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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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Rosentritt M, Preis V, Behr M, Strasser T. Fatigue and wear behaviour of zirconia materials. J Mech Behav Biomed Mater 2020; 110:103970. [DOI: 10.1016/j.jmbbm.2020.103970] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 06/29/2020] [Accepted: 07/01/2020] [Indexed: 01/10/2023]
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Microstructural, mechanical, and optical characterization of an experimental aging-resistant zirconia-toughened alumina (ZTA) composite. Dent Mater 2020; 36:e365-e374. [PMID: 32943230 DOI: 10.1016/j.dental.2020.08.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 07/05/2020] [Accepted: 08/29/2020] [Indexed: 02/04/2023]
Abstract
OBJECTIVE To evaluate the effect of aging on the microstructural, mechanical, and optical properties of an experimental zirconia-toughened alumina composite with 80%Al2O3 and 20%ZrO2 (ZTA Zpex) compared to a translucent zirconia (Zpex) and Alumina. METHODS Disc-shaped specimens were obtained by uniaxial and isostatic pressing the synthesized powders (n = 70/material). After sintering and polishing, half of the specimens underwent aging (20 h, 134 °C, 2.2 bar). Crystalline content and microstructure were evaluated using X-ray diffraction and scanning electron microscopy, respectively. Specimens underwent biaxial flexural strength testing to determine the characteristic stress, Weibull modulus, and reliability. Translucency parameter (TP) and Contrast ratio (CR) were calculated to characterize optical properties. RESULTS ZTA Zpex demonstrated a compact surface with a uniform dispersion of zirconia particles within the alumina matrix, and typical alumina and zirconia crystalline content. ZTA Zpex and alumina exhibited higher CR and lower TP than Zpex. ZTA Zpex and Zpex showed significantly higher characteristic stress relative to alumina. While aging did not affect optical and mechanical properties of ZTA Zpex and alumina, Zpex demonstrated a significant increase in translucency, as well as a in characteristic stress. Alumina reliability was significantly lower than others at 300 MPa, ZTA Zpex and Zpex reliability decreased at 800 MPa, except for aged Zpex. SIGNIFICANCE While aging did not affect the mechanical nor the optical properties of ZTA Zpex and alumina, it did alter both properties of Zpex. The results encourage further investigations to engineer ZTA as a framework material for long span fixed dental prostheses specially where darkened substrates, such as titanium implant abutments or endodontically treated teeth, demand masking.
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Benalcazar Jalkh EB, Monteiro KN, Cesar PF, Genova LA, Bergamo ETP, Lopes ACDO, Lima E, Lisboa-Filho PN, Campos TMB, Witek L, Coelho PG, Borges AFS, Bonfante EA. Aging resistant ZTA composite for dental applications: Microstructural, optical and mechanical characterization. Dent Mater 2020; 36:1190-1200. [PMID: 32561117 DOI: 10.1016/j.dental.2020.05.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Revised: 05/03/2020] [Accepted: 05/24/2020] [Indexed: 02/04/2023]
Abstract
OBJECTIVE To synthesize a zirconia toughened alumina (ZTA) composite with 70% alumina reinforced by 30% zirconia for dental applications and to characterize its microstructure and optical properties for comparison with the isolated counterpart materials and a first-generation 3Y-TZP. METHODS Disc-shaped specimens were divided in four groups (n = 70/material): (1) 3YSB-E (first generation 3Y-TZP), (2) Zpex (second generation 3Y-TZP), (3) alumina, and (4) ZTA-Zpex 70/30. After synthesis, ceramic powders were pressed, and green-body samples sintered following a predetermined protocol. Specimens were polished to obtain a mirror surface finish. Apparent density was measured by Archimedes principle. X-ray diffraction (XRD) and scanning electron microscope (SEM) were used to characterize the crystalline content and microstructure. Reflectance tests were performed to determine the contrast-ratio (CR) and translucency-parameter (TP). Mechanical properties were assessed by biaxial flexural strength (BFS) test. All analyses were conducted before and after artificial aging (20 h, 134 °C, 2.2 bar). Optical parameters were evaluated through repeated-measures analysis of variance and Tukey tests (p < 0.05). BFS data were analyzed using Weibull statistics (95% CI). RESULTS High density values (95-99%) were found for all ceramic materials and SEM images exhibited a dense microstructure. While XRD patterns revealed the preservation of crystalline content in the ZTA composite, an increase in the monoclinic peak was observed for pure zirconias after aging. Significantly higher CR and lower TP values were observed for the ZTA composite, followed by alumina, 3YSB-E, and Zpex. The highest characteristic stress was recorded for 3YSB-E, followed by intermediate values between ZTA and Zpex, and the lowest for alumina. Aging affected the optical and mechanical properties of both zirconias, while remained stable for ZTA composite and alumina. SIGNIFICANCE The synthesis of experimental 70-30% ZTA composite was successful and its relevance for dental applications relies on its higher masking ability, aging resistance, and strength similar to zirconia.
