA was the most translucent material in this study. Rietveld refinement found that PA presented the greatest percentage of cubic phase, followed by TZI, ZI, and P, respectively. CONCLUSION The different approaches are used by manufacturers to fabricate various types of translucent zirconia with different levels of translucency and mechanical properties, which should be concerned for material selection for successful clinical outcome.
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Affiliation(s)
- Kodchakorn Bocam
- Residency Training Program, Department of Prosthodontics, Faculty of Dentistry, Mahidol University, Bangkok, Thailand
| | - Chuchai Anunmana
- Department of Prosthodontics, Faculty of Dentistry, Mahidol University, Bangkok, Thailand
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16
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Park JH, Bang HJ, Choi NH, Park EJ. Translucency and masking ability of translucent zirconia; comparison with conventional zirconia and lithium disilicate. J Adv Prosthodont 2022; 14:324-333. [PMID: 36452362 PMCID: PMC9672692 DOI: 10.4047/jap.2022.14.5.324] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 10/12/2022] [Accepted: 10/17/2022] [Indexed: 01/12/2024] Open
Abstract
PURPOSE The purpose of this study is to evaluate translucency and masking ability of translucent zirconia compared to conventional zirconia and lithium disilicate materials. MATERIALS AND METHODS Three types of zirconia blocks with different yttria contents (3Y, 4Y, 5.5Y) and LS blocks (Rosetta SM) were used. Ten specimens for each group were fabricated with 10 mm diameter, with both 0.8 mm and 1.5 mm thicknesses (± 0.02 mm). All groups of zirconia specimens were sintered and polished according to the manufacturer's instructions. To calculate the translucency parameter (TP), CIELAB value was measured with a spectrophotometer on black and white backgrounds. To investigate the color masking abilities, background shades of A2, normal dentin, discolored dentin, and titanium were used. The color difference (ΔE) was calculated with the CIELAB values of A2 shade background as a reference compared with the values in the various backgrounds. One-way ANOVA and Bonferroni tests were conducted (P < .05). RESULTS The TP values of zirconia specimens increased as the yttria content increased. All materials used in the study were able to adequately mask normal dentin shade (ΔE < 5.5), but were incapable of masking severely discolored dentin (ΔE > 5.5). On the titanium background, all materials of 1.5 mm thickness were able to mask the background shade, but with a thickness of 0.8 mm, only 3Y-TZP and 4Y-PSZ were able to mask titanium background. CONCLUSION All zirconia materials and lithium disilicate specimens used in this study were unable to adequately mask the shade of severely discolored dentin. It is recommended to use 3Y-TZP or 4Y-PSZ with a sufficient thickness of 0.8 mm or more to mask titanium.
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Affiliation(s)
- Joon Hee Park
- Department of Prosthodontics, School of Medicine, Ewha Womans University, Seoul, Republic of Korea
| | | | - Nak-Hyun Choi
- Yonsei Design Dental Clinic, Seoul, Republic of Korea
| | - Eun-Jin Park
- Department of Prosthodontics, School of Medicine, Ewha Womans University, Seoul, Republic of Korea
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Elraggal A, Aboushelib M, Abdel Raheem IM, Afifi RR. Effect of surface treatments on biaxial flexural strength, fatigue resistance, and fracture toughness of high versus low translucency zirconia. BMC Oral Health 2022; 22:412. [PMID: 36123676 PMCID: PMC9487058 DOI: 10.1186/s12903-022-02431-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Accepted: 09/05/2022] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Mechanical surface treatments can deteriorate the mechanical properties of zirconia. This study evaluated and compared the biaxial flexural strength, fracture toughness, and fatigue resistance of high translucency (HT) to low translucency (LT) zirconia after various mechanical surface treatments. METHODS Four hundred eighty zirconia discs were prepared by milling and sintering two HT (Katana and BruxZir) and LT (Cercon and Lava) zirconia blocks at targeted dimensions of 12 mm diameter × 1.2 mm thickness. Sintered zirconia discs received one of the following surface treatments: low-pressure airborne particle abrasion (APA) using 50 µm alumina particles, grinding using 400 grit silicon carbide paper, while as-sintered specimens served as control. Internal structure and surface roughness were evaluated by scanning electron microscope (SEM) and a non-contact laser profilometer, respectively. Half of the discs were tested for initial biaxial flexural strength, while the rest was subjected to 106 cyclic fatigue loadings, followed by measuring the residual biaxial flexural strength. Fractured surfaces were examined for critical size defects (c) using SEM to calculate the fracture toughness (KIC). The effect of surface treatments, zirconia type, and cyclic fatigue on the biaxial flexural strength was statistically analyzed using three-way analysis of variance (ANOVA) and Tukey HSD post hoc tests (α = 0.05). Weibull analysis was done to evaluate the reliability of the flexural strength for different materials. RESULTS The initial biaxial flexural strength of LT zirconia was significantly higher (p < 0.001) than that of HT zirconia in all groups. While low APA significantly increased the biaxial flexural strength of LT zirconia, no significant change was observed for HT zirconia except for Katana. Surface grinding and cyclic fatigue significantly reduced the flexural strength of all groups. High translucency zirconia reported higher fracture toughness, yet with lower Weibull moduli, compared to LT zirconia. CONCLUSION LT zirconia has higher biaxial flexural strength, yet with lower fracture toughness and fatigue resistance, compared to HT zirconia. Low-pressure APA has significantly increased the biaxial flexural strength in all zirconia groups except BruxZir. Grinding was deteriorating to biaxial flexural strength and fracture toughness in all zirconia types. Cyclic fatigue has significantly decreased the biaxial flexural strength and reliability of HT and LT zirconia.
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Affiliation(s)
- Alaaeldin Elraggal
- Conservative Dentistry Department, Faculty of Dentistry, Alexandria University, Alexandria, Egypt.
| | - Moustafa Aboushelib
- grid.7155.60000 0001 2260 6941Dental Biomaterials Department, Faculty of Dentistry, Alexandria University, Alexandria, Egypt
| | - Islam M. Abdel Raheem
- grid.7155.60000 0001 2260 6941Conservative Dentistry Department, Faculty of Dentistry, Alexandria University, Alexandria, Egypt
| | - Rania R. Afifi
- grid.7155.60000 0001 2260 6941Conservative Dentistry Department, Faculty of Dentistry, Alexandria University, Alexandria, Egypt
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Rabel K, Nold J, Pehlke D, Shen J, Abram A, Kocjan A, Witkowski S, Kohal RJ. Zirconia fixed dental prostheses fabricated by 3D gel deposition show higher fracture strength than conventionally milled counterparts. J Mech Behav Biomed Mater 2022; 135:105456. [PMID: 36150323 DOI: 10.1016/j.jmbbm.2022.105456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 09/05/2022] [Accepted: 09/07/2022] [Indexed: 11/30/2022]
Abstract
Zirconia restorations, which are fabricated by additive 3D gel deposition and do not require glazing like conventional restorations, were introduced as "self-glazed" zirconia restorations into dentistry. This in vitro investigation characterized the surface layer, microstructure and the fracture and aging behavior of "self-glazed" zirconia (Y-TZPSG) three-unit fixed dental prostheses (FDP) and compared them to conventionally CAD/CAM milled and glazed controls (Y-TZPC-FDPs). For this purpose, the FDPs were analyzed by (focused ion beam) scanning electron microscopy, laserscanning microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction and a dynamic and static loading test. For the latter, half of the samples of each material group (n = 16) was subjected to 5 million cycles of thermocyclic loading (98N) in an aqueous environment in a chewing simulator. Afterwards, all FDPs were loaded to fracture. Y-TZPSG-FDPs demonstrated a comparable elemental composition but higher surface microstructural homogeneity and fracture strength compared to Y-TZPC-FDPs. Microstructural flaws within the FDPs' surfaces were identified as fracture origins. The high fracture strength of the Y-TZPSG-FDPs was attributed to a finer-grained microstructure with fewer surface flaws compared to the Y-TZPC-FDPs which showed numerous flaws in the glaze overlayer. A decrease in fracture strength after dynamic loading from 5165N to 4507N was observed for the Y-TZPSG-FDPs, however, fracture strength remained statistically significantly above the one measured for Y-TZPC-FDPs (before chewing simulation: 1923N; after: 2041N). Within the limits of this investigation, it can therefore be concluded that Y-TZPSG appears to be stable for clinical application suggesting further investigations to prove clinical applicability.
