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Tian JM, Ho WF, Hsu HC, Song Y, Wu SC. Evaluation of Feasibility on Dental Zirconia-Accelerated Aging Test by Chemical Immersion Method. MATERIALS (BASEL, SWITZERLAND) 2023; 16:7691. [PMID: 38138835 PMCID: PMC10744630 DOI: 10.3390/ma16247691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 12/07/2023] [Accepted: 12/12/2023] [Indexed: 12/24/2023]
Abstract
The aim of this study was to investigate the low-temperature degradation (LTD) kinetics of tetragonal zirconia with 3 mol% yttria (3Y-TZP) dental ceramic using two degradation methods: hydrothermal degradation and immersed degradation. To study transformation kinetics, we prepared 3Y-TZP powders. We pressed these powders uniaxially into a stainless mold at 100 MPa. We then sintered the compacted bodies at intervals of 50 °C between 1300 °C and 1550 °C and immersed the specimens at various temperatures from 60 °C to 80 °C in 4% acetic acid or from 110 °C to 140 °C for the hydrothermal method. We used a scanning electron microscope (SEM) to confirm crystalline grain size and used X-ray diffraction to analyze the zirconia phase. As the sintering temperature increased, the calculated crystalline grain size also increased. We confirmed this change with the SEM image. The higher sintering temperatures were associated with more phase transformation. According to the Mehl-Avrami-Johnson equation, the activation energies achieved using the hydrothermal method were 101 kJ/mol, 95 kJ/mol, and 86 kJ/mol at sintering temperatures of 1450 °C, 1500 °C, and 1550 °C, respectively. In addition, the activation energies of the specimens immersed in 4% acetic acid were 60 kJ/mol, 55 kJ/mol, 48 kJ/mol, and 35 kJ/mol, with sintered temperatures of 1400 °C, 1450 °C, 1500 °C, and 1550 °C, respectively. The results showed that a lower sintering temperature would restrain the phase transformation of zirconia because of the smaller crystalline grain size. As a result, the rate of LTD decreased.
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Affiliation(s)
- Ju-Mei Tian
- Department of Stomatology of Xiamen Medical College, Engineering Research Center of Stomatological Biomaterials, Fujian Province University, Xiamen 361023, China
| | - Wen-Fu Ho
- Department of Chemical and Materials Engineering, National University of Kaohsiung, Kaohsiung 81148, Taiwan;
| | - Hsueh-Chuan Hsu
- Department of Dental Technology and Materials Science, Central Taiwan University of Science and Technology, Taichung 40601, Taiwan;
| | - Yi Song
- Department of Dental Technology, School of Medical Technology, Taizhou Polytechnic College, Taizhou 225300, China;
| | - Shih-Ching Wu
- Department of Dental Technology and Materials Science, Central Taiwan University of Science and Technology, Taichung 40601, Taiwan;
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Kohal RJ, von Schierholz C, Nold J, Spies BC, Adolfsson E, Vach K, Burkhardt F. Influence of loading and aging on the fracture strength of an injection-molded two-piece zirconia implant restored with a zirconia abutment. Clin Oral Implants Res 2023; 34:105-115. [PMID: 36444693 DOI: 10.1111/clr.14022] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 10/31/2022] [Accepted: 11/22/2022] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To investigate the fracture strength and potential phase transformation of an injection-molded two-piece zirconia implant restored with a zirconia abutment after loading and/or aging. METHODS Thirty-two two-piece zirconia implants (4.0 mm diameter) restored with zirconia abutments were embedded according to ISO 14801 and divided into four groups (n = 8/group): Three groups were either exclusively hydrothermally treated (group HT; 85°C), dynamically loaded (group DL; 107 cycles; 98 N), or subjected to both treatments simultaneously (group DL/HT). One group remained untreated (group 0). A sample from each group was cross-sectioned and examined by scanning electron microscopy for possible crystal phase transformation. The remaining samples were then loaded to fracture in a static loading test. A one-way ANOVA was used for statistical analyses. RESULTS During dynamic loading, three implants of group DL and six implants of group DL/HT fractured at a load of 98 N. The fracture strength of group DL/HT (108 ± 141 Ncm) was significantly reduced compared to the other groups (group 0: 342 ± 36 Ncm; HT: 363 ± 49 Ncm; DL: 264 ± 198 Ncm) (p < .05). Fractures from group 0 and HT occurred at both implant and abutment level, whereas implants from group DL and DL/HT fractured only at implant level. A shallow monoclinic transformation zone of approximately 2 μm was observed following hydrothermal treatment. CONCLUSIONS Within the limitations of this study, it can be concluded that dynamic loading and the combination of loading and aging reduced the fracture strength of the implant abutment combination. Hydrothermal treatment caused a shallow transformation zone which had no influence on the fracture strength.
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Affiliation(s)
- Ralf-Joachim Kohal
- Department of Prosthetic Dentistry, Faculty of Medicine, Center for Dental Medicine, Medical Center - University of Freiburg, University of Freiburg, Freiburg, Germany
| | - Christopher von Schierholz
- Department of Prosthetic Dentistry, Faculty of Medicine, Center for Dental Medicine, Medical Center - University of Freiburg, University of Freiburg, Freiburg, Germany
| | - Julian Nold
- Department of Prosthetic Dentistry, Faculty of Medicine, Center for Dental Medicine, Medical Center - University of Freiburg, University of Freiburg, Freiburg, Germany
| | - Benedikt C Spies
- Department of Prosthetic Dentistry, Faculty of Medicine, Center for Dental Medicine, Medical Center - University of Freiburg, University of Freiburg, Freiburg, Germany
| | | | - Kirstin Vach
- Faculty of Medicine, Medical Center - University of Freiburg, Institute for Medical Biometry and Statistics, University of Freiburg, Freiburg, Germany
| | - Felix Burkhardt
- Department of Prosthetic Dentistry, Faculty of Medicine, Center for Dental Medicine, Medical Center - University of Freiburg, University of Freiburg, Freiburg, Germany
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Kohal RJ, Vach K, Butz F, Spies BC, Patzelt SBM, Burkhardt F. One-Piece Zirconia Oral Implants for the Support of Three-Unit Fixed Dental Prostheses: Three-Year Results from a Prospective Case Series. J Funct Biomater 2023; 14:jfb14010045. [PMID: 36662092 PMCID: PMC9864364 DOI: 10.3390/jfb14010045] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 01/09/2023] [Accepted: 01/11/2023] [Indexed: 01/15/2023] Open
Abstract
The objective was to investigate the clinical and radiological outcome of one-piece zirconia oral implants to support three-unit fixed dental prostheses (FDP) after three years in function. Twenty-seven patients were treated with a total of 54 implants in a one-stage surgery and immediate provisionalization. Standardized radiographs were taken at implant placement, after one year and after three years, to evaluate peri-implant bone loss. Soft-tissue parameters were also assessed. Linear mixed regression models as well as Wilcoxon Signed Rank tests were used for analyzing differences between groups and time points (p < 0.05). At the three-year evaluation, one implant was lost, resulting in a cumulative survival rate of 98.1%. The mean marginal bone loss amounted to 2.16 mm. An implant success grade I of 52% (bone loss of ≤2 mm) and success grade II of 61% (bone loss of ≤3 mm) were achieved. None of the evaluated baseline parameters affected bone loss. The survival rate of the zirconia implants was comparable to market-available titanium implants. However, an increased marginal bone loss was observed with a high peri-implantitis incidence and a resulting low implant success rate.