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Affiliation(s)
- Ernesto Byron Benalcazar Jalkh
- Department of Prosthodontics and Periodontology, University of São Paulo, Bauru School of Dentistry, Bauru, SP, Brazil; Department of Biomaterials and Biomimetics, New York University College of Dentistry, New York, NY, USA.
| | - Kelli Nunes Monteiro
- Department of Biomaterials and Oral Biology, University of São Paulo, School of Dentistry, SP, Brazil
| | - Paulo Francisco Cesar
- Department of Biomaterials and Oral Biology, University of São Paulo, School of Dentistry, SP, Brazil
| | | | - Edmara T P Bergamo
- Department of Prosthodontics and Periodontology, University of São Paulo, Bauru School of Dentistry, Bauru, SP, Brazil
| | | | - Erick Lima
- Department of Biomaterials and Oral Biology, University of São Paulo, School of Dentistry, SP, Brazil
| | | | | | - Lukasz Witek
- Department of Biomaterials and Biomimetics, New York University College of Dentistry, New York, NY, USA; Department of Biomedical Engineering, New York University, Tandon School of Engineering, Brooklyn, NY, USA
| | - Paulo G Coelho
- Department of Biomaterials and Biomimetics, New York University College of Dentistry, New York, NY, USA; Hansjörg Wyss Department of Plastic Surgery, NYU Langone Medical Center, New York, NY, USA; Mechanical and Aerospace Engineering, NYU Tandon School of Engineering, New York, NY, USA
| | - Ana Flavia Sanches Borges
- Department of Operative Dentistry, Endodontics and Dental Materials, University of São Paulo - Bauru School of Dentistry, Bauru, SP, Brazil
| | - Estevam A Bonfante
- Department of Prosthodontics and Periodontology, University of São Paulo, Bauru School of Dentistry, Bauru, SP, Brazil
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Aging resistance of an experimental zirconia-toughened alumina composite for large span dental prostheses: Optical and mechanical characterization. J Mech Behav Biomed Mater 2020; 104:103659. [DOI: 10.1016/j.jmbbm.2020.103659] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 01/21/2020] [Accepted: 01/27/2020] [Indexed: 02/04/2023]
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Ding Q, Zhang L, Bao R, Zheng G, Sun Y, Xie Q. Effects of different surface treatments on the cyclic fatigue strength of one-piece CAD/CAM zirconia implants. J Mech Behav Biomed Mater 2018; 84:249-257. [PMID: 29803139 DOI: 10.1016/j.jmbbm.2018.05.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 04/26/2018] [Accepted: 05/02/2018] [Indexed: 11/27/2022]
Abstract
OBJECTIVES The effects of different surface treatments on cyclic fatigue strengths of computer-aided design and computer-aided manufacturing (CAD/CAM) zirconia implants and its mechanisms were evaluated. MATERIAL AND METHODS One-piece cylindrical screw-type zirconia (Y-TZP) implants with diameters of 4.1-mm were fabricated using CAD/CAM technique; they were divided into four groups according to the type of surface treatment: (i) sintering (control group, CTRL), (ii) sandblasting (SB), (iii) sandblasting and etching with an experimental hot etching solution (SB-ST), and (iv) sandblasting and etching with hydrofluoric acid (SB-HF). The surface morphology and roughness of the implants were evaluated. Tetragonal to monoclinic transformation was measured on the surface by micro Raman spectroscopy. Static and fatigue tests were carried out at room temperature following the ISO 14801:2014 Standard. The cyclic fatigue strength of each group was determined using the staircase method. Specimens that survived the fatigue test were statically loaded to measure the residual fracture strength. RESULTS Among the four groups, SB-HF exhibited the highest surface roughness. Compared with the CTRL group, the surface monoclinic content was higher after all three types of surface treatments, amongst which, SB-HF had the highest content (39.14%), significantly more than the other three groups (P < 0.01). The cyclic fatigue strengths of CTRL, SB, SB-ST, and SB-HF implants were 530 N, 662.5 N, 705 N, and 555 N, respectively. The fracture strength after fatigue loading was higher than that before fatigue loading with no significant difference (P>0.05). CONCLUSIONS SB and SB-ST remarkably enhanced the fatigue resistance of zirconia implants, while SB-HF did not. One-piece 4.1-mm diameter CAD/CAM zirconia implants have sufficient durability for application in dental implants.