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Affiliation(s)
- Kerstin Rabel
- Department of Prosthetic Dentistry, Center for Dental Medicine, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Hugstetterstr. 55, 79106, Freiburg, Germany.
| | - Julian Nold
- Department of Prosthetic Dentistry, Center for Dental Medicine, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Hugstetterstr. 55, 79106, Freiburg, Germany
| | - Daniela Pehlke
- Department of Prosthetic Dentistry, Center for Dental Medicine, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Hugstetterstr. 55, 79106, Freiburg, Germany
| | - James Shen
- Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, Stockholm, Sweden
| | - Anže Abram
- Department for Nanostructured Materials, Jožef Stefan Institute, Jamova 39, SI-1000, Ljubljana, Slovenia
| | - Andraž Kocjan
- Department for Nanostructured Materials, Jožef Stefan Institute, Jamova 39, SI-1000, Ljubljana, Slovenia
| | - Siegbert Witkowski
- Department of Prosthetic Dentistry, Center for Dental Medicine, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Hugstetterstr. 55, 79106, Freiburg, Germany
| | - Ralf-Joachim Kohal
- Department of Prosthetic Dentistry, Center for Dental Medicine, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Hugstetterstr. 55, 79106, Freiburg, Germany
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Jia-Mahasap W, Jitwirachot K, Holloway JA, Rangsri W, Rungsiyakull P. Wear of various restorative materials against 5Y-ZP zirconia. J Prosthet Dent 2022; 128:814.e1-814.e10. [PMID: 36089544 DOI: 10.1016/j.prosdent.2022.07.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 07/26/2022] [Accepted: 07/27/2022] [Indexed: 11/26/2022]
Abstract
STATEMENT OF PROBLEM The ceramic 5-mol% yttria-stabilized zirconia (5Y-ZP) has been developed for dental use in the esthetic zone with greater translucency than 3-mol% yttria-stabilized zirconia (3Y-ZP). However, studies on the wear behavior of 5Y-ZP zirconia against clinically relevant antagonist materials are lacking. PURPOSE The purpose of this in vitro study was to investigate the wear behavior of 5Y-ZP zirconia against the antagonists 5Y-ZP zirconia, lithium disilicate, palladium alloy, and human enamel. MATERIALS AND METHODS Flat specimens (n=8) were fabricated from 5Y-ZP zirconia, lithium disilicate, palladium alloy, and human central incisor enamel. A custom wear-simulating device with a sliding pin-on-plate configuration was used for a total of 120 000 wear cycles at 1.6-Hz frequency under a 49-N vertical load while submerged in distilled water at room temperature. The wear volume and maximum wear depth of flat specimens were evaluated with a 3D profilometer. Scanning electron microscopy was used to analyze the characteristics of the worn surfaces. RESULTS After wear simulation, the 5Y-ZP zirconia and palladium-silver alloy specimens exhibited the least amount of material loss, both in terms of maximum wear depth and wear volume (0.079 ±0.042 μm, 0.001 ±0.001 mm3 and 0.637 ±0.307 μm, 0.001 ±0.000 mm3, respectively). This was followed by human enamel (6.034 ±1.086 μm, 0.009 ±0.001 mm3) and by lithium disilicate, which showed excessive material loss (38.342 ±2.569 μm, 0.213 ±0.024 mm3). Scanning electron microscopy revealed variations in wear mechanisms among the materials. CONCLUSIONS The 5Y-ZP zirconia and palladium-silver alloy exhibited the lowest wear, followed by human enamel and lithium disilicate. Slight grain dislodgement was displayed on worn 5Y-ZP surfaces, while more apparent grain dislodgement and wear grooves were found on lithium disilicate. Plastic deformation of worn palladium-silver alloy accumulated at the end of wear track. Cracks were detected in the human enamel specimens.
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Affiliation(s)
- Wissanee Jia-Mahasap
- Lecturer, Department of Prosthodontics, Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand
| | - Kuljirarnat Jitwirachot
- Graduate student, Department of Prosthodontics, Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand
| | - Julie A Holloway
- Professor Emeritus, Department of Prosthodontics, The University of Iowa, Iowa City, Iowa
| | - Wetchayan Rangsri
- Assistant Professor, Department of Mechanical Engineering, Faculty of Engineering, Chiang Mai University, Chiang Mai, Thailand
| | - Pimduen Rungsiyakull
- Assistant Professor, Department of Prosthodontics, Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand.
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An In Vitro Study to Evaluate the Effect of Artificial Aging on Translucency, Contrast Ratio, and Color of Zirconia Dental Ceramic at Different Sintering Levels. COATINGS 2022. [DOI: 10.3390/coatings12050642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Increasing demands for aesthetically pleasing dental restorations have promoted the use of materials that display superior optical properties. Zirconia-based all-ceramic systems have good optical properties, thus providing the desired esthetics for dental restorations. The altered oral conditions impact the physical properties of these materials. Multiple studies have been conducted to evaluate the effect of aging on the mechanical properties of computerized-aided design and computerized-aided manufacturing (CAD/CAM)-based zirconia; however, there is a scarcity of literature discussing the effect of aging on change in translucency, contrast ratio, and color. Therefore, this research aimed to evaluate the effect of accelerated artificial aging on translucency parameter (TP), contrast ratio (CR), and color of CAD/CAM zirconia at different sintering temperatures. Twenty-eight rectangular-shaped specimens were obtained by CAD/CAM milling of zirconia blank. Sintering of the samples was carried out at four different temperatures 1350 °C, 1400 °C, 1450 °C, and 1500 °C, respectively. Thermocycling of the samples was performed in a thermocycler. TP, CR, and color evaluation of all the samples was done again using a Spectrophotometer. Data acquired were statistically evaluated by one-way ANOVA and Post Hoc test. The highest amount of change in TP was recorded for specimens sintered at 1400 °C (1.86), whereas the least change was attributed to 1350 °C (0.51). The highest change in CR was observed in specimens sintered at 1500 °C (0.0971), and the least change in CR was observed at 1450 °C (0.0086). The highest ΔE values were recorded for 1400 °C against both white (1.86) and black background (2.17), whereas the least change was attributed to 1350 °C against white (0.86) and against a black background (1.41). The changes in TP were significant, but CR did not show any significant change. ΔE values for all the experimental groups were significant, but were below the clinically perceptible range. An increase in sintering temperature increased the translucency.
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The effect of aging on the wear performance of monolithic zirconia. Dent Mater 2022; 38:e136-e146. [DOI: 10.1016/j.dental.2022.04.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 03/06/2022] [Accepted: 04/01/2022] [Indexed: 11/24/2022]
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Aljomard YRM, Altunok EÇ, Kara HB. Enamel wear against monolithic zirconia restorations: A meta-analysis and systematic review of in vitro studies. J ESTHET RESTOR DENT 2022; 34:473-489. [PMID: 34623015 DOI: 10.1111/jerd.12823] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 07/02/2021] [Accepted: 09/14/2021] [Indexed: 12/01/2022]
Abstract
OBJECTIVE An assessment was performed to identify and evaluate dental enamel wear caused by monolithic zirconia restoration. Literature searches were conducted in PubMed, Science Direct, Cochrane Evidence, and the Cochrane Library up to May 2020. MATERIAL AND METHODS Studies were selected for systematic review according to the inclusion (articles conducted on the wear of enamel samples opposing monolithic zirconia) and exclusion (case reports, non-English articles, and monolithic zirconia samples facing other materials rather than human enamel) criteria. Of those, articles on polished and glazed monolithic zirconia subjected to a 50 N vertical load with a range of 240,000-250,000 cycles, equivalent to 1 year of in vivo mastication, were included in the meta-analysis. RESULTS In total, 3968 articles were pooled. Twenty-five articles met the inclusion criteria for the systematic review. Three studies were included in the meta-analysis. The results showed that the enamel wear against monolithic zirconia was within the statistically accepted level. Moreover, the polished monolithic zirconia surface caused less enamel wear than the glazed surface. CONCLUSION This review indicates that monolithic zirconia restorations cause acceptable antagonist enamel wear. Moreover, the meta-analysis results agreed that the final restoration's surface texture plays an essential role in the wear process. CLINICAL SIGNIFICANCE Monolithic zirconia restorations have been widely used in dental practice because they eliminate the chipping problems resulting from using veneered restorations. With recent technology development, monolithic zirconia has obtained more esthetic features and a more natural look. However, due to the high strength and surface roughness of monolithic zirconia, wear on the antagonist's teeth was detected. The results showed that this wear amount was statistically acceptable and lower than other ceramics such as feldspathic porcelain and enamel. Furthermore, surface treatment methods must be applied to minimize tooth wear, as polished or glazed surfaces interfere with enamel loss.
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Affiliation(s)
- Yasamin R M Aljomard
- Graduate School of Health Sciences, PhD programs, Prosthodontics Department, Istanbul Medipol University, Istanbul, Turkey
| | - Elif Çiğdem Altunok
- Department of Biostatistics and Medical Informatics, Faculty of Medicine, Yeditepe University, Istanbul, Turkey
| | - Haluk Barış Kara
- Department of Prosthodontics, School of Dentistry, Istanbul Medipol University, Istanbul, Turkey
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Wear Behavior of Different Generations of Zirconia: Present Literature. Int J Dent 2022; 2022:9341616. [PMID: 35295406 PMCID: PMC8920625 DOI: 10.1155/2022/9341616] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 01/16/2022] [Accepted: 02/10/2022] [Indexed: 12/22/2022] Open
Abstract
Objective. The wear behavior of the novel zirconia generation is less well understood and may be affected by compositional modifications compared to the conventional zirconia. Materials and Methods. Combinations of keywords such as “zirconia,” “high translucent,” and “wear” were searched in PubMed and Google Scholar databases up to May 2021. The total of 23 relevant articles was selected according to inclusion criteria. Results. Reports show comparable wear resistance of translucent zirconia to the conventional zirconia despite an increased cubic phase content and lower mean flexural strength. A meticulously polished surface creates the lowest surface roughness, producing favorable zirconia wear resistance and antagonist wear compared to a glazed surface. In comparison to other ceramic materials, zirconia produces the least wear on an enamel antagonist and almost undetectable wear when opposed by zirconia. Wear when paired against resin materials yields a favorable outcome, whereas wear behavior against a metal antagonist varies with the surface hardness of the metal. Conclusions. All zirconia generations are considered wear-friendly to all types of antagonists. Nonetheless, comparative studies on antagonist wear opposing zirconia of different compositions are still limited and further investigation is required.