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Affiliation(s)
- Ralf-Joachim Kohal
- Department of Prosthetic Dentistry, Faculty of Medicine, Center for Dental Medicine, Medical Center-University of Freiburg, University of Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany
- Correspondence:
| | - Kirstin Vach
- Institute of Medical Biometry and Statistics, Faculty of Medicine, Medical Center-University of Freiburg, University of Freiburg, Zinkmattenstr. 6a, 79108 Freiburg, Germany
| | - Frank Butz
- Department of Prosthetic Dentistry, Faculty of Medicine, Center for Dental Medicine, Medical Center-University of Freiburg, University of Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany
- Private Dental Clinic, Belchenstr. 6a, 79189 Bad Krozingen, Germany
| | - Benedikt Christopher Spies
- Department of Prosthetic Dentistry, Faculty of Medicine, Center for Dental Medicine, Medical Center-University of Freiburg, University of Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany
| | - Sebastian Berthold Maximilian Patzelt
- Department of Prosthetic Dentistry, Faculty of Medicine, Center for Dental Medicine, Medical Center-University of Freiburg, University of Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany
- Private Dental Clinic, Am Dorfplatz 3, 78658 Zimmern ob Rottweil, Germany
| | - Felix Burkhardt
- Department of Prosthetic Dentistry, Faculty of Medicine, Center for Dental Medicine, Medical Center-University of Freiburg, University of Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany
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Riva V, Boccaccini D, Cannio M, Maioli M, Valle M, Romagnoli M, Mortalò C, Leonelli C. Insight into t->m transition of MW treated 3Y-PSZ ceramics by grazing incidence X-ray diffraction. Ann Ital Chir 2022. [DOI: 10.1016/j.jeurceramsoc.2021.09.054] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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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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Burkhardt F, Spies BC, Riemer L, Adolfsson E, Doerken S, Kohal RJ. Fracture resistance and crystal phase transformation of a one- and a two-piece zirconia implant with and without simultaneous loading and aging-An in vitro study. Clin Oral Implants Res 2021; 32:1288-1298. [PMID: 34352139 DOI: 10.1111/clr.13825] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 07/12/2021] [Accepted: 07/13/2021] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To evaluate the influence of artificial aging on the transformation propagation and fracture resistance of zirconia implants. METHODS One-piece (with integrated implant abutment, 1P; regular diameter [4.1mm]; n = 16) and two-piece (with separate implant abutment, 2P; wide diameter [5 mm]; n = 16) zirconia implants were embedded according to ISO 14801. A two-piece titanium-zirconium implant (Ti-Zr; 4.1 mm diameter) served as a control (n = 16). One subgroup (n = 8) of each system was simultaneously dynamically loaded (107 cycles; 98N) and hydrothermally aged (85°C, 58 days), while the other subgroup (n = 8) remained untreated. Finally, specimens were statically loaded to fracture. Potential crystal phase transformation was examined at cross sections using scanning electron microscopy (SEM). A multivariate linear regression model was applied for statistical analyses. RESULTS The fracture resistance of 1P (1,117 [SD = 38] N; loaded/aged: 1,009 [60] N), 2P (850 [36] N; loaded/aged: 799 [84] N), and Ti-Zr implants (1,338 [205] N; loaded/aged: 1,319 [247] N) was not affected significantly by loading/aging (p = .171). However, when comparing the systems, they revealed significant differences independent of loading/aging (p ≤ .001). Regarding the crystal structure, a transformation zone was observed in SEM images of 1P only after aging, while 2P showed a transformation zone even before aging. After hydrothermal treatment, an increase of this monoclinic layer was observed in both systems. CONCLUSIONS The Ti-Zr control implant showed higher fracture resistance compared to both zirconia implants. Loading/aging had no significant impact on the fracture resistance of both zirconia implants. The wide-body 2P zirconia implant was weaker than the regular body 1P implant.
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Affiliation(s)
- Felix Burkhardt
- Department of Prosthetic Dentistry, Faculty of Medicine, Medical Center - University of Freiburg, Center for Dental Medicine, University of Freiburg, Freiburg, Germany
| | - Benedikt C Spies
- Department of Prosthetic Dentistry, Faculty of Medicine, Medical Center - University of Freiburg, Center for Dental Medicine, University of Freiburg, Freiburg, Germany
| | - Lennart Riemer
- Department of Prosthetic Dentistry, Faculty of Medicine, Medical Center - University of Freiburg, Center for Dental Medicine, University of Freiburg, Freiburg, Germany
| | | | - Sam Doerken
- Medical Center - University of Freiburg, Institute for Medical Biometry and Statistics, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Ralf-Joachim Kohal
- Department of Prosthetic Dentistry, Faculty of Medicine, Medical Center - University of Freiburg, Center for Dental Medicine, University of Freiburg, Freiburg, Germany
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Gremillard L, Mattlet A, Mathevon A, Fabrègue D, Zberg B, Stephan M. Hydrothermal Ageing and Its Effect on Fracture Load of Zirconia Dental Implants. MATERIALS 2021; 14:ma14113103. [PMID: 34198831 PMCID: PMC8201318 DOI: 10.3390/ma14113103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 05/31/2021] [Accepted: 05/31/2021] [Indexed: 11/18/2022]
Abstract
Due to growing demand for metal-free dental restorations, dental ceramics, especially dental zirconia, represent an increasing share of the dental implants market. They may offer mechanical performances of the same range as titanium ones. However, their use is still restricted by a lack of confidence in their durability and, in particular, in their ability to resist hydrothermal ageing. In the present study, the ageing kinetics of commercial zirconia dental implants are characterized by X-ray diffraction after accelerated ageing in an autoclave at different temperatures, enabling their extrapolation to body temperature. Measurements of the fracture loads show no effect of hydrothermal ageing even after ageing treatments simulated a 90-year implantation.