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Affiliation(s)
- Qian Ding
- Department of Prosthodontics, Peking University School and Hospital of Stomatology, 22 South Street ZhongGuanCun, Haidian District, Beijing 100081, China
| | - Lei Zhang
- Department of Prosthodontics, Peking University School and Hospital of Stomatology, 22 South Street ZhongGuanCun, Haidian District, Beijing 100081, China.
| | - Rui Bao
- Institute of Solid Mechanics, School of Aeronautic Science and Engineering, Beihang University, No. 37 Xueyuan Road, Haidian District, Beijing 100191, China
| | - Gang Zheng
- Department of Dental Materials, Peking University School and Hospital of Stomatology; National Engineering Laboratory for Digital and Material Technology of Stomatology, Peking University, 22 South Street ZhongGuanCun, Haidian District, Beijing 100081, China
| | - Yuchun Sun
- Center of Digital Dentistry, Peking University School and Hospital of Stomatology; National Engineering Laboratory for Digital and Material Technology of Stomatology; Research Center of Engineering and Technology for Digital Dentistry, Ministry of Health, 22 South Street ZhongGuanCun, Haidian District, Beijing 100081, China
| | - Qiufei Xie
- Department of Prosthodontics, Peking University School and Hospital of Stomatology, 22 South Street ZhongGuanCun, Haidian District, Beijing 100081, China
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Al-Shehri EZ, Al-Zain AO, Sabrah AH, Al-Angari SS, Al Dehailan L, Eckert GJ, Özcan M, Platt JA, Bottino MC. Effects of air-abrasion pressure on the resin bond strength to zirconia: a combined cyclic loading and thermocycling aging study. Restor Dent Endod 2017; 42:206-215. [PMID: 28808637 PMCID: PMC5553020 DOI: 10.5395/rde.2017.42.3.206] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 04/06/2017] [Indexed: 11/11/2022] Open
Abstract
OBJECTIVES To determine the combined effect of fatigue cyclic loading and thermocycling (CLTC) on the shear bond strength (SBS) of a resin cement to zirconia surfaces that were previously air-abraded with aluminum oxide (Al2O3) particles at different pressures. MATERIALS AND METHODS Seventy-two cuboid zirconia specimens were prepared and randomly assigned to 3 groups according to the air-abrasion pressures (1, 2, and 2.8 bar), and each group was further divided into 2 groups depending on aging parameters (n = 12). Panavia F 2.0 was placed on pre-conditioned zirconia surfaces, and SBS testing was performed either after 24 hours or 10,000 fatigue cycles (cyclic loading) and 5,000 thermocycles. Non-contact profilometry was used to measure surface roughness. Failure modes were evaluated under optical and scanning electron microscopy. The data were analyzed using 2-way analysis of variance and χ2 tests (α = 0.05). RESULTS The 2.8 bar group showed significantly higher surface roughness compared to the 1 bar group (p < 0.05). The interaction between pressure and time/cycling was not significant on SBS, and pressure did not have a significant effect either. SBS was significantly higher (p = 0.006) for 24 hours storage compared to CLTC. The 2 bar-CLTC group presented significantly higher percentage of pre-test failure during fatigue compared to the other groups. Mixed-failure mode was more frequent than adhesive failure. CONCLUSIONS CLTC significantly decreased the SBS values regardless of the air-abrasion pressure used.