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Yılmaz Savaş T, Akın C. Effects of sintering protocol and dipping time on the optical properties of monolithic zirconia. J Prosthet Dent 2022; 127:801.e1-801.e8. [DOI: 10.1016/j.prosdent.2021.12.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 12/02/2021] [Accepted: 12/02/2021] [Indexed: 10/19/2022]
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Al-Surkhi O, Hamad Z. Influence of firing temperature and duration on the hardness of dental zirconia for optimum selection of sintering conditions. J Appl Biomater Funct Mater 2022; 20:22808000221114218. [PMID: 35876066 DOI: 10.1177/22808000221114218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
OBJECTIVE In order to optimize the properties of dental zirconia, the sintering process involves firing zirconia to elevated temperatures for an extended time that can take several hours. The aim of this study is to investigate the effect of firing temperature and firing duration on the hardness of dental zirconia to indicate the optimum sintering conditions. METHODS Thirty-six zirconia specimens in shape of bars were randomly assigned to nine groups. The zirconia specimen groups were sintered using a sintering furnace with different firing temperatures (900°C, 1200°C, and 1800°C) and firing durations (6, 9, and 12 h). A total of 108 hardness measurements were conducted for all specimens (12 hardness readings per group). For each of the specimen groups, micro Vickers hardness test was performed using a load of 1 Kgf (9.807 N) and the Vickers hardness number was computed. Statistical analysis using Kruskal-Wallis test was conducted to examine the significant differences on Vickers hardness number HV among the specimen groups according to the firing parameters with 0.005 p-value used as an indicator. RESULTS Results suggest that there is an association between the increase in the hardness number and the increase in firing duration at a given firing temperature. The results also indicate that there is an association between the increase in the hardness number and increase in firing temperature at a given firing duration. CONCLUSIONS The greatest rate of hardness increase with time is associated with groups of firing temperature 1200°C. The highest rate of hardness increase with temperature happened during the first 6 h of sintering process. On the other hand, there is no significant increase in the hardness number when increasing the firing temperature beyond 1200°C.
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Affiliation(s)
- Omar Al-Surkhi
- Faculty of Engineering, Al-Quds University, Jerusalem, Palestine
| | - Zeina Hamad
- Faculty of Engineering, Al-Quds University, Jerusalem, Palestine
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Ghaffari T, Rad F, Goftari A, Pashazadeh F, Ataei K. Natural teeth wear opposite to glazed and polished ceramic crowns: A systematic review. Dent Res J (Isfahan) 2022. [DOI: 10.4103/1735-3327.363567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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Surface and bulk properties of zirconia as a function of composition and aging. J Mech Behav Biomed Mater 2021; 126:104994. [PMID: 34864575 DOI: 10.1016/j.jmbbm.2021.104994] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/18/2021] [Accepted: 11/21/2021] [Indexed: 01/08/2023]
Abstract
Yttria-stabilized zirconia (Y-SZ) materials with different levels of translucency have been used for indirect dental restorations. Y-SZ composition and microstructure are modified to improve translucency, and it is not clear how these materials respond to aging. This study evaluated the effect of hydrothermal aging (HA) performed in an autoclave on the properties of four dental Y-SZ materials with different compositions. Sintered bar-shaped specimens (14 x 4 x 2 mm) were prepared from four different zirconia-based materials (n = 40): low translucency 3 mol % Y-SZ (3Y-LT; Ceramill ZI, Amann Girrbach); high translucency 4 mol % Y-SZ (4Y-HT; Ceramill Zolid); and two high translucency 5 mol % Y-SZ (5Y-HT - Lava Esthetic, 3M; 5Y-SHT - Ceramill Zolid FX). Fully sintered specimens were exposed to HA for different times (control - 0 h, 5 h, 10 h, or 15 h at 134 °C, 2 bar pressure) and characterized for surface roughness, flexural strength (three-point bending), hardness and elastic modulus (nanoindentation), surface wettability (sessile drop technique) and crystalline content (x-ray diffraction, XRD). Data was analyzed by two-way ANOVA and Tukey HSD (p < 0.05). Zirconia composition significantly affected roughness (p = 0.016). Zirconia*aging interaction affected flexural strength (p = 0.012), surface wettability (p < 0.001), and hardness (p = 0.002). Zirconia composition (p = 0.011) and aging (p = 0.001) affected elastic modulus, while the interaction effect was not significant (p = 0.94). HA affects zirconia-based materials in different degrees. For 3Y-LT and 4Y-HT, surface and bulk properties were affected by aging to a similar extent. However, surface and bulk properties may change during clinical use as a result of prolonged degradation of Y-SZ.
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The Effect of Translucency and Surface Treatment on the Flexural Strength of Aged Monolithic Zirconia. Int J Dent 2021; 2021:8022430. [PMID: 34795763 PMCID: PMC8594981 DOI: 10.1155/2021/8022430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 10/06/2021] [Accepted: 10/28/2021] [Indexed: 11/17/2022] Open
Abstract
Aims This in vitro study aimed to evaluate the effect of the degrees of translucency in different types of monolithic zirconia as well as the aging and surface treatment with airborne particle abrasion on the flexural strength of monolithic zirconia. Materials and Methods Sixty bar-shaped specimens were fabricated from three different types of presintered monolithic zirconia (n = 20 per group) including low translucent (LT) (DD Bio ZW iso, high strength zirconia, Dental Direkt, Germany), high translucent (HT) (DD Bio ZX2 98, high translucent zirconia, Dental Direkt, Germany), and multilayered system (ML) (DD cubeX2®ML, multilayer, cubic zirconia system, Dental Direkt, Germany). Each monolithic zirconia group was equally subdivided according to be either air-abraded with 110 µm aluminium oxide particles or left untreated (control). After thermocycling, the flexural strength was measured by using a universal testing machine. Two-way ANOVA followed by Tukey's post hoc and independent samples t-test were used for the statistical analyses (P < 0.05). Results Surface treatment and types of zirconia were found to have a significant interaction (P = 0.010). Having controlled the effect of surface treatment, the flexural strength of HT and LT zirconia was found to be significantly higher than the ML zirconia system (P ≤ 0.001). Airborne particle abrasion could significantly decrease the flexural strength of monolithic zirconia only in ML zirconia (P = 0.002). Conclusions Multilayered zirconia system had the lowest flexural strength among all groups. Moreover, the flexural strength of this system was attenuated by surface treatment with airborne particles abrasion.
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Singh RG, Li KC, Lyons KM, Waddell JN. Effect of Two Brands of Glaze Material on the Flexural Strength and Probability of Failure of High Translucent Monolithic Zirconia. MATERIALS 2021; 14:ma14227022. [PMID: 34832419 PMCID: PMC8623283 DOI: 10.3390/ma14227022] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 11/09/2021] [Accepted: 11/17/2021] [Indexed: 11/25/2022]
Abstract
(1) Background: The effect of glazing on the mechanical properties of monolithic high translucent zirconia is not well reported. Therefore, the purpose of this study was to evaluate the effect of glazing on the flexural strength of high translucent zirconia; (2) Methods: Ninety specimens were prepared from second-generation 3Y-TZP high translucent blocks and divided into three groups. Glaze materials were applied on one surface of the specimen and subjected to a four-point bending test and flexural stress and flexural displacement values were derived. Descriptive fractographic analysis of surfaces was conducted to observe the point of failure and fracture pattern.; (3) Results: Control-nonglazed (647.17, 1σ = 74.71 MPa) presented higher flexural strength values compared to glaze I (541.20, 1σ = 82.91 MPa) and glaze II (581.10, 1σ = 59.41 MPa). Characteristic strength (σƟ) from Weibull analysis also observed higher (660.67 MPa) values for the control specimens. Confocal microscopy revealed that glazed surfaces were much rougher than control surfaces. Descriptive fractographic analysis revealed that there was no correlation between the point of failure initiation and flexural strength; (4) Conclusions: The test results demonstrated that glazing significantly decreased the flexural strength and flexural displacement of the zirconia specimens.
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Effect of Water Storage on Hardness and Interfacial Strength of Resin Composite Luting Agents Bonded to Surface-Treated Monolithic Zirconia. Dent J (Basel) 2021; 9:dj9070078. [PMID: 34356194 PMCID: PMC8307623 DOI: 10.3390/dj9070078] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Revised: 07/01/2021] [Accepted: 07/02/2021] [Indexed: 11/24/2022] Open
Abstract
Background: Durable bonding between resin composite luting agents (CLA) and zirconia is still a matter of controversy. The purpose of this study was to evaluate the effect of water storage on hardness and interfacial strength of three CLA, a non-adhesive (Multilink Automix/ML), an adhesive (Panavia F 2.0/PF) and a self-adhesive (PermaCem 2.0/PC), bonded to polished (CL) and grit-blasted (AL: 50 μm alumina, SJ: Sil-Jet + Monobond Plus silane) monolithic zirconia surfaces. Methods: CLA specimens (n = 5/cement, condition) were prepared, stored under dry conditions or immersed in water, and Vickers hardness (VH) measurements were obtained at 1 h, 24 h, 1 week and 3 weeks intervals. Optical profilometry was used to determine the roughness parameters (Sa, Sz, Sdr, Sci) of zirconia surfaces (n = 5/treatment). A shear strength test (SBS, n = 10 × 2/cement) was performed to assess the strength and fractography of the cements bonded to zirconia after isothermal water storage and thermal-cycling (TC). Results: PF demonstrated significantly lower VHN after water storage at all time intervals, PC at 1 w, 3 w and ML at 3 w. SJ and AL showed significantly higher values from CL in all roughness parameters. Weibull analysis revealed the following significance in σο ranking within the same material: AL, SJ, ALTC > SJTC, CL > CLTC (PF); SJ, SJTC, AL, ALTC > CL, CLTC (PC) and SJ, SJTC > AL > ALTC > CL, CLTC (ML). Within the same surface treatment subgroups, the significance in σo ranking was PC, ML > PF (before/after TC) for SJ; PC > PF > ML (before TC), PC, PF > ML (after TC) for AL, and PC > PF > ML (before/after TC) for CL. For the m ranking, the only significant difference within each material group was found in PC (AL > ALTC) and for the same surface treatment in AL (PC > ML). Conclusion: There are significant differences in the water plasticization susceptibility of the CLA tested; the materials with adhesive monomers were the most affected. Tribo-chemical silica coating combined with a silane coupling agent was the most efficient bonding treatment for the non-adhesive and the self-adhesive materials. The adhesive CLA performed better on alumina-blasted than on tribo-chemically coated surfaces.