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Affiliation(s)
- Laurent Gremillard
- Univ Lyon, CNRS, INSA Lyon, UCBL, MATEIS, UMR5510, 69621 Villeurbanne, France; (A.M.); (A.M.); (D.F.)
- Correspondence:
| | - Agnès Mattlet
- Univ Lyon, CNRS, INSA Lyon, UCBL, MATEIS, UMR5510, 69621 Villeurbanne, France; (A.M.); (A.M.); (D.F.)
| | - Alexandre Mathevon
- Univ Lyon, CNRS, INSA Lyon, UCBL, MATEIS, UMR5510, 69621 Villeurbanne, France; (A.M.); (A.M.); (D.F.)
| | - Damien Fabrègue
- Univ Lyon, CNRS, INSA Lyon, UCBL, MATEIS, UMR5510, 69621 Villeurbanne, France; (A.M.); (A.M.); (D.F.)
| | - Bruno Zberg
- Straumann AG, PeterMerian Weg 12, 4052 Basel, Switzerland; (B.Z.); (M.S.)
| | - Marc Stephan
- Straumann AG, PeterMerian Weg 12, 4052 Basel, Switzerland; (B.Z.); (M.S.)
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Roulet JF, Schepker KL, Truco A, Schwarz HC, Rocha MG. Biaxial flexural strength, crystalline structure, and grain size of new commercially available zirconia-based ceramics for dental appliances produced using a new slip-casting method. J Mech Behav Biomed Mater 2020; 114:104180. [PMID: 33158788 DOI: 10.1016/j.jmbbm.2020.104180] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 10/20/2020] [Accepted: 10/23/2020] [Indexed: 11/28/2022]
Abstract
OBJECTIVE The aim of this study was to evaluate the biaxial flexural strength, the crystalline structure, and the grain size of zirconia-based ceramics produced using a new slip-casting method. MATERIALS AND METHODS Yttria-stabilized Tetragonal Zirconia Polycrystal (Y-TZP) and Alumina Toughened Zirconia (ATZ) ceramics were purchased from different manufactures. For the experimental group, ceramics produced using a patent pending slip-casting method (Slurry, Decema GmbH) was used. Slurry ceramics (n = 42) with a diameter of 14 ± 0.2 mm were produced by a proprietary colloidal shaping process, sintered, and subsequently polished with a lapping process using 15 μm diamond particles to a thickness of 1.2 ± 0.2 mm. For the control group, ceramics produced using the hot isostatic pressure method (HIP, Metoxit AG) were used. HIP ceramics discs (n = 42) with a diameter of 15.5 ± 0.02 mm were produced by classical HIP method and subsequently machined to a thickness of 1.99 ± 0.04 mm 32 discs of each ceramic were submitted to a biaxial flexural strength test using an universal testing machine at a crosshead speed of 0.5 mm/min. Statistical analyses using two-way ANOVA and Weibull distribution were performed. 2 discs of each ceramic were analyzed using X-ray diffraction for grain crystalline phase quantification. 2 discs of each ceramic were thermally etched and scanning electron microscopy images were obtained for grain size analysis (ISO 13383-1:2012). 6 discs of each ceramic were used for density measurement using the Archimedes' method. RESULTS For both ATZ and Y-TZP ceramics, the biaxial flexural strength and the characteristic strength of ceramics produced using the Slurry method were significantly higher than ones of the ceramic produced using HIP. The structure analysis confirmed the superiority of the Slurry ceramics which had only 1.2% tetragonal phase compared to 11-16% for the HIP ceramics. Grain size distributions covered a wide range 50-800 nm; the ZrO2 grains of the Slurry ceramics were significantly smaller than the ones of the control ceramics, while the Al2O3 grain distributions were not affected by the manufacturing process. The manufacturing process had no influence on the density of both materials. CONCLUSIONS The Slurry method using a new proprietary slip-casting method to produce Y-TZP and ATZ dental ceramics presented higher biaxial flexural strength, less monoclinic phase and smaller ZrO2 grains.
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Affiliation(s)
- Jean-François Roulet
- University of Florida, Center of Dental Biomaterials, Department of Restorative Dental Science, College of Dentistry, Room D9-26, 1395 Center Drive, Gainesville, FL, 32610-0415, USA.