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Affiliation(s)
- Eman Z Al-Shehri
- Division of Dental Biomaterials, Department of Biomedical and Applied Sciences, Indiana University School of Dentistry, Indianapolis, IN, USA.,Department of Restorative Dental Sciences, King Saud University College of Dentistry, Riyadh, Kingdom of Saudi Arabia
| | - Afnan O Al-Zain
- Division of Dental Biomaterials, Department of Biomedical and Applied Sciences, Indiana University School of Dentistry, Indianapolis, IN, USA.,Department of Operative Dentistry, King Abdulaziz University Faculty of Dentistry, Jeddah, Kingdom of Saudi Arabia
| | - Alaa H Sabrah
- Division of Dental Biomaterials, Department of Biomedical and Applied Sciences, Indiana University School of Dentistry, Indianapolis, IN, USA.,Department of Conservative Dentistry, The University of Jordan College of Dentistry, Amman, Jordan
| | - Sarah S Al-Angari
- Division of Dental Biomaterials, Department of Biomedical and Applied Sciences, Indiana University School of Dentistry, Indianapolis, IN, USA.,Department of Restorative Dental Sciences, King Saud University College of Dentistry, Riyadh, Kingdom of Saudi Arabia
| | - Laila Al Dehailan
- Division of Dental Biomaterials, Department of Biomedical and Applied Sciences, Indiana University School of Dentistry, Indianapolis, IN, USA.,Department of Restorative Dental Sciences, University of Dammam College of Dentistry, Dammam, Kingdom of Saudi Arabia
| | - George J Eckert
- Department of Biostatistics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Mutlu Özcan
- Dental Materials Unit, Center for Dental and Oral Medicine, Clinic for Fixed and Removable Prosthodontics and Dental Materials Science, University of Zurich, Zurich, Switzerland
| | - Jeffrey A Platt
- Division of Dental Biomaterials, Department of Biomedical and Applied Sciences, Indiana University School of Dentistry, Indianapolis, IN, USA
| | - Marco C Bottino
- Division of Dental Biomaterials, Department of Biomedical and Applied Sciences, Indiana University School of Dentistry, Indianapolis, IN, USA
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Muñoz EM, Longhini D, Antonio SG, Adabo GL. The effects of mechanical and hydrothermal aging on microstructure and biaxial flexural strength of an anterior and a posterior monolithic zirconia. J Dent 2017; 63:94-102. [PMID: 28591620 DOI: 10.1016/j.jdent.2017.05.021] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 05/03/2017] [Accepted: 05/30/2017] [Indexed: 02/07/2023] Open
Abstract
OBJECTIVES To evaluate the effect of hydrothermal aging (H), mechanical cycling (M), and the combination of hydrothermal plus mechanical cycling (H+M) on biaxial flexural strength (BFS) and microstructure of two monolithic zirconias, indicated for anterior (AMZ) or posterior restorations (PMZ) and a conventional zirconia (IZr). METHODS Disc specimens of each material (n=12) were submitted to: i) H (8h in autoclave at 134°C); ii) M (106 cycles, at 40% of BFS); and iii) H+M. BFS was measured (ISO-6872) and Weibull modulus (m) and the characteristic strength (σ0) were calculated. crystalline phase composition analyzed by XRD, and grain size measured by MEV analysis. RESULTS XRD analysis showed AMZ was not susceptible to monoclinic transformation in any treatment. Conventional zirconia (IZr) and PMZ had monoclinic transformation only after H and H+M. BFS of AMZ was lower than PMZ and IZr. Cubic phase was found in all conditions for AMZ and IZr, while it was identified in PMZ only after H and H+M. BFS of AMZ was affected by M and H+M. For IZr and PMZ the unique difference detected in BFS was in the comparison of H to M. H treatment induced lower Weibull modulus, but characteristic strength was compatible with the BFS results. AMZ grain size (μm2) was 8.6 times larger than PMZ grains, and 13.6 times larger than IZr grains. CONCLUSIONS AMZ showed the largest mean grain size, had the lowest BFS values, and was affected when mechanical cycling was involved. Monoclinic transformation was not found in any treatment for AMZ, but was found in IZr and PMZ when hydrothermal aging was used alone or when combined with mechanical cycling. PMZ showed similar behavior to the IZr. H induced to higher fracture probability. CLINICAL SIGNIFICANCE Translucent monolithic dental zirconia available on the market may behave differently under simulated oral aging. The relationship between composition and microstructure determines their properties presumably, and clinical performance.
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Affiliation(s)
- Eduardo Mariscal Muñoz
- Department of Dental Materials and Prosthodontics, Araraquara Dental School, Univ Estadual Paulista-UNESP, São Paulo, Brazil
| | - Diogo Longhini
- Department of Dental Materials and Prosthodontics, Araraquara Dental School, Univ Estadual Paulista-UNESP, São Paulo, Brazil
| | - Selma Gutierres Antonio
- Department of Physical Chemistry, Araraquara Institute of Chemistry, Univ Estadual Paulista-UNESP, São Paulo, Brazil
| | - Gelson Luis Adabo
- Department of Dental Materials and Prosthodontics, Araraquara Dental School, Univ Estadual Paulista-UNESP, São Paulo, Brazil.