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Solá-Ruíz MF, Rico-Coderch A, Montiel-Company JM, Fons-Badal C, Verdejo-Solá B, Agustín-Panadero R. Influence of the chemical composition of monolithic zirconia on its optical and mechanical properties. Systematic review and meta-regression. J Prosthodont Res 2021; 66:193-207. [PMID: 34176849 DOI: 10.2186/jpr.jpr_d_20_00218] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
PURPOSE This systematic review set out to investigate the influence of chemical composition and specimen thickness of monolithic zirconia on its optical and mechanical properties. Meta-analysis and meta-regression analyzed the effects of variations in percentages of yttrium, aluminum, and specimen thickness of monolithic zirconia. STUDY SELECTION The review followed recommendations put forward in the PRISMA checklist. An electronic search for relevant articles published up to October 2019 was conducted in the Pubmed, Cochrane, Scopus, Scielo, and Web of Science databases, with no language limits and articles published in the last 10 years. From 167 relevant articles; applying inclusion criteria based on the review's PICO question, 26 articles were selected for qualitative synthesis (systematic review) and 24 for quantitative synthesis (meta-analysis). Experimental in vitro studies published were selected and their quality was assessed using the modified Consort scale for in vitro studies of dental materials. RESULTS The variables yttrium, aluminum and thickness were analyzed in random effects models, observing high heterogeneity ( > 75%), and finding statistically significant influences on the properties of monolithic zirconia (p<0.05). CONCLUSIONS Within the review's limitations, it may be concluded that variations in the percentage of yttrium and aluminum influence the optical and mechanical properties of monolithic zirconia, making it more or less esthetic and resistant in relation to each variable. The clinical implications of these findings can help select the most appropriate type of zirconia to meet the different clinical needs when restoring different regions (posterior or anterior).
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Affiliation(s)
| | - Aitana Rico-Coderch
- Department of Stomatology, Faculty of Medicine and Dentistry, University of Valencia, Valencia
| | | | - Carla Fons-Badal
- Department of Stomatology, Faculty of Medicine and Dentistry, University of Valencia, Valencia
| | - Blanca Verdejo-Solá
- Department of Medicine, Faculty of Medicine and Dentistry, Universidad Cardenal Herrera-CEU, Valencia
| | - Rubén Agustín-Panadero
- Department of Stomatology, Faculty of Medicine and Dentistry, University of Valencia, Valencia
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Grambow J, Wille S, Kern M. Impact of changes in sintering temperatures on characteristics of 4YSZ and 5YSZ. J Mech Behav Biomed Mater 2021; 120:104586. [PMID: 34044252 DOI: 10.1016/j.jmbbm.2021.104586] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 04/30/2021] [Accepted: 05/09/2021] [Indexed: 11/29/2022]
Abstract
OBJECTIVES The aim of this study was to evaluate the effect of different sintering temperatures on biaxial flexural strength (BFS), dynamic loading, surface hardness, color reproduction, translucency, surface roughness and microstructure of zirconia with 4 mol% yttria (4YSZ) compared to zirconia with 5 mol% yttria (5YSZ). METHODS Zirconia discs with 12 mm diameter and 1.2 mm thickness were prepared and divided into three groups (n = 53) according to different sintering temperatures (1400 °C, 1500 °C and 1600 °C). Each group was divided into five subgroups (n = 10) according to the dynamic loading procedure (none, 50%, 65%, 75% and 80%) conducted before the quasi-static BFS test and another subgroup (n = 3) used for X-ray-diffraction (XRD) microstructure analysis. BFS test and dynamic loading were performed with a piston-on-three-ball test. The surface hardness was evaluated according to Vickers. Color reproduction and translucency were measured with a spectrophotometer. A 3D laser scanning microscope was used to determine the surface roughness. Grain size measurements were performed using SEM. RESULTS A significant increase in biaxial flexural strength was observed while the sintering temperature decreased. 4YSZ had significantly higher results in biaxial flexural strength than 5YSZ. A decrease in sintering temperature resulted in a significant increase in Vickers hardness. Furthermore, 4YSZ showed significantly better color reproduction with increasing sintering temperature. At higher temperatures (1500 °C and 1600 °C), 4YSZ showed better color reproduction than 5YSZ. Compared to 4YSZ, specimens of 5YSZ exhibited significant higher translucency. Using XRD, a distorted tetragonal phase was detected in addition to regular tetragonal and cubic phases in specimens without any stress and at a low sintering temperature. The grain sizes of both materials increased with an increase in sintering temperature. CONCLUSION The sintering temperature has significant effects on the microstructure and thus on the mechanical and optical properties of the evaluated zirconia.
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Affiliation(s)
- Julia Grambow
- Department of Prosthodontics, Propaedeutics and Dental Materials, School of Dentistry, Christian-Albrechts University, Arnold-Heller-Straße 16, Kiel, D-24105, Germany.
| | - Sebastian Wille
- Department of Prosthodontics, Propaedeutics and Dental Materials, School of Dentistry, Christian-Albrechts University, Arnold-Heller-Straße 16, Kiel, D-24105, Germany.
| | - Matthias Kern
- Department of Prosthodontics, Propaedeutics and Dental Materials, School of Dentistry, Christian-Albrechts University, Arnold-Heller-Straße 16, Kiel, D-24105, Germany.
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Kilinc H, Sanal FA. Effect of sintering and aging processes on the mechanical and optical properties of translucent zirconia. J Prosthet Dent 2021; 126:129.e1-129.e7. [PMID: 33965239 DOI: 10.1016/j.prosdent.2021.03.024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 03/24/2021] [Accepted: 03/24/2021] [Indexed: 02/04/2023]
Abstract
STATEMENT OF PROBLEM Sintering holding times and aging conditions may affect the optical, mechanical, and structural properties of polychromatic multitranslucent zirconia. However, a consensus on the ideal sintering condition for this material is lacking. PURPOSE The purpose of this in vitro study was to investigate the effect of different sintering holding and autoclave aging times on the flexural strength (FS), grain size, and translucency parameter (TP00) of a translucent zirconia. MATERIAL AND METHODS Sixty bar-shaped and 60 rectangular-shaped specimens were prepared from computer-aided design and computer-aided manufacturing (CAD-CAM) zirconia blocks and split into 2 groups to be sintered at 1550 °C for different holding times (regular: 2 hours, prolonged: 5 hours). The specimens were then divided into 3 subgroups and subjected to aging processes (control, aging for 60 minutes, aging for 120 minutes). FS values were obtained by using a 3-point bend test and Weibull analysis was conducted. Grain size evaluations were performed by using scanning electron microscope (SEM) observations. TP00 was measured with a spectrophotometer. Statistical evaluation included the Kolmogorov-Smirnov, 2-way ANOVA, and Tukey HSD tests (α=.05). RESULTS The sintering procedure, aging, and their interaction significantly influenced the TP00 (P<.05). FS values and grain sizes were affected by aging only (P<.001). Both aging times resulted in reduced FS and increased grain sizes. Prolonged sintering in combination with 120 minutes of aging negatively affect the TP00 scores (P<.05). CONCLUSIONS FS values were similar under regular and prolonged sintering. Prolonged sintering led to a decrease in translucency after 120 minutes of aging. Steam autoclave aging can affect the optical and mechanical properties of translucent zirconia.
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Affiliation(s)
- Hamiyet Kilinc
- Associate Professor, Department of Prosthodontics, Faculty of Dentistry, Bolu Abant Izzet Baysal University, Bolu, Turkey.
| | - Fatma A Sanal
- Associate Professor, Department of Prosthodontics, Faculty of Dentistry, Bolu Abant Izzet Baysal University, Bolu, Turkey
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Fathy SM, Al-Zordk W, E Grawish M, V Swain M. Flexural strength and translucency characterization of aesthetic monolithic zirconia and relevance to clinical indications: A systematic review. Dent Mater 2021; 37:711-730. [PMID: 33581910 DOI: 10.1016/j.dental.2021.01.022] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 11/15/2020] [Accepted: 01/20/2021] [Indexed: 02/04/2023]
Affiliation(s)
- Salma M Fathy
- Dental Biomaterials Department, Faculty of Oral and Dental Medicine, Zagazig University, Zagazig, Egypt.