| | - Kristy Lee Schepker
- Research Service Center, Herbert Wertheim College of Engineering, University of Florida, PO BOX 116621, Gainesville, FL, 32611- 0001, USA
| | - Andres Truco
- Research Service Center, Herbert Wertheim College of Engineering, University of Florida, PO BOX 116621, Gainesville, FL, 32611- 0001, USA
| | | | - Mateus Garcia Rocha
- University of Florida, Center of Dental Biomaterials, Department of Restorative Dental Science, College of Dentistry, Room D9-26, 1395 Center Drive, Gainesville, FL, 32610-0415, USA
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Reliability of an injection-moulded two-piece zirconia implant with PEKK abutment after long-term thermo-mechanical loading. J Mech Behav Biomed Mater 2020; 110:103967. [PMID: 32851978 DOI: 10.1016/j.jmbbm.2020.103967] [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: 05/11/2020] [Revised: 06/29/2020] [Accepted: 07/01/2020] [Indexed: 01/18/2023]
Abstract
Zirconia implants are appreciated in some clinical indications in light of their aesthetic appearance and good biocompatibility. The aim of this work was to evaluate the performance of a newly developed two-piece zirconia/polyether ketone ketone (PEKK) implant-abutment combination after long-term cyclic loading in a hydrothermal environment, using a new protocol adapted from two available ISO standards. Sixteen implants (n = 8/group) were embedded according to ISO 14801 and divided into two groups: implants in the Observational Group (OG) were cyclically loaded for 60 days (98 N, 10 million loading cycles, 2 Hz) in 85 °C water in a chewing simulator, while non-loaded/non-aged implants (as-received) constituted the Control Group (CG). After 4.7 million loading cycles, one OG implant fractured in the chewing simulator. The surviving implants were compared to CG implants by X-ray diffraction (XRD) to investigate potential ageing as suggested by ISO 13356, but also μ-Raman spectroscopy, Focused-Ion-Beam - Scanning-Electron-Microscopy (FIB-SEM), and load-to-fracture. Ageing was shown to have limited influence on the evaluated zirconia implant, with increased monoclinic content after loading/ageing being to a shallow transformed zone of ~2 μm at the implant surface. However, OG implants showed a significantly decreased fracture load of 751 ± 231 N (CG: 995 ± 161 N; p = .046). These values enable clinical application, but the fact that one failure was recorded during cyclic fatigue along with the significant decrease in strength after cyclic loading/ageing suggest that there may be room for further optimization of especially the PEKK abutment. Furthermore, good agreement was observed between the fracture modes of the implant that failed during the cyclic fatigue experiment and the in vivo failure of one implant during pre-clinical trials, validating the interest of the in vitro protocol used in this work to check the reliability of zirconia implant.
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Bethke A, Pieralli S, Kohal RJ, Burkhardt F, von Stein-Lausnitz M, Vach K, Spies BC. Fracture Resistance of Zirconia Oral Implants In Vitro: A Systematic Review and Meta-Analysis. MATERIALS (BASEL, SWITZERLAND) 2020; 13:E562. [PMID: 31991565 PMCID: PMC7040771 DOI: 10.3390/ma13030562] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 01/15/2020] [Accepted: 01/21/2020] [Indexed: 12/27/2022]
Abstract
Various protocols are available to preclinically assess the fracture resistance of zirconia oral implants. The objective of the present review was to determine the impact of different treatments (dynamic loading, hydrothermal aging) and implant features (e.g., material, design or manufacturing) on the fracture resistance of zirconia implants. An electronic screening of two databases (MEDLINE/Pubmed, Embase) was performed. Investigations including > 5 screw-shaped implants providing information to calculate the bending moment at the time point of static loading to fracture were considered. Data was extracted and meta-analyses were conducted using multilevel mixed-effects generalized linear models (GLMs). The Šidák method was used to correct for multiple testing. The initial search resulted in 1864 articles, and finally 19 investigations loading 731 zirconia implants to fracture were analyzed. In general, fracture resistance was affected by the implant design (1-piece > 2-piece, p = 0.004), material (alumina-toughened zirconia/ATZ > yttria-stabilized tetragonal zirconia polycrystal/Y-TZP, p = 0.002) and abutment preparation (untouched > modified/grinded, p < 0.001). In case of 2-piece implants, the amount of dynamic loading cycles prior to static loading (p < 0.001) or anatomical crown supply (p < 0.001) negatively affected the outcome. No impact was found for hydrothermal aging. Heterogeneous findings of the present review highlight the importance of thoroughly and individually evaluating the fracture resistance of every zirconia implant system prior to market release.
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Affiliation(s)
- Annalena Bethke
- Department of Prosthodontics, Geriatric Dentistry and Craniomandibular Disorders, Charité—Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Aßmannshauser Str. 4-6, 14197 Berlin, Germany; (A.B.); (S.P.); (F.B.); (M.v.S.-L.)
| | - Stefano Pieralli
- Department of Prosthodontics, Geriatric Dentistry and Craniomandibular Disorders, Charité—Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Aßmannshauser Str. 4-6, 14197 Berlin, Germany; (A.B.); (S.P.); (F.B.); (M.v.S.-L.)
- Department of Prosthetic Dentistry, Faculty of Medicine, Center for Dental Medicine, Medical Center—University of Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany;
| | - Ralf-Joachim Kohal
- Department of Prosthetic Dentistry, Faculty of Medicine, Center for Dental Medicine, Medical Center—University of Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany;
| | - Felix Burkhardt
- Department of Prosthodontics, Geriatric Dentistry and Craniomandibular Disorders, Charité—Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Aßmannshauser Str. 4-6, 14197 Berlin, Germany; (A.B.); (S.P.); (F.B.); (M.v.S.-L.)
- Department of Prosthetic Dentistry, Faculty of Medicine, Center for Dental Medicine, Medical Center—University of Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany;
| | - Manja von Stein-Lausnitz
- Department of Prosthodontics, Geriatric Dentistry and Craniomandibular Disorders, Charité—Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Aßmannshauser Str. 4-6, 14197 Berlin, Germany; (A.B.); (S.P.); (F.B.); (M.v.S.-L.)
| | - Kirstin Vach
- Institute of Medical Biometry and Statistics, Faculty of Medicine, Medical Center—University of Freiburg, University of Freiburg, Stefan-Meier-Str. 26, 79104 Freiburg, Germany;
| | - Benedikt Christopher Spies
- Department of Prosthodontics, Geriatric Dentistry and Craniomandibular Disorders, Charité—Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Aßmannshauser Str. 4-6, 14197 Berlin, Germany; (A.B.); (S.P.); (F.B.); (M.v.S.-L.)