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Aurélio IL, Dorneles LS, May LG. Extended glaze firing on ceramics for hard machining: Crack healing, residual stresses, optical and microstructural aspects. Dent Mater 2017; 33:226-240. [DOI: 10.1016/j.dental.2016.12.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 12/07/2016] [Accepted: 12/08/2016] [Indexed: 11/29/2022]
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Pereira GKR, Muller C, Wandscher VF, Rippe MP, Kleverlaan CJ, Valandro LF. Comparison of different low-temperature aging protocols: its effects on the mechanical behavior of Y-TZP ceramics. J Mech Behav Biomed Mater 2016; 60:324-330. [PMID: 26921592 DOI: 10.1016/j.jmbbm.2016.02.017] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Revised: 02/09/2016] [Accepted: 02/10/2016] [Indexed: 10/22/2022]
Abstract
This study evaluated the effect of different protocols of low-temperature degradation simulation on the mechanical behavior (structural reliability and flexural strength), the surface topography (roughness), and phase transformation of a Y-TZP ceramic. Disc-shaped specimens (1.2mm×12mm, Lava Frame, 3M ESPE, Seefeld, Germany) were manufactured according to ISO:6872-2008 and divided (n=30) according to the aging protocol executed: "Ctrl" - as-sintered - without any treatment; "Dist Water" - stored at distilled water at 37°C for 365 days; "MC" mechanical cycling into two steps: First - 200N, 2.2Hz for 2.000.000 cycles, Second - 450N, 10Hz for 1.000.000 cycles; "Aut" - steam autoclave at 134°C, 2bar (200kPa) for 20h; "Aut+MC"- Aut and MC methods. Roughness analysis (μm) showed, for Ra parameter, higher statistically significant values for Ctrl 0.68 (0.27), while for Rz parameter, the highest values were observed for Ctrl 4.43(1.53) and Aut 2.24 (0.62). Surface topography analysis showed that none aging method promoted surface alterations when compared to control group. Phase transformation analysis showed that all aging methods promoted an increase in m-phase content (Ctrl: 0.94%, Dist Water: 20.73%, MC: 9.47%, Aut: 53.33% and Aut+MC: 61.91%). Weibull Analysis showed higher statistical characteristic strength values for Aut (1033.36MPa) and Dist Water (1053.76MPa). No aging method promoted deleterious impact either on the biaxial flexural strengths or on the structural reliabilities (Weibull moduli). Also, none of the aging methods promoted reduction of Y-TZP mechanical properties; thus the development of new methodologies and the association between mechanical stimuli and hydrothermal degradation should be considered to better understand the mechanism of low-temperature degradation.
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Affiliation(s)
- G K R Pereira
- MDS-PhD Graduate Program in Oral Science, Federal University of Santa Maria, Santa Maria, Rio Grande do Sul, Brazil.
| | - C Muller
- MDS-PhD Graduate Program in Oral Science, Federal University of Santa Maria, Santa Maria, Rio Grande do Sul, Brazil.
| | - V F Wandscher
- MDS-PhD Graduate Program in Oral Science, Federal University of Santa Maria, Santa Maria, Rio Grande do Sul, Brazil.
| | - M P Rippe
- Faculty of Odontology, Federal University of Santa Maria, Santa Maria, Rio Grande do Sul, Brazil.
| | - C J Kleverlaan
- Department of Dental Material Sciences, Academic Centre for Dentistry Amsterdam (ACTA), Universiteit van Amsterdam and Vrije Universiteit, Amsterdam, The Netherlands.
| | - L F Valandro
- Faculty of Odontology, Federal University of Santa Maria, Santa Maria, Rio Grande do Sul, Brazil.