| | - Walid Al-Zordk
- Fixed Prosthodontics Department, Faculty of Dentistry, Mansoura University, Mansoura, Egypt
| | - Mohammed E Grawish
- Oral Biology Department, Faculty of Dentistry, Mansoura University, Mansoura, Egypt
| | - Micheal V Swain
- Discipline of Biomaterials, Faculty of Dentistry, University of Sydney, Australia
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The influence of zirconia veneer thickness on the degree of conversion of resin-matrix cements: an integrative review. Clin Oral Investig 2021; 25:3395-3408. [PMID: 33783593 DOI: 10.1007/s00784-021-03904-w] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 03/19/2021] [Indexed: 10/21/2022]
Abstract
OBJECTIVE The main aim of this study was to conduct an integrative review on the influence of the zirconia veneer thickness on the degree of conversion of resin-matrix cements. MATERIALS AND METHOD An electronic search was performed on PubMed using a combination of the following search items: zirconia, thickness, veneer, degree of conversion, resin cement, light curing, and polymerization. Articles published in the English language, up to July 2020, were included regarding the influence of ceramic veneer thickness on the degree of conversion of resin-matrix cements. Randomized controlled trials and prospective cohort studies were also evaluated. RESULTS Of the 21 selected studies, 9 investigated the light-curing effect, while five other articles evaluated the ceramic translucency. Three studies evaluated the degree of conversion of the resin-matrix cement while four articles assessed the veneer thickness. Results revealed a significant decrease of light transmission through the zirconia with a thickness ranging from 0.1 up to 1.5 mm. However, the ultra-thin thickness around 0.1 and 0.3 mm allowed a full polymerization of the dual-curing resin-matrix cement resulting in the integrity of the interface properties. The light-curing process of resin-matrix cements is also affected by the shade, chemical composition, and microstructure of zirconia and resin cement. Optimal conditions of light-curing are required to reach the threshold intensity of light and energy for polymerization of resin-matrix cements. CONCLUSIONS The increase in zirconia veneer thickness negatively affects the degree of conversion of resin-matrix cements. Also, shade and microstructure are key factor to improve the light curing of resin cements. CLINICAL RELEVANCE Clinicians should consider the zirconia thickness on resin-based cementation since a higher veneer thickness can negatively affect the light irradiation intensity towards the dual-curing resin-matrix cement. Thus, the degree of conversion of the resin-matrix cement can decrease leading to a low chemical stability (e.g., color instability) and poor mechanical properties.
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Effect of sintering process on microstructure, 4-point flexural strength, and grain size of yttria-stabilized tetragonal zirconia polycrystal for use in monolithic dental restorations. J Prosthet Dent 2021; 125:824.e1-824.e8. [PMID: 33775390 DOI: 10.1016/j.prosdent.2021.01.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 01/27/2021] [Accepted: 01/27/2021] [Indexed: 11/22/2022]
Abstract
STATEMENT OF PROBLEM Modifications have been made in the microstructure and sintering parameters of monolithic zirconia to improve esthetics qualities and avoid chipping of 2-layer restorations. However, how these modifications affect the physical and mechanical properties of zirconia is unclear. PURPOSE The purpose of this in vitro study was to compare the influence of different sintering parameters on the microstructure, 4-point flexural strength, density, and grain size of 2 commercially available zirconia advocated for the fabrication of monolithic dental prostheses and 1 commercially available zirconia for use as a core material. MATERIAL AND METHODS Three presintered blocks (Ceramill Zolid, Prettau, and IPS e.max ZirCAD) were used. Specimens were cut and sintered as per the manufacturer's recommendation or as per a modified heating protocol. Ceramill Zolid (Z1450) was sintered at 1450 °C, Prettau (P1600) was sintered at 1600 °C, and IPS e.max ZirCAD (I1530) was sintered at 1530 °C by following the manufacturer's heating protocol. Groups Ceramill Zolid Z1530 and Z1600 were sintered at temperatures higher than the manufacturer's recommendation. Specimens from each group (n=13) were analyzed with X-ray diffraction (XRD), density calculus, average grain size measurement, and 4-point flexural tests. Data were compared by using ANOVA (α=.05). RESULTS XRD analysis showed the presence of a tetragonal metastable phase in all groups before and after sintering. No significant differences were found in relative density values for the 3 Ceramill groups (5.98 g/cm3). Groups I1530 (6.03 g/cm3) and P1600 (6.03 g/cm3) had similar density results greater than 6.00 g/cm3. The average grain size of all groups remained lower than 1 μm. P1600 had the highest grain size (0.817 μm), and Z1450 presented the lowest grain size (0.465 μm). P1600 showed the most homogeneous flexural strength and the highest Weibull modulus (m=8.22). Z1530 presented the lowest Weibull modulus (m=4.58). IPS e.max ZirCAD (I1530) had the highest flexural strength (1057.41 ±150.54 MPa), and Ceramill Zolid Z1450 had the lowest (621.01 ±138.08 MPa). CONCLUSIONS The flexural strength, microstructure, crystal phase, and grain size of the analyzed zirconia varied as per the sintering processing. The IPS e.max ZirCAD had the highest flexural strength (1057.41 ±150.54 MPa), followed by Prettau zirconia (864.18 ±118.21), with a statistically significant difference (P<.05). The Ceramill Zolid zirconia presented the lowest flexural strength, as well as the lowest reliability for all sintering parameters used (Z1450: 621.01 ±138.08 MPa and m=5.42; Z1530: 713.10 ±175.44 MPa and m=4.58; Z1600: 630.15 ±112.08 MPa and m=6.87). At a lower heating rate (8 °C/min), the final density increased and excessive grain growth in group Z1530 was prevented.
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Hjerppe J, Rodas S, Korvala J, Pesonen P, Kaisanlahti A, Özcan M, Suojanen J, Reunanen J. Surface Roughness and Streptococcus mutans Adhesion on Metallic and Ceramic Fixed Prosthodontic Materials after Scaling. MATERIALS 2021; 14:ma14041027. [PMID: 33671563 PMCID: PMC7926524 DOI: 10.3390/ma14041027] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 02/12/2021] [Accepted: 02/13/2021] [Indexed: 12/12/2022]
Abstract
The aim of this study was to evaluate the surface roughness of fixed prosthodontic materials after polishing or roughening with a stainless steel curette or ultrasonic scaler and to examine the effect of these on Streptococcus mutans adhesion and biofilm accumulation. Thirty specimens (10 × 10 × 3 mm3) of zirconia (Zr), pressed lithium disilicate (LDS-Press), milled lithium disilicate glazed (LDS-Glaze), titanium grade V (Ti) and cobalt-chromium (CoCr) were divided into three groups (n = 10) according to surface treatment: polished (C), roughened with stainless steel curette (SC), roughened with ultrasonic scaler (US). Surface roughness values (Sa, Sq) were measured with a spinning disc confocal microscope, and contact angles and surface free energy (SFE) were measured with a contact angle meter. The specimens were covered with sterilized human saliva and immersed into Streptococcus mutans suspensions for bacterial adhesion. The biofilm was allowed to form for 24 h. Sa values were in the range of 0.008–0.139 µm depending on the material and surface treatment. Curette and ultrasonic scaling increased the surface roughness in LDS-Glaze (p < 0.05), Ti (p < 0.01) and CoCr (p < 0.001), however, surface roughness did not affect bacterial adhesion. Zr C and US had a higher bacterial adhesion percentage compared to LDS-Glaze C and US (p = 0.03). There were no differences between study materials in terms of biofilm accumulation.
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Affiliation(s)
- Jenni Hjerppe
- Clinic of Reconstructive Dentistry, Center of Dental Medicine, University of Zürich, 8032 Zürich, Switzerland
- Correspondence: ; Tel.:+ 41-44-634-0404
| | - Sampo Rodas
- Biocenter Oulu & Cancer and Translational Medicine Research Unit, University of Oulu, 90014 Oulu, Finland; (S.R.); (J.K.); (A.K.); (J.R.)
| | - Johanna Korvala
- Biocenter Oulu & Cancer and Translational Medicine Research Unit, University of Oulu, 90014 Oulu, Finland; (S.R.); (J.K.); (A.K.); (J.R.)
| | - Paula Pesonen
- Infrastructure for Population Studies, Faculty of Medicine, University of Oulu, 90014 Oulu, Finland;
| | - Anna Kaisanlahti
- Biocenter Oulu & Cancer and Translational Medicine Research Unit, University of Oulu, 90014 Oulu, Finland; (S.R.); (J.K.); (A.K.); (J.R.)
| | - Mutlu Özcan
- Center of Dental Medicine, Division of Dental Biomaterials, Clinic for Reconstructive Dentistry, University of Zürich, 8032 Zürich, Switzerland;
| | - Juho Suojanen
- Päijät-Häme Joint Authority for Health and Wellbeing, Department of Oral and Maxillo-facial Surgery, 15850 Lahti, Finland;
- Cleft Palate and Craniofacial Centre, Department of Plastic Surgery, Helsinki University Hospital, 00029 Helsinki, Finland
| | - Justus Reunanen
- Biocenter Oulu & Cancer and Translational Medicine Research Unit, University of Oulu, 90014 Oulu, Finland; (S.R.); (J.K.); (A.K.); (J.R.)