- Department of Prosthetic Dentistry, Faculty of Medicine, Center for Dental Medicine, Medical Center—University of Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany;
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Abstract
The market share of zirconia (ZrO2) dental implants is steadily increasing. This material comprises a polymorphous character with three temperature-dependent crystalline structures, namely monoclinic (m), tetragonal (t) and cubic (c) phases. Special attention is given to the tetragonal phase when maintained in a metastable state at room temperature. Metastable tetragonal grains allow for the beneficial phenomenon of Phase Transformation Toughening (PTT), resulting in a high fracture resistance, but may lead to an undesired surface transformation to the monoclinic phase in a humid environment (low-temperature degradation, LTD, often referred to as ‘ageing’). Today, the clinical safety of zirconia dental implants by means of long-term stability is being addressed by two international ISO standards. These standards impose different experimental setups concerning the dynamic fatigue resistance of the final product (ISO 14801) or the ageing behavior of a standardized sample (ISO 13356) separately. However, when evaluating zirconia dental implants pre-clinically, oral environmental conditions should be simulated to the extent possible by combining a hydrothermal treatment and dynamic fatigue. For failure analysis, phase transformation might be quantified by non-destructive techniques, such as X-Ray Diffraction (XRD) or Raman spectroscopy, whereas Scanning Electron Microscopy (SEM) of cross-sections or Focused Ion Beam (FIB) sections might be used for visualization of the monoclinic layer growth in depth. Finally, a minimum load should be defined for static loading to fracture. The purpose of this communication is to contribute to the current discussion on how to optimize the aforementioned standards in order to guarantee clinical safety for the patients.
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Monzavi M, Zhang F, Meille S, Douillard T, Adrien J, Noumbissi S, Nowzari H, Chevalier J. Influence of artificial aging on mechanical properties of commercially and non-commercially available zirconia dental implants. J Mech Behav Biomed Mater 2019; 101:103423. [PMID: 31536885 DOI: 10.1016/j.jmbbm.2019.103423] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 09/04/2019] [Accepted: 09/07/2019] [Indexed: 02/04/2023]
Abstract
OBJECTIVE To evaluate the effect of artificial aging on the mechanical resistance and micromechanical properties of commercially and noncommercially available zirconia dental implants. METHODS Scanning electron microscopy (SEM) and X-ray computed tomography (X-CT) were performed on implant systems including: Z-systems®, Straumann®, Zibone® and commercially and non-commercially available TAV dental® with varying grain sizes. Accelerated aging was performed at 134 °C and 2-bar pressure for 30 hours. Before and after aging, the mechanical load to failure was investigated and the bending moments were calculated. Nanoindentation responses of the representative Zibone implant before and after aging were performed to evaluate the effects of aging on hardness (H) and Young's modulus (E). A two-sample t-test statistical analysis was used to determine significant differences of bending moments within groups. RESULTS All implants presented with compact and homogenous core structures without porosities. The bending moment was significantly increased after aging for all groups (P ≤ 0.05) except for Z-systems (significant decrease (P = 0.022)) and TAV group 3 (no significant increase (P = 0.181)). The increase in bending moment was less pronounced with increasing grain size in TAV groups (group 1: P = 0.036, group 2: P = 0.05, group 3: P = 0.18). E and H were reduced approximately 32% and 18% respectively following aging within the transformed, microcracked zone of the presentative Zibone implant. CONCLUSIONS Aging led to both increase and decrease of the mechanical properties of the implant systems analyzed. The apparent contrast amongst groups can be explained based on differences in grain sizes and surface features. Aging decreased micromechanical properties of one implant system which warrants further investigation.
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Affiliation(s)
- Mona Monzavi
- Private Practice, 120 S Spalding Drive, Beverly Hills, CA, 90212, USA; Université de Lyon, INSA-Lyon, UMR CNRS 5510 MATEIS, 7 Avenue Jean Capelle, 69621, Villeurbanne Cedex, France.
| | - Fei Zhang
- Université de Lyon, INSA-Lyon, UMR CNRS 5510 MATEIS, 7 Avenue Jean Capelle, 69621, Villeurbanne Cedex, France
| | - Sylvain Meille
- Université de Lyon, INSA-Lyon, UMR CNRS 5510 MATEIS, 7 Avenue Jean Capelle, 69621, Villeurbanne Cedex, France
| | - Thierry Douillard
- Université de Lyon, INSA-Lyon, UMR CNRS 5510 MATEIS, 7 Avenue Jean Capelle, 69621, Villeurbanne Cedex, France
| | - Jérôme Adrien
- Université de Lyon, INSA-Lyon, UMR CNRS 5510 MATEIS, 7 Avenue Jean Capelle, 69621, Villeurbanne Cedex, France
| | - Sammy Noumbissi
- International Academy of Ceramic Implantology Zirconia Implant Research Group-ZIRG, 801 Wayne Avenue, Suite G200, Silver Spring, MD, 20910, USA
| | - Hessam Nowzari
- Private Practice, 120 S Spalding Drive, Beverly Hills, CA, 90212, USA
| | - Jérôme Chevalier
- Université de Lyon, INSA-Lyon, UMR CNRS 5510 MATEIS, 7 Avenue Jean Capelle, 69621, Villeurbanne Cedex, France
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13
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Mechanical behaviour of extremely tough TZP bioceramics. J Mech Behav Biomed Mater 2019; 90:395-403. [DOI: 10.1016/j.jmbbm.2018.11.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 10/17/2018] [Accepted: 11/01/2018] [Indexed: 02/04/2023]
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Thammajaruk P, Buranadham S, Thanatvarakorn O, Ferrari M, Guazzato M. Influence of glass-ceramic coating on composite zirconia bonding and its characterization. Dent Mater 2019; 35:105-113. [DOI: 10.1016/j.dental.2018.11.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 10/24/2018] [Accepted: 11/01/2018] [Indexed: 10/27/2022]
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15
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Translational research on clinically failed zirconia implants. Dent Mater 2018; 35:368-388. [PMID: 30551804 DOI: 10.1016/j.dental.2018.11.033] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 11/27/2018] [Accepted: 11/28/2018] [Indexed: 12/13/2022]
Abstract
OBJECTIVES To provide fractographic analysis of clinically fractured zirconia implants recovered with their cemented crown. To calculate bending moments, corresponding stress and crack onset location on the implant's fracture surface using a mathematical model integrating spatial coordinates of the crown-implant part and occlusal loading obtained from 2D and 3D images. METHODS 15 fractured zirconia implants parts (11 posterior and 4 anterior) with their all- ceramic crowns still cemented on it were recovered. The implants were first generations from four manufacturers (AXIS Biodental, Z-Systems, Straumann, Swiss Dental Solutions). The time-to-failure varied between 2weeks and 9years. Fractography was performed identifying the failure origin and characteristic surface crack features. From 2D and 3D digital images of the crown-implant part, spatial coordinates anchoring the crown's occlusal contacts with the implant's central axis and reference plane were integrated in a mathematical model spreadsheet. Loads of 500 N in total were selectively distributed over identified occlusal contacts from wear patterns. The resultant bending and torsion moments, corresponding shear, tensile, maximum principal stress and von Mises stress were calculated. The fracture crack onset location on the implant's fracture surface was given by an angular position with respect to an occlusal reference and compared with the location of the fracture origin identified from fractographic analysis. RESULTS Implants fractured from the periphery of the smaller inner diameter between two threads at the bone-entrance level except for one implant which failed half-way within the bone. The porous coating (AXIS Biodental) and the large grit alumina sandblasting (Z-System) created surface defects directly related to the fracture origin. The model spreadsheet showed how occlusal loading with respect to the implant's central axis affects bending moments and crack onset. Dominant loads distributed on contacts with important wear pattern provided a calculated crack onset location in good agreement with the fractographic findings of the fracture origin. SIGNIFICANCE Recovered broken zirconia implant parts with their restorative crowns can provide not only information regarding the failure origin using fractography but also knowledge regarding occlusal crown loading with respect to the implant's axis. The mathematical model was helpful in showing how occlusal loading affects the location of the fracture initiation site on clinical zirconia implant fracture cases.