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Baladhandayutham B, Lawson NC, Burgess JO. Fracture load of ceramic restorations after fatigue loading. J Prosthet Dent 2015; 114:266-71. [PMID: 25985741 DOI: 10.1016/j.prosdent.2015.03.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 03/04/2015] [Accepted: 03/04/2015] [Indexed: 10/23/2022]
Abstract
STATEMENT OF PROBLEM A clinician must decide what ceramic coping and veneer material to prescribe based on the amount of tooth reduction possible and the desired esthetic outcome of the restoration. PURPOSE The purpose of this in vitro study was to compare the fracture strength of monolithic and bilayered lithium disilicate (IPS e.max) and zirconia (LAVA) crowns at clinically relevant thicknesses after load cycling. MATERIAL AND METHODS Crowns (n=8) were fabricated from 6 groups: 1.2-mm monolithic lithium disilicate, 1.5-mm monolithic lithium disilicate, 1.5-mm bilayered lithium disilicate with hand-layered veneer, 0.6 mm monolithic zirconia, 1.2-mm bilayered zirconia with hand-layered veneer, and 1.2-mm bilayered zirconia with milled veneer (dimension represents thickness at the occlusal pit). Crowns were cemented to identical milled resin dies with resin-modified glass ionomer cement. Cemented crowns were stored at 37°C for 24 hours and load cycled for 200,000 cycles at 25 N at a rate of 40 cycles/minute. The ultimate fracture load for each specimen was measured in a universal testing machine. Data were analyzed with a 1-way ANOVA and Tukey honest significant difference post hoc analysis (α=.05). RESULTS Mean ±SD fracture load values were 1465 ±330 N for monolithic lithium disilicate (1.2-mm thickness) and 2027 ±365 N (1.5-mm thickness) and 1732 ±315 N for bilayered hand-veneered lithium disilicate (1.5-mm thickness). Fracture loads were 1669 ±311 N for monolithic zirconia crowns (0.6mm thickness), 2625 ±300 N for zirconia milled-veneered (1.2-mm thickness), and 2655 ±590N for zirconia hand-veneered crowns (1.2mm thickness). One-way ANOVA showed a statistically significant difference among the groups (P<.01). Veneered zirconia crowns showed the highest fracture strength, 1.2-mm hand veneered zirconia was similar to that of 1.5-mm monolithic zirconia, and all other groups were not statistically different. CONCLUSIONS Crowns of 1.2-mm bilayered zirconia had higher fracture loads than 0.6-mm zirconia or 1.2-mm lithium disilicate monolithic crowns.
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Affiliation(s)
| | - Nathaniel C Lawson
- Assistant Professor, Department of Biomaterials, University of Alabama at Birmingham School of Dentistry, Birmingham, Ala.
| | - John O Burgess
- Professor, Division of Biomaterials, University of Alabama at Birmingham School of Dentistry, Birmingham, Ala
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12
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Effect of low-temperature aging on the mechanical behavior of ground Y-TZP. J Mech Behav Biomed Mater 2015; 45:183-92. [DOI: 10.1016/j.jmbbm.2014.12.009] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 12/02/2014] [Accepted: 12/08/2014] [Indexed: 01/24/2023]
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Otani A, Amaral M, May LG, Cesar PF, Valandro LF. A critical evaluation of bond strength tests for the assessment of bonding to Y-TZP. Dent Mater 2015; 31:648-56. [PMID: 25858783 DOI: 10.1016/j.dental.2015.03.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 05/29/2014] [Accepted: 03/05/2015] [Indexed: 10/23/2022]
Abstract
OBJECTIVES To compare three different designs for measuring the bond strength between Y-TZP ceramic and a composite material, before and after ceramic surface treatment, evaluating the influence of the size of the adhesive interface for each design. METHODS 'Macro' tensile, microtensile, 'macro' shear, microshear, 'macro' push-out, and micropush-out tests were carried out. Two Y-TZP surface treatments were evaluated: silanization (sil) and tribochemical silica coating (30μm silica-modified Al2O3 particles+silanization) (TBS). Failure mode analysis of tested samples was also performed. RESULTS Both the surface treatment and the size of the bonded interface significantly affected the results (p=0.00). Regardless of the type of surface treatment, the microtensile and microshear tests had higher values than their equivalent "macro" tests. However, the push-out test showed the highest values for the "macro" test. The tensile tests showed the greatest variability in results. The tribochemical silica coating method significantly increased bond strength for all tests. SIGNIFICANCE Different test designs can change the outcome for Y-TZP/cement interfaces, in terms of mean values and reliability (variability). The 'micro' tests expressed higher bond strengths than their equivalent 'macro' tests, with the exception of the push-out test (macro>micro).
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Affiliation(s)
- Aline Otani
- Prosthodontics Unit, Faculty of Odontology, Federal University of Santa Maria, Santa Maria, Brazil
| | - Marina Amaral
- Science and Technology Institute, São Jose dos Campos Dental School, São Paulo State University, Brazil
| | - Liliana G May
- Prosthodontics Unit, Faculty of Odontology, Federal University of Santa Maria, Santa Maria, Brazil
| | - Paulo F Cesar
- Department of Biomaterials and Oral Biology, University of Sao Paulo, Sao Paulo, Brazil
| | - Luiz Felipe Valandro
- Prosthodontics Unit, Faculty of Odontology, Federal University of Santa Maria, Santa Maria, Brazil; Science and Technology Institute, São Jose dos Campos Dental School, São Paulo State University, Brazil.