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Meng M, Li X, Li D, Guo Z, Li K, Guo J, He L, Zhang S. Improved reliability of wear performance for a fluorapatite veneering porcelain by ion-exchange strengthening and toughening. J Mech Behav Biomed Mater 2020; 112:103986. [DOI: 10.1016/j.jmbbm.2020.103986] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Revised: 07/09/2020] [Accepted: 07/11/2020] [Indexed: 10/23/2022]
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Dal Piva AMDO, Tribst JPM, Benalcázar Jalkh EB, Anami LC, Bonfante EA, Bottino MA. Minimal tooth preparation for posterior monolithic ceramic crowns: Effect on the mechanical behavior, reliability and translucency. Dent Mater 2020; 37:e140-e150. [PMID: 33246664 DOI: 10.1016/j.dental.2020.11.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 08/10/2020] [Accepted: 11/02/2020] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Despite the increased use of monolithic crowns, their performance has yet to be determined when the minimal tooth preparation (MTP) principle is considered. The goal of this study was to evaluate the effect of MTP on the mechanical behavior, reliability and translucency of posterior monolithic ceramic crowns. METHODS Dentin analogues were machined using two preparation designs (0.5 or 1 mm reduction) to receive first molar crowns in order to evaluate the monolithic crown performance. Next, 126 crowns were divided (21/g) according to the material (High translucent zirconia - YZHT, Zirconia reinforced lithium silicate - ZLS and Hybrid ceramic - HC) and thickness (0.5 or 1 mm). Tensile stress concentration was calculated using the finite element method. The crowns were adhesivelly cemented and step stress fatigued to calculate reliability for missions at 600 and 1000 N. Translucency was analyzed in 10 discs of each material and thickness. RESULTS Higher stress concentration was found in thinner crowns and those with higher elastic modulus. YZHT crowns were suspended when fatigue reached 1500 N load, thus 1-parameter Weibull was used to analyze the data. Reliability was only affected by thickness at 1000 N. ZLS.5 showed lower survival than HC.5, which was similar to the groups that presented 100% survival. YZHT showed the highest strength and data scattering. ZLS1 (22.3 ± 1.4) presented higher translucency than HC1 (19.2 ± 0.6) and YZHT1 (12.0 ± 2.9), whereas ZLS.5 and HC.5 were similar to each other (26.5 ± 2.3, 26.7 ± 2.2) and superior to YZHT.5 (12.7 ± 1.2). SIGNIFICANCE HC.5 combined high reliability and translucency with low stress concentration, yielding better crown performance and tooth preservation.
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Affiliation(s)
- Amanda Maria de Oliveira Dal Piva
- PhD Graduate Program in Restorative Dentistry, São Paulo State University (Unesp), Institute of Science and Technology, Av. Eng. Francisco José Longo, nº 777, Jardim São Dimas, 12245-000 São José dos Campos, SP, Brazil.
| | - João Paulo Mendes Tribst
- PhD Graduate Program in Restorative Dentistry, São Paulo State University (Unesp), Institute of Science and Technology, Av. Eng. Francisco José Longo, nº 777, Jardim São Dimas, 12245-000 São José dos Campos, SP, Brazil.
| | - Ernesto Byron Benalcázar Jalkh
- Department of Prosthodontics and Periodontology, University of São Paulo - Bauru School of Dentistry. Alameda Dr. Octávio Pinheiro Brisolla, 9-75, 17012-901, Bauru, SP, Brazil.
| | - Lilian Costa Anami
- PhD Graduate Program in Restorative Dentistry, São Paulo State University (Unesp), Institute of Science and Technology, Av. Eng. Francisco José Longo, nº 777, Jardim São Dimas, 12245-000 São José dos Campos, SP, Brazil.
| | - Estevam Augusto Bonfante
- Department of Prosthodontics and Periodontology, University of São Paulo - Bauru School of Dentistry. Alameda Dr. Octávio Pinheiro Brisolla, 9-75, 17012-901, Bauru, SP, Brazil.
| | - Marco Antonio Bottino
- PhD Graduate Program in Restorative Dentistry, São Paulo State University (Unesp), Institute of Science and Technology, Av. Eng. Francisco José Longo, nº 777, Jardim São Dimas, 12245-000 São José dos Campos, SP, Brazil.
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Tekin YH, Hayran Y. Fracture resistance and marginal fit of the zirconia crowns with varied occlusal thickness. J Adv Prosthodont 2020; 12:283-290. [PMID: 33149849 PMCID: PMC7604235 DOI: 10.4047/jap.2020.12.5.283] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 06/26/2020] [Accepted: 08/13/2020] [Indexed: 11/08/2022] Open
Abstract
PURPOSE The present study aimed to evaluate the clinical applicability of monolithic zirconia (MZ) crowns of different thickness via determination of fracture resistance and marginal fit. MATERIALS AND METHODS MZ crowns with 0.5, 0.8, 1.0, and 1.5 mm thickness and porcelain fused to metal (PFM) crowns were prepared, ten crowns in each group. Marginal gaps of the crowns were measured. All crowns were aged with thermal cycling (5 - 55℃/10000 cycle) and chewing simulator (50 N/1 Hz/lateral movement: 2 mm, mouth opening: 2 mm/240000 cycles). After aging, fracture resistance of crowns was determined. Statistical analysis was performed with one-way ANOVA and Tukey's HDS post hoc test. RESULTS Fracture loads were higher in the PFM and 1 mm MZ crowns compared to 0.5 mm and 0.8 mm crowns. 1.5 mm MZ crowns were not broken even with the highest force applied (10 kN). All marginal gap values were below 86 µm even in the PFM crowns, and PFM crowns had a higher marginal gap than the MZ crowns. CONCLUSION The monolithic zirconia exhibited high fracture resistance and good marginal fit even with the 0.5 mm thickness, which might be used with reduced occlusal thickness and be beneficial in challengingly narrow interocclusal space.
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Affiliation(s)
- Yadel Hazır Tekin
- Department of Prosthodontic Dentistry, Faculty of Dentistry, Tokat Gaziosmanpasa University, Tokat, Turkey
| | - Yeliz Hayran
- Department of Prosthodontic Dentistry, Faculty of Dentistry, Tokat Gaziosmanpasa University, Tokat, Turkey
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Okutan Y, Kandemir B, Gundogdu Y, Kilic HS, Yucel MT. Combined application of femtosecond laser and air-abrasion protocols to monolithic zirconia at different sintering stages: Effects on surface roughness and resin bond strength. J Biomed Mater Res B Appl Biomater 2020; 109:596-605. [PMID: 33073447 DOI: 10.1002/jbm.b.34741] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 09/18/2020] [Accepted: 09/30/2020] [Indexed: 11/06/2022]
Abstract
This study aimed to investigate the effects of femtosecond laser (Fs) and/or air-abrasion protocols on surface roughness (Ra) of zirconia and resin bond strength. Eighty zirconia samples were randomly divided into eight subgroups according to surface treatment protocols: Control (C), Air-abrasion before sintering (ABS), Air-abrasion after sintering (AAS), Air-abrasion before and after sintering (ABS + AAS), Fs laser before sintering (FBS), Fs laser before sintering + air-abrasion after sintering (FBS + AAS), Fs laser after sintering (FAS), and Fs laser after sintering + air-abrasion after sintering (FAS + AAS). Measurements of Ra values were obtained using a surface profilometer. Surface morphological properties were evaluated with scanning electron microscopy (SEM), and crystallographic changes were examined by X-Ray diffractometry (XRD). Self-adhesive resin cement was bonded to zirconia samples, and shear bond strength (SBS) tests were performed. The data were statistically analyzed by one-way ANOVA, followed by Tamhane tests. The control group displayed the lowest Ra and SBS values among all groups. The highest Ra and SBS values were found in the FBS and FBS + AAS groups. Air-abrasion applied before sintering significantly increased the Ra of specimens. FAS, FAS + AAS, and ABS + AAS groups exhibited higher SBS values than AAS and ABS (p < .05). Air-abrasion applied after Fs laser did not produce any significant change in the Ra and SBS compared to Fs laser alone (p > .05). Femtosecond laser application may be a promising method to enhance the surface roughness of zirconia and improve resin bond strength. Air-abrasion at pre- and post-sintered stages may also be a viable surface treatment option.
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Affiliation(s)
- Yener Okutan
- Faculty of Dentistry, Department of Prosthodontics, Aydın Adnan Menderes University, Aydın, Turkey
| | - Banucicek Kandemir
- Faculty of Dentistry, Department of Prosthodontics, Selcuk University, Konya, Turkey
| | - Yasemin Gundogdu
- Department of Electric and Energy, Selcuk University, Kadınhanı Faik İçil Vocational High School, Konya, Turkey
| | - Hamdi Sukur Kilic
- Faculty of Science, Department of Physics, Selcuk University, Konya, Turkey
| | - Munir Tolga Yucel
- Faculty of Dentistry, Department of Prosthodontics, Selcuk University, Konya, Turkey
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Wear behavior and microstructural characterization of translucent multilayer zirconia. Dent Mater 2020; 36:1407-1417. [PMID: 32958309 DOI: 10.1016/j.dental.2020.08.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Revised: 07/12/2020] [Accepted: 08/29/2020] [Indexed: 11/22/2022]
Abstract
OBJECTIVE To characterize the composition, microstructure and wear properties of a multilayer translucent zirconia relative to the conventional 3Y-TZP. METHODS Two types of ceramics were evaluated: a multilayer zirconia (MULTI, IPS e.max ZirCAD Multi, Ivoclar Vivadent) and a control 3Y-TZP (IPS e.max ZirCAD LT, Ivoclar Vivadent). Pre-sintered CAD-CAM blocks were cut, ground, sintered and polished to 1 μm finish. The phase fraction and grain size were measured using XRD and FE-SEM. For wear testing (n = 12), square-shaped specimens (16 × 16 × 1 mm) were adhesively bonded to a dentin analog. Sliding wear tests were performed using a spherical zirconia antagonist (r = 3.15 mm), with 30 N load at 1.5 Hz for 500,000 cycles in water. Optical and scanning electron microscopes and 3D laser scanner were used for quantitative wear analyses. Data were analyzed using Student's t-test (α = 0.05). RESULTS For MULTI, the enamel layer had the highest cubic content and the largest grain size, followed by the two transition layers, and the dentin layer. 3Y-TZP showed the smallest grain size and cubic content. A significant amount of wear was observed in both materials up to 50,000 cycles until it reached a plateau. MULTI showed higher volume loss and greater wear depth than 3Y-TZP (p < 0.01). The higher volume loss was associated with extensive lateral fracture, leading to material spalling from the surface of cubic-containing zirconias. SIGNIFICANCE The wear pattern in multi-layered zirconia was more severe than 3Y-TZP. Additionally, the different layers of the multi-layered zirconia had similar wear behavior.