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Lai X, Si W, Jiang D, Sun T, Shao L, Deng B. Effects of small-grit grinding and glazing on mechanical behaviors and ageing resistance of a super-translucent dental zirconia. J Dent 2017; 66:23-31. [PMID: 28916163 DOI: 10.1016/j.jdent.2017.09.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 07/31/2017] [Accepted: 09/11/2017] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVES The purpose of this study is to elucidate the effects of small-grit grinding on the mechanical behaviors and ageing resistance of a super-translucent dental zirconia and to investigate the necessity of glazing for the small-grit ground zirconia. METHODS Small-grit grinding was performed using two kinds of silicon carbide abrasive papers. The control group received no grinding. The unground surfaces and the ground surfaces were glazed by an experienced dental technician. Finally, the zirconia materials were thermally aged in water at 134°C for 5h. After aforementioned treatments, we observed the surface topography and the microstructures, and measured the extent of monoclinic phase, the nano-hardness and nano-modulus of the possible transformed zone and the flexural strength. RESULTS Small-grit grinding changed the surface topography. The zirconia microstructure did not change obviously after surface treatments and thermal ageing; however, the glaze in contact with zirconia showed cracks after thermal ageing. Small-grit grinding did not induce a phase transformation but improved the flexural strength and ageing resistance. Glazing prevented zirconia from thermal ageing but severely diminished the flexural strength. The nano-hardness and nano-modulus of the surface layer were increased by ultrafine grinding. CONCLUSIONS The results suggest that small-grit grinding is beneficial to the strength and ageing resistance of the super-translucent dental zirconia; however, glazing is not necessary and even impairs the strength for the super-translucent dental zirconia. CLINICAL SIGNIFICANCE This study is helpful to the researches about dental grinding tools and maybe useful for dentists to choose reasonable zirconia surface treatments.
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Affiliation(s)
- Xuan Lai
- Department of Stomatology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Wenjie Si
- School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
| | - Danyu Jiang
- State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Shanghai, 200050, China
| | - Ting Sun
- Department of Stomatology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Longquan Shao
- Department of Stomatology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China.
| | - Bin Deng
- Department of the Prosthodontics, The General Hospital of Chinese PLA, Beijing, 100853, China.
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Podwórny J, Staszewski M, Wojsa J. Investigations into the phase composition of zirconia-based sinters with an axial texture. J Appl Crystallogr 2017. [DOI: 10.1107/s1600576717004575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Owing to the phase transition of the tetragonal form of ZrO2 into the monoclinic one, caused by mechanical stresses, preparation of powder samples for quantitative phase analysis by the X-ray diffraction method should be avoided. The process of grinding of zirconia sinters leads to considerable changes in their phase composition. For this reason, a quantitative phase analysis should be conducted on solid samples not subjected to mechanical stresses, irrespective of problems appearing during experiments and analysis. One such problem is preferred crystallographic orientation (texture). This paper describes the influence of a preferred crystallographic orientation on the quantitative phase analysis conducted on solid samples and presents the results of an analysis in which corrections for uniaxial and multiaxial textures were applied. It was found that the examined samples had a very weak but nonzero multiaxial texture. The share of the randomly oriented fraction in the examined sinters was determined to be ca 94 vol.% and the share of the textured fraction ca 6 vol.%. From the statistical point of view, in the case of small amounts of the textured fraction, a correction on one distinguished crystallographic plane can overcome this problem. In the case of the slightly textured sinters of metering nozzles subjected to investigation here, the correction related to all the unique directions was statistically insignificant because the textured part corresponds to only a small volume fraction. However, corrections related to all texture axes considerably improve the fit of the calculated X-ray pattern with the experimental one and help to better characterize the examined materials.
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Asri RIM, Harun WSW, Samykano M, Lah NAC, Ghani SAC, Tarlochan F, Raza MR. Corrosion and surface modification on biocompatible metals: A review. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2017; 77:1261-1274. [PMID: 28532004 DOI: 10.1016/j.msec.2017.04.102] [Citation(s) in RCA: 197] [Impact Index Per Article: 28.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 04/18/2017] [Indexed: 12/12/2022]
Abstract
Corrosion prevention in biomaterials has become crucial particularly to overcome inflammation and allergic reactions caused by the biomaterials' implants towards the human body. When these metal implants contacted with fluidic environments such as bloodstream and tissue of the body, most of them became mutually highly antagonistic and subsequently promotes corrosion. Biocompatible implants are typically made up of metallic, ceramic, composite and polymers. The present paper specifically focuses on biocompatible metals which favorably used as implants such as 316L stainless steel, cobalt-chromium-molybdenum, pure titanium and titanium-based alloys. This article also takes a close look at the effect of corrosion towards the implant and human body and the mechanism to improve it. Due to this corrosion delinquent, several surface modification techniques have been used to improve the corrosion behavior of biocompatible metals such as deposition of the coating, development of passivation oxide layer and ion beam surface modification. Apart from that, surface texturing methods such as plasma spraying, chemical etching, blasting, electropolishing, and laser treatment which used to improve corrosion behavior are also discussed in detail. Introduction of surface modifications to biocompatible metals is considered as a "best solution" so far to enhanced corrosion resistance performance; besides achieving superior biocompatibility and promoting osseointegration of biocompatible metals and alloys.