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14
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Cotes C, Arata A, Melo RM, Bottino MA, Machado JPB, Souza ROA. Effects of aging procedures on the topographic surface, structural stability, and mechanical strength of a ZrO2-based dental ceramic. Dent Mater 2014; 30:e396-404. [PMID: 25244926 DOI: 10.1016/j.dental.2014.08.380] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Revised: 02/13/2014] [Accepted: 08/29/2014] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To determine the effects of different aging methods on the degradation and flexural strength of yttria-stabilized tetragonal zirconia (Y-TZP) METHODS: Sixty disc-shaped specimens (∅, 12mm; thickness, 1.6mm) of zirconia (Vita InCeram 2000 YZ Cubes, VITA Zahnfabrik) were prepared (ISO 6872) and randomly divided into five groups, according to the aging procedures (n=10): (C) control; (M) mechanical cycling (15,000,000 cycles/3.8Hz/200N); (T) thermal cycling (6,000 cycles/5-55°C/30s); (TM) thermomechanical cycling (1,200,000 cycles/3.8Hz/200N with temperature range from 5°C to 55°C for 60s each); (AUT) 12h in autoclave at 134°C/2bars; and (STO) storage in distilled water (37°C/400 days). After the aging procedures, the monoclinic phase percentages were evaluated by X-ray diffraction (XRD), and topographic surface analysis was performed by 3D profilometry. The specimens were then subjected to biaxial flexure testing (1mm/min, load 100kgf, in water). The biaxial flexural strength data (MPa) were analyzed by 1-way ANOVA and Tukey's test (α=0.05). The data for monoclinic phase percentage and profilometry (Ra) were analyzed by Kruskal-Wallis and Dunn's tests. RESULTS ANOVA revealed that flexural strength was affected by the aging procedures (p=0.002). The M (781.6MPa) and TM (771.3MPa) groups presented lower values of flexural strength than did C (955MPa), AUT (955.8MPa), T (960.8MPa) and STO (910.4MPa). The monoclinic phase percentage was significantly higher only for STO (12.22%) and AUT (29.97%) when compared with that of the control group (Kruskal-Wallis test, p=0.004). In addition, the surface roughnesses were similar among the groups (p=0.165). SIGNIFICANCE Water storage for 400 days and autoclave aging procedures induced higher phase transformation from tetragonal to monoclinic; however, they did not affect the flexural strength of Y-TZP ceramic, which decreased only after mechanical and thermomechanical cycling.
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Affiliation(s)
- Caroline Cotes
- Department of Dental Materials and Prosthodontics, São José dos Campos Dental School, Institute of Science and Technology, UNESP-Universidade Estadual Paulista, São José dos Campos, São Paulo, Brazil
| | - Anelyse Arata
- Department of Dental Materials and Prosthodontics, São José dos Campos Dental School, Institute of Science and Technology, UNESP-Universidade Estadual Paulista, São José dos Campos, São Paulo, Brazil
| | - Renata M Melo
- Department of Dental Materials and Prosthodontics, São José dos Campos Dental School, Institute of Science and Technology, UNESP-Universidade Estadual Paulista, São José dos Campos, São Paulo, Brazil
| | - Marco A Bottino
- Department of Dental Materials and Prosthodontics, São José dos Campos Dental School, Institute of Science and Technology, UNESP-Universidade Estadual Paulista, São José dos Campos, São Paulo, Brazil
| | - João P B Machado
- National Institute of Spatial Researchs-INPE/LAS, São José dos Campos, São Paulo, Brazil
| | - Rodrigo O A Souza
- Department of Dentistry, Prosthodontics Unit, Federal University of Rio Grande do Norte (UFRN), Natal/RN, Brazil.