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Abdulmajeed A, Sulaiman T, Abdulmajeed A, Bencharit S, Närhi T. Fracture Load of Different Zirconia Types: A Mastication Simulation Study. J Prosthodont 2020; 29:787-791. [PMID: 32840940 DOI: 10.1111/jopr.13242] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/16/2020] [Indexed: 11/26/2022] Open
Abstract
PURPOSE To assess the effect of yttria mol% concentration and material thickness on the biaxial fracture load (N) of zirconia with and without mastication simulation. MATERIALS AND METHODS Disk-shaped specimens (N = 120) of 3 mol% yttria-partially stabilized zirconia, 3Y-PSZ (Katana High Translucent, Kuraray Noritake), 4 mol% yttria-partially stabilized zirconia, 4Y-PSZ (Katana Super Translucent Multi Layered) and 5 mol% Yttria-partially stabilized zirconia, 5Y-PSZ (Katana Ultra Translucent Multi Layered) were prepared to thicknesses of 0.7 and 1.2 mm. For each thickness, the biaxial fracture load (N) was measured with and without mastication simulation with 1.2 million cycles at a 110-N load and simultaneous thermal cycling at 5°C to 55°C. The data were analyzed by three-way Analysis of Variance (α = 0.05) and Tukey-Kramer adjusted multiple comparison test. RESULTS Yttria mol% concentration and material thickness had a statistically significant effect on the mean biaxial fracture load (F = 388.16, p < 0.001 and F = 714.33, p < 0.001 respectively). The mean biaxial fracture load ranged from the highest to the lowest; 3Y-PSZ, 4Y-PSZ, and 5Y-PSZ (p = 0.012). The mean biaxial fracture load of the 1.2 mm thickness groups was significantly higher than 0.7 mm thickness at any given condition (p = 0.002). Not all specimens survived the mastication simulation protocol. Fifty percent of the 0.7-mm-thick 4Y-PSZ specimens, 70% of the 0.7-mm-thick 5Y-PSZ specimens and 20% of 1.2-mm-thick 5Y-PSZ specimens fractured during mastication simulation. Mastication simulation had no statistically significant effect on the biaxial fracture load (F = 1.24, p = 0.239) of the survived specimens. CONCLUSIONS Lowering yttria mol% concentration and increasing material thickness significantly increases the fracture load of zirconia. At 0.7 mm thickness, only 3Y-PSZ survived masticatory simulation. A minimum material thickness of 1.2 mm is required for 4Y-PSZ or 5Y-PSZ.
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Affiliation(s)
- Awab Abdulmajeed
- Department of Prosthetic Dentistry and Stomatognathic Physiology, Institute of Dentistry, University of Turku, Turku, Finland.,Department of General Practice, School of Dentistry, Virginia Commonwealth University, Richmond, VA
| | - Taiseer Sulaiman
- Division of Comprehensive Oral Health, Adams School of Dentistry, University of North Carolina, Chapel Hill, NC
| | - Aous Abdulmajeed
- Department of Prosthetic Dentistry and Stomatognathic Physiology, Institute of Dentistry, University of Turku, Turku, Finland.,Department of General Practice, School of Dentistry, Virginia Commonwealth University, Richmond, VA
| | - Sompop Bencharit
- Department of General Practice, School of Dentistry, Virginia Commonwealth University, Richmond, VA.,Department of Biomedical Engineering, College of Engineering, Virginia Commonwealth University, Richmond, VA
| | - Timo Närhi
- Department of Prosthetic Dentistry and Stomatognathic Physiology, Institute of Dentistry, University of Turku, Turku, Finland.,City of Turku, Welfare Division, Turku, Finland
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De Angelis F, D'Arcangelo C, Buonvivere M, Rondoni GD, Vadini M. Shear bond strength of glass ionomer and resin-based cements to different types of zirconia. J ESTHET RESTOR DENT 2020; 32:806-814. [PMID: 32810368 DOI: 10.1111/jerd.12638] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 06/21/2020] [Accepted: 07/26/2020] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To investigate the shear bond strength (SBS) of a glass ionomer (GI) cement, an 10-methacryloyloxy-decyl dihydrogen phosphate (MDP)-based adhesive resin cement (MDP-based AC), an MDP-based self-adhesive resin cement (MDP-based SAC), an MDP-free self-adhesive resin cement (MDP-free SAC), and a resin-modified GI (RMGI) cement to a 3 mol% yttria-stabilized (3Y-TZP) and a 5 mol% yttria partially stabilized zirconia (5Y-PSZ). MATERIALS AND METHODS Fifty blocks were produced using 3Y-TZP and 5Y-PSZ, assigned to subgroups based on the five cements investigated (n = 10) and luted to cylindrical specimens of the same substrate. Each specimen was loaded in a SBS apparatus to failure. Mean SBS (MPa) values and standard deviations were calculated. Data were analyzed using a two-way analysis of variance and Tukey tests (α = .05). Failed specimens were subjected to fractographic analysis. RESULTS MDP-based AC and MDP-based SAC cements displayed the highest SBS values with both the substrates; GI cement showed the lowest. RMGI and MDP-free SAC cements performed better with 3Y-TZP than with 5Y-PSZ. Fractographic analysis revealed only adhesive and mixed failures. CONCLUSIONS MDP-based AC and MDP-based SAC cements are suitable for both 3Y-TZP and 5Y-PSZ. MDP-free SAC and RMGI cements are adequate choices for 3Y-TZP, but seem less effective with 5Y-PSZ. CLINICAL SIGNIFICANCE MDP-based SACs appear to be as reliable as MDP-based ACs for both 3Y-TZP and 5Y-PSZ cementation. Specifically, for 5Y-PSZ cementation, resin-based MDP-free SACs do not seem to guarantee predictable results in terms of SBS.
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Affiliation(s)
- Francesco De Angelis
- Unit of Restorative Dentistry and Endodontics, Department of Medical, Oral and Biotechnological Science, "G. D'Annunzio" University of Chieti-Pescara, Via dei Vestini, 31, Chieti, Italy
| | - Camillo D'Arcangelo
- Unit of Restorative Dentistry and Endodontics, Department of Medical, Oral and Biotechnological Science, "G. D'Annunzio" University of Chieti-Pescara, Via dei Vestini, 31, Chieti, Italy
| | - Matteo Buonvivere
- Unit of Restorative Dentistry and Endodontics, Department of Medical, Oral and Biotechnological Science, "G. D'Annunzio" University of Chieti-Pescara, Via dei Vestini, 31, Chieti, Italy
| | | | - Mirco Vadini
- Unit of Restorative Dentistry and Endodontics, Department of Medical, Oral and Biotechnological Science, "G. D'Annunzio" University of Chieti-Pescara, Via dei Vestini, 31, Chieti, Italy
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Papageorgiou-Kyrana K, Fasoula M, Kontonasaki E. Translucency of Monolithic Zirconia after Hydrothermal Aging: A Review of In Vitro Studies. J Prosthodont 2020; 29:489-500. [PMID: 32275345 DOI: 10.1111/jopr.13174] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Revised: 04/03/2020] [Accepted: 04/03/2020] [Indexed: 11/28/2022] Open
Abstract
PURPOSE Recent modifications in composition, structure, and fabrication methods have led to monolithic zirconia ceramics of superior translucency. However, during aging, intrinsic microstructural features, such as grain boundaries and pores, may affect light scattering and consequently the translucency of zirconia. The aim of this study was to systematically review if hydrothermal aging affects the translucency of monolithic zirconia. MATERIALS AND METHODS An electronic search in Medline and Scopus was conducted to identify the effect of hydrothermal aging on the translucency of zirconia. The search was limited to English-language publications and in vitro studies. The following search terms were used alone or in combination: "monolithic zirconia," "full contour zirconia," "Y-TZP zirconia," "tetragonal zirconia," "cubic zirconia," "aging," "hydrothermal aging," "steam autoclave," "translucency," "translucency parameter," and "contrast ratio." From the titles found after searching the electronic databases, only 10 articles met the inclusion criteria and were included in this review. The translucency parameter or total transmittance was used to extract data from the studies. RESULTS Aging reduced the translucency of monolithic zirconia in most of the studies; however, the differences varied according to the brand tested and the microstructure and thickness of the specimens. The thinner specimens presented higher translucency alterations. Although in all studies a change in translucency was recorded, its mean values suggest that the differences are within the acceptability threshold in most cases, independent of the color system used to calculate translucent parameter, so they are clinically undetectable. For longer aging times, beyond the perspective clinical life of the restorations, the change in translucency is higher than the acceptability threshold. CONCLUSIONS There is a controversy regarding how aging affects the translucency of monolithic zirconia ceramics; however, this may not be clinically important, as in most cases, changes (either decrease or increase) in translucency were within the acceptability thresholds.