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Affiliation(s)
- R I M Asri
- Institute of Postgraduate Studies, Universiti Malaysia Pahang, Lebuhraya Tun Razak, Gambang, 26300 Kuantan, Pahang, Malaysia
| | - W S W Harun
- Green Research for Advanced Materials Laboratory, Human Engineering Group, Faculty of Mechanical Engineering, Universiti Malaysia Pahang, 26600 Pekan, Pahang, Malaysia.
| | - M Samykano
- Structural and Material Degradation Group, Faculty of Mechanical Engineering, Universiti Malaysia Pahang, 26600 Pekan, Pahang, Malaysia
| | - N A C Lah
- Structural and Material Degradation Group, Faculty of Mechanical Engineering, Universiti Malaysia Pahang, 26600 Pekan, Pahang, Malaysia
| | - S A C Ghani
- Green Research for Advanced Materials Laboratory, Human Engineering Group, Faculty of Mechanical Engineering, Universiti Malaysia Pahang, 26600 Pekan, Pahang, Malaysia
| | - F Tarlochan
- Department of Mechanical and Industrial Engineering, College of Engineering, Qatar University, Doha, Qatar
| | - M R Raza
- Department of Mechanical Engineering, COMSATS Institute of Information Technology, Sahiwal 57000, Pakistan
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Borba M, de Araújo MD, Fukushima KA, Yoshimura HN, Griggs JA, Della Bona Á, Cesar PF. Effect of different aging methods on the mechanical behavior of multi-layered ceramic structures. Dent Mater 2016; 32:1536-1542. [PMID: 27726968 DOI: 10.1016/j.dental.2016.09.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 07/15/2016] [Accepted: 09/03/2016] [Indexed: 02/04/2023]
Abstract
OBJECTIVE To evaluate the effect of two aging methods (mechanical cycling and autoclave) on the mechanical behavior of veneer and framework ceramic specimens with different configurations (monolithic, two and three-layers). METHODS Three ceramics used as framework for fixed dental prostheses (YZ-Vita In-Ceram YZ; IZ-Vita In-Ceram Zirconia; AL-Vita In-Ceram AL) and two veneering porcelains (VM7 and VM9) were studied. Bar-shaped specimens were produced in three different designs: monolithic, two layers (porcelain-framework) and three layers (porcelain-framework-porcelain). Specimens were tested for three-point flexural strength at 1MPa/s in 37°C artificial saliva. Three different experimental conditions were evaluated (n=10): control; mechanical cycling (2Hz, 37°C artificial saliva); and autoclave aging (134°C, 2 bars, 5h). Bi-layered specimens were tested in both conditions: with porcelain or framework ceramic under tension. Fracture surfaces were analyzed using stereomicroscope and scanning electron microscopy. Results were statistically analyzed using Kruskal-Wallis and Student-Newman-Keuls tests. RESULTS Only for AL group, mechanical cycling and autoclave aging significantly decreased the flexural strength values in comparison to the control (p<0.01). YZ, AL, VM7 and VM9 monolithic groups showed no strength degradation. For multi-layered specimens, when the porcelain layer was tested in tension (bi and tri-layers), the aging methods evaluated also had no effect on strength (p≥0.05). Total and partial failure modes were identified. SIGNIFICANCE Mechanical cycling and autoclave aging protocols had no effect on the flexural strength values and failure behavior of YZ and IZ ceramic structures. Yet, AL monolithic structures showed a significant decrease in flexural strength with any of the aging methods.
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Affiliation(s)
- Márcia Borba
- Post-graduate Program in Dentistry, Dental School, University of Passo Fundo, Passo Fundo, RS, Brazil.
| | - Maico D de Araújo
- Department of Biomaterials and Oral Biology, University of Sao Paulo, Sao Paulo, SP, Brazil
| | - Karen A Fukushima
- Department of Biomaterials and Oral Biology, University of Sao Paulo, Sao Paulo, SP, Brazil
| | - Humberto N Yoshimura
- Center for Engineering, Modeling and Applied Social Sciences, Federal University of ABC, Santo Andre, SP, Brazil
| | - Jason A Griggs
- Department of Biomedical Materials Science, University of Mississippi Medical Center, Jackson, MS, USA
| | - Álvaro Della Bona
- Post-graduate Program in Dentistry, Dental School, University of Passo Fundo, Passo Fundo, RS, Brazil
| | - Paulo F Cesar
- Department of Biomaterials and Oral Biology, University of Sao Paulo, Sao Paulo, SP, Brazil
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Complexity of the relationships between the sintering-temperature-dependent grain size, airborne-particle abrasion, ageing and strength of 3Y-TZP ceramics. Dent Mater 2016; 32:510-8. [DOI: 10.1016/j.dental.2015.12.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 09/23/2015] [Accepted: 12/07/2015] [Indexed: 02/04/2023]
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Cattani-Lorente M, Durual S, Amez-Droz M, Wiskott HWA, Scherrer SS. Hydrothermal degradation of a 3Y-TZP translucent dental ceramic: A comparison of numerical predictions with experimental data after 2 years of aging. Dent Mater 2016; 32:394-402. [PMID: 26777095 DOI: 10.1016/j.dental.2015.12.015] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 11/24/2015] [Accepted: 12/07/2015] [Indexed: 11/19/2022]
Abstract
OBJECTIVES The purpose of the study was to assess the hydrothermal resistance of a translucent zirconia with two clinical relevant surface textures by means of accelerated tests (LTD) and to compare predicted monoclinic fractions with experimental values measured after two years aging at 37°C. METHODS Polished (P) and ground (G) specimens were subjected to hydrothermal degradation by exposure to water steam at different temperatures and pressures. The t-m phase transformation was quantified by grazing incidence X-ray diffraction (GIXDR). The elastic modulus and hardness before- and after LTD were determined by nanoindentation. RESULTS G specimens presented a better resistance to hydrothermal degradation than P samples. Activation energies of 89 and 98kJ/mol and b coefficients of 2.0×10(-5) and 1.8×10(-6) were calculated for P and G samples respectively. The coefficients were subsequently used to predict transformed monoclinic fractions at 37°C. A good correlation was found between the predicted values and the experimental data obtained after aging at 37°C during 2 years. Hydrothermal degradation led to a significant decrease of the elastic moduli and hardness in both groups. SIGNIFICANCE The dependency of the t-m phase transformation rate on temperature must be determined to accurately predict the hydrothermal behavior of the zirconia ceramics at oral temperatures. The current prevailing assumption, that 5h aging at 134°C corresponds to 15-20 years at 37°C, will underestimate the transformed fraction of the translucent ceramic at 37°C. In this case, the mechanical surface treatment influences the ceramic's transformability. While mild grinding could potentially retard the hydrothermal transformation, polishing after occlusal adjustment is recommended to prevent wear of the antagonist teeth and maintain structural strength.