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15
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Bankoğlu Güngör M, Yılmaz H, Aydın C, Karakoca Nemli S, Turhan Bal B, Tıraş T. Biaxial flexural strength and phase transformation of Ce-TZP/Al2O3 and Y-TZP core materials after thermocycling and mechanical loading. J Adv Prosthodont 2014; 6:224-32. [PMID: 25006387 PMCID: PMC4085247 DOI: 10.4047/jap.2014.6.3.224] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Revised: 04/30/2014] [Accepted: 05/07/2014] [Indexed: 11/08/2022] Open
Abstract
PURPOSE The purpose of the present study was to evaluate the effect of thermocycling and mechanical loading on the biaxial flexural strength and the phase transformation of one Ce-TZP/Al2O3 and two Y-TZP core materials. MATERIALS AND METHODS Thirty disc-shaped specimens were obtained from each material. The specimens were randomly divided into three groups (control, thermocycled, and mechanically loaded). Thermocycling was subjected in distilled water for 10000 cycles. Mechanical loading was subjected with 200 N loads at a frequency of 2 Hz for 100000 times. The mean biaxial flexural strength and phase transformation of the specimens were tested. The Weibull modulus, characteristic strength, 10%, 5% and 1% probabilities of failure were calculated using the biaxial flexural strength data. RESULTS The characteristic strengths of Ce-TZP/Al2O3 specimens were significantly higher in all groups compared with the other tested materials (P<.001). Statistical results of X-ray diffraction showed that thermocycling and mechanical loading did not affect the monoclinic phase content of the materials. According to Raman spectroscopy results, at the same point and the same material, mechanical loading significantly affected the phase fraction of all materials (P<.05). CONCLUSION It was concluded that thermocycling and mechanical loading did not show negative effect on the mean biaxial strength of the tested materials.
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Affiliation(s)
| | - Handan Yılmaz
- Department of Prosthodontics, Faculty of Dentistry, Gazi University, Ankara, Turkey
| | - Cemal Aydın
- Department of Prosthodontics, Faculty of Dentistry, Gazi University, Ankara, Turkey
| | - Seçil Karakoca Nemli
- Department of Prosthodontics, Faculty of Dentistry, Gazi University, Ankara, Turkey
| | - Bilge Turhan Bal
- Department of Prosthodontics, Faculty of Dentistry, Gazi University, Ankara, Turkey
| | - Tülay Tıraş
- Department of Physics, Faculty of Science, Anadolu University, Eskişehir, Turkey
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16
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Passos SP, Nychka JA, Major P, Linke B, Flores-Mir C. In vitro fracture toughness of commercial Y-TZP ceramics: a systematic review. J Prosthodont 2014; 24:1-11. [PMID: 24975460 DOI: 10.1111/jopr.12179] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/13/2013] [Indexed: 02/04/2023] Open
Abstract
PURPOSE The aim of this review was to assess research methods used to determine the fracture toughness of Y-TZP ceramics in order to systematically evaluate the accuracy of each method with regard to potential influencing factors. MATERIALS AND METHODS Six databases were searched for studies up to April 2013. The terms "tough*," "critical stress intensity factor," "zirconi*," "yttri*," "dent*," "zirconia," "zirconium," and "stress" were searched. Titles and abstracts were screened, and literature that fulfilled the inclusion criteria was selected for a full-text reading. Test conditions with potential influence on fracture toughness were extracted from each study. RESULTS Ten laboratory studies met the inclusion criteria. There was a significant variation in relation to test method, ambient conditions, applied/indentation load, number of specimens, and geometry and dimension of the specimen. The results were incomparable due to high variability and missing information. Therefore, 10 parameters were listed to be followed to standardize future studies. CONCLUSIONS A wide variation in research methods affected the fracture toughness reported for Y-TZP ceramics among the selected studies; single-edge-precracked beam and chevron-notched-beam seem to be the most recommended methods to determine Y-TZP fracture toughness; the indentation methods have several limitations. CLINICAL SIGNIFICANCE The accurate calculation of toughness values is fundamental because overestimating toughness data in a clinical situation can negatively affect the lifetime of the restoration.
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17
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Amaral M, Valandro LF, Bottino MA, Souza ROA. Low-temperature degradation of a Y-TZP ceramic after surface treatments. J Biomed Mater Res B Appl Biomater 2013; 101:1387-92. [DOI: 10.1002/jbm.b.32957] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Revised: 02/05/2013] [Accepted: 02/11/2013] [Indexed: 11/10/2022]
Affiliation(s)
- Marina Amaral
- Department of Dental Materials and Prosthodontics; Sao Paulo State University; Sao Jose dos Campos São Paulo State Brazil
| | - Luiz Felipe Valandro
- Department of Restorative Dentistry; Federal University of Santa Maria; Santa Maria Rio Grande do Sul State Brazil
| | - Marco A. Bottino
- Department of Dental Materials and Prosthodontics; Sao Paulo State University; Sao Jose dos Campos São Paulo State Brazil
| | - Rodrigo O. A. Souza
- Department of Restorative Dentistry; Federal University of Paraiba; Joao Pessoa Paraiba State Brazil
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