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Affiliation(s)
| | - Maria Fasoula
- Postgraduate Student, Department of Prosthodontics, School of Dentistry, Faculty of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Eleana Kontonasaki
- Associate Professor, Department of Prosthodontics, School of Dentistry, Faculty of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece
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Lümkemann N, Pfefferle R, Jerman E, Sener B, Stawarczyk B. Translucency, flexural strength, fracture toughness, fracture load of 3-unit FDPs, Martens hardness parameter and grain size of 3Y-TZP materials. Dent Mater 2020; 36:838-845. [PMID: 32370908 DOI: 10.1016/j.dental.2020.03.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 01/31/2020] [Accepted: 03/30/2020] [Indexed: 10/24/2022]
Abstract
OBJECTIVE This investigation tested pre-shaded 3Y-TZP materials on optical, mechanical and structural properties and calculated correlations between these properties. METHODS Seven A2-shaded 3Y-TZP zirconia materials were investigated on translucency (T) via UV-vis-spectrophotometer, fracture load of 3-unit FDPs (FL), biaxial flexural strength (FS), Chevron-Notch Beam (CNB), fracture toughness (KIC) and Martens parameter (hardness: HM and indentation modulus: EIT). FL, FS and KIC were measured in a universal testing machine. The grain size was evaluated by scanning electron microscopy (SEM). Data was analyzed using one-way ANOVA followed by post hoc Scheffé, Kruskal-Wallis-, Mann-Whitney-U- and Pearson-test (p<0.05). RESULTS For translucency, negative correlations were found with results of facture load (R=-0.444, p<0.001) and KIC (R=-0.503, p<0.001). While a positive correlation was found between translucency and flexural strength (R=0.238, p=0.019), between fracture load and EIT (R=0.227, p<0.029), between fracture load and KIC (R=0.362, p<0.001) as well as between fracture load and the grain size (R=0.598, p=0.007). While the grain size positively correlated with EIT (R=0.534, p=0.017) as well as EIT with HM (R=0.720, p<0.001). SIGNIFICANCE Despite of being based on the same raw material, tested zirconia materials significantly differed regarding optical, mechanical (except biaxial flexural strength and Martens hardness) and structural properties. Materials with highest optical properties were those with lowest mechanical properties (CER, COP).
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Affiliation(s)
- Nina Lümkemann
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestrasse 70, 80336 Munich, Germany
| | - Regina Pfefferle
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestrasse 70, 80336 Munich, Germany
| | - Eva Jerman
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestrasse 70, 80336 Munich, Germany
| | - Beatrice Sener
- Periodontics and Cardiology, Clinic for Preventive Dentistry, University of Zurich, Plattenstrasse 11, 8032 Zurich, Switzerland
| | - Bogna Stawarczyk
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestrasse 70, 80336 Munich, Germany.
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Alraheam IA, Donovan T, Boushell L, Cook R, Ritter AV, Sulaiman TA. Fracture load of two thicknesses of different zirconia types after fatiguing and thermocycling. J Prosthet Dent 2020; 123:635-640. [DOI: 10.1016/j.prosdent.2019.05.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 04/26/2019] [Accepted: 05/21/2019] [Indexed: 12/01/2022]
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Öztürk C, Can G. Effect of sintering parameters on the mechanical properties of monolithic zirconia. J Dent Res Dent Clin Dent Prospects 2020; 13:247-252. [PMID: 32190207 PMCID: PMC7072090 DOI: 10.15171/joddd.2019.038] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Background.
Zirconia restorations with high mechanical properties are the current treatment options for fixed restorations
with advantages of high biocompatibility and low pulp irritation. Although the effect of sintering time and temperature on the
optical and mechanical properties of zirconia core material were investigated, the effect of these parameters on the translucent
monolithic zirconia is still uncertain. This study aimed to evaluate the effect of the changes in sintering temperature and
holding time on the mechanical and structural properties of monolithic zirconia.
Methods. Totally, 340 self-colored (A2) zirconia specimens from two different monolithic zirconia groups (n=170) were
prepared, measuring 15.5×12.5×1.2 mm. Then, 17 subgroups (n=10), including the control groups, were sintered according
to sintering parameters. XRD analysis was used to determine phase transformations. The surface roughness of the specimens
was evaluated using profilometry, and the flexural strength of the specimens was evaluated by the three-point bending test.
The data were analyzed using three-way ANOVA and post hoc multiple comparison test with Bonferroni correction (a=0.05)
at a significance level of 0.05. Independent-samples t-test was used to compare the subgroups between the control groups
(P˂0.05).
Results. No tetragonal-to-monoclinic phase transformation was observed in the groups. Changes in the sintering parameters
did not significantly affect the surface roughness and flexural strength of monolithic zirconia. Surface roughness values for
all the subgroups were above the clinically critical limit.
Conclusion. According to the results of this study, changes in the sintering parameters did not affect the surface phase
transformation, surface roughness, and flexural strength of monolithic zirconia.
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Affiliation(s)
- Caner Öztürk
- Department of Prosthodontics, Faculty of Dentistry, Hatay Mustafa Kemal University, Hatay, Turkey
| | - Gülşen Can
- Department of Prosthodontics, Faculty of Dentistry, İstanbul Aydın University, Istanbul, Turkey
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Spazzin AO, Schestatsky R, Ness CRB, Alessandretti R, Pereira GKR. Obtaining optimal esthetics with veneered zirconia and lithium disilicate frameworks on substrates of different colors. J ESTHET RESTOR DENT 2020; 32:540-544. [DOI: 10.1111/jerd.12578] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 02/17/2020] [Accepted: 02/22/2020] [Indexed: 11/29/2022]
Affiliation(s)
- Aloísio O. Spazzin
- Graduate Program in DentistryMeridional Faculty (IMED) Passo Fundo Brazil
| | | | - Carla R. B. Ness
- Graduate Program in DentistryMeridional Faculty (IMED) Passo Fundo Brazil
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Vila-Nova TEL, Gurgel de Carvalho IH, Moura DMD, Batista AUD, Zhang Y, Paskocimas CA, Bottino MA, de Assunção E Souza RO. Effect of finishing/polishing techniques and low temperature degradation on the surface topography, phase transformation and flexural strength of ultra-translucent ZrO 2 ceramic. Dent Mater 2020; 36:e126-e139. [PMID: 32008750 DOI: 10.1016/j.dental.2020.01.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 11/24/2019] [Accepted: 01/14/2020] [Indexed: 01/25/2023]
Abstract
OBJECTIVE To investigate the effect of different surface finishing and polishing regimes and low temperature degradation on flexural strength, phase transformation and surface topography of ultra-translucent ZrO2 ceramic. METHODS 300 (n=15/group) of conventional zirconia (Z: Ice Zirkon Transluzent) and ultra-translucent zirconia (UT: Prettau Anterior) bar-specimens were made and divided according to the "Finishing/Polishing" - (C - Control, B - diamond rubber polishers, P - adjusting with burs, PB - adjusting with burs+diamond polishers, PG - adjusting with burs+glaze), "Low temperature Degradation (LTD)" (with or without a treatment at 127°C, 1.7bar/24h). Then, a 3-point mini flexural test was performed in a universal testing machine (1mm/min, 500kgf load cell). SEM, EDS, XDR, AFM, optical profilometry and Weibull analysis were performed. Data were analyzed by 3-way ANOVA and Tukey's post-test (5%). RESULTS Groups ZPBD (1670±253MPa), ZBD (1664±217MPa), and ZB (1655±3678MPa) showed significantly higher flexural strength than the UTPG group (372±56MPa). The Weibull modulus was significantly higher for the ZPD group compared to the UB, UCD, UPD and UPBD, while UTB, UTCD and UTPD had the lowest value. Monoclinic phases were observed only in the conventional zirconia groups and were more evident after LTD. Diamond rubber polishers presented less roughness for both zirconias. SIGNIFICANCE The use of diamond rubber polishers is the most suitable finishing/polishing method for zirconia ceramic restorations and that final glazing reduces the fracture resistance of these materials.
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Affiliation(s)
- Taciana Emília Leite Vila-Nova
- Federal University of Rio Grande do Norte (UFRN), Department of Dentistry, Av. Salgado Filho, 1787, Lagoa Nova, Natal, RN, CEP: 59056-000, Brazil.
| | - Isabelle Helena Gurgel de Carvalho
- Federal University of Rio Grande do Norte (UFRN), Department of Dentistry, Division of Prosthodontics, Av. Salgado Filho, 1787, Lagoa Nova, Natal, RN, 59056-000, Brazil.
| | - Dayanne Monielle Duarte Moura
- Federal University of Rio Grande do Norte (UFRN), Department of Dentistry, Division of Prosthodontics, Av. Salgado Filho, 1787, Lagoa Nova, Natal, RN, 59056-000, Brazil.
| | - André Ulisses Dantas Batista
- Federal University of Paraíba (UFPB), Department of Restorative Dentistry, Conj. Pres. Castelo Branco III, João Pessoa, PB, 58033-455, Brazil.
| | - Yu Zhang
- New York University College of Dentistry, Department of Biomaterials and Biomimetics, 433 First Avenue, Room 810, New York, NY, 10010, United States.
| | - Carlos Alberto Paskocimas
- Federal University of Rio Grande do Norte (UFRN), Department of Material Engineering, Av. Salgado Filho, 3000, Lagoa Nova, Natal, RN, Brazil.
| | - Marco Antonio Bottino
- São Paulo State University (UNESP), Institute of Science and Technology, Av Engenheiro Francisco José Longo, 777, Jardim São Dimas, São José dos Campos, São Paulo, São José dos Campos, CEP: 12245-000, Brazil.
| | - Rodrigo Othávio de Assunção E Souza
- Adjunct Professor at Federal University of Rio Grande do Norte (UFRN), Department of Dentistry, Division of Prosthodontics, Av. Salgado Filho, 1787, Lagoa Nova, Natal, RN, 59056-000, Brazil.
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