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Affiliation(s)
- Maria Cattani-Lorente
- Division of Fixed Prosthodontics and Biomaterials, University Clinic of Dental Medicine, University of Geneva, Geneva, Switzerland.
| | - Stéphane Durual
- Division of Fixed Prosthodontics and Biomaterials, University Clinic of Dental Medicine, University of Geneva, Geneva, Switzerland
| | - Michel Amez-Droz
- HEPIA, University of Applied Sciences - Western Switzerland, Geneva, Switzerland
| | - H W Anselm Wiskott
- Division of Fixed Prosthodontics and Biomaterials, University Clinic of Dental Medicine, University of Geneva, Geneva, Switzerland
| | - Susanne S Scherrer
- Division of Fixed Prosthodontics and Biomaterials, University Clinic of Dental Medicine, University of Geneva, Geneva, Switzerland
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Camposilvan E, Marro FG, Mestra A, Anglada M. Enhanced reliability of yttria-stabilized zirconia for dental applications. Acta Biomater 2015; 17:36-46. [PMID: 25641645 DOI: 10.1016/j.actbio.2015.01.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Revised: 12/12/2014] [Accepted: 01/19/2015] [Indexed: 02/04/2023]
Abstract
An increasing number of dental applications based on yttria-stabilized zirconia (3 Y-TZP) have been developed in recent years as a result of the advances and versatility of dry-processing and soft machining at the pre-sintered state. Nonetheless, the long-term surface stability of these materials in humid environment is still a matter of concern and may limit its application. In this work, a simple method to prevent hydrothermal degradation on the zirconia surface is studied in detail. This method involves the infiltration of pre-sintered parts with optimized solutions containing Ce salts, leaving unchanged the other processing steps, allowing the diffusion of Ce during conventional sintering. Several pre-sintering conditions, solution concentrations and sintering temperatures were studied and characterized, obtaining working parameters for the production of zirconia parts with mechanical properties similar to standard 3 Y-TZP and high resistance to hydrothermal aging. This optimal combination was obtained with the 1150 °C pre-sintering temperature, 50 wt.% solution and sintering at 1450 °C, leading to a superficial CeO2 content of about 3 mol.%.
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Affiliation(s)
- Erik Camposilvan
- Department of Materials Science and Metallurgical Engineering, Universitat Politècnica de Catalunya, Av. Diagonal 647, 08028 Barcelona, Spain; Center for Research in NanoEngineering CRnE, Universitat Politècnica de Catalunya, Av. Diagonal 647, 08028 Barcelona, Spain
| | - Fernando Garcia Marro
- Department of Materials Science and Metallurgical Engineering, Universitat Politècnica de Catalunya, Av. Diagonal 647, 08028 Barcelona, Spain; Center for Research in NanoEngineering CRnE, Universitat Politècnica de Catalunya, Av. Diagonal 647, 08028 Barcelona, Spain
| | - Alvaro Mestra
- Department of Materials Science and Metallurgical Engineering, Universitat Politècnica de Catalunya, Av. Diagonal 647, 08028 Barcelona, Spain; Center for Research in NanoEngineering CRnE, Universitat Politècnica de Catalunya, Av. Diagonal 647, 08028 Barcelona, Spain
| | - Marc Anglada
- Department of Materials Science and Metallurgical Engineering, Universitat Politècnica de Catalunya, Av. Diagonal 647, 08028 Barcelona, Spain; Center for Research in NanoEngineering CRnE, Universitat Politècnica de Catalunya, Av. Diagonal 647, 08028 Barcelona, Spain.
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The Effect of Cerium Oxide Addition on the Properties and Behavior of Y-TZP. INTERNATIONAL SCHOLARLY RESEARCH NOTICES 2014; 2014:828197. [PMID: 27437471 PMCID: PMC4897199 DOI: 10.1155/2014/828197] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 08/28/2014] [Accepted: 09/02/2014] [Indexed: 11/18/2022]
Abstract
The effects of CeO2 addition on the sintering behavior and mechanical properties of Y-TZP have been investigated over a wide sintering regime by pressureless sintering. It has been revealed that small additions of CeO2 (0.3-1.0 wt%) to Y-TZP were beneficial in enhancing the mechanical properties and hydrothermal ageing resistance of Y-TZP. Sintered samples were used to evaluate the bulk density, Vickers's hardness, Young's modulus, and fracture toughness of the material. CeO2 doped Y-TZPs were sintered at relatively low temperatures (1250°C and 1350°C) retaining high bulk density (>97% of theoretical density) and high Young's modulus (>200 GPa) without sacrificing tetragonal phase stability. The optimum level of dopant was found to be at 0.5 wt% for sintering between 1250°C and 1450°C using the standard 2 h holding time cycle, with sintered body exhibiting excellent combination of properties when compared to the undoped ceramics. In this experiment, the addition of 0.5 wt% recorded a bulk density reading of 5.9 g/cm(3), Vickers hardness value of 13.2 GPa, Young's modulus value of 211 GPa, and fracture toughness of 6.4 MPam(1/2), respectively, in a temperature range of 1400-1450°C.
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