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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Implant-abutment fit influences the mechanical performance of single-crown prostheses

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Author(s):
Ramalho, Ilana S. [1] ; Bergamo, Edmara T. P. [1] ; Witek, Lukasz [2] ; Coelho, Paulo G. [2] ; Lopes, Adolfo C. O. [1] ; Bonfante, Estevam A. [1]
Total Authors: 6
Affiliation:
[1] Univ Sao Paulo, Dept Prosthodont & Periodontol, Bauru Sch Dent, Bauru, SP - Brazil
[2] NYU, Dept Biomat & Biomimet, New York, NY - USA
Total Affiliations: 2
Document type: Journal article
Source: JOURNAL OF THE MECHANICAL BEHAVIOR OF BIOMEDICAL MATERIALS; v. 102, FEB 2020.
Web of Science Citations: 0
Abstract

Objectives: To evaluate the three-dimensional fit of abutments fabricated by the industry to those either milled or cast by a commercial laboratory and to correlate the implant-abutment connection fit with stress at fatigue failure of prostheses. Probability of survival (reliability) and fractography to characterize failure modes were also performed for cemented and screw-retained prostheses. Methods: One-hundred and twenty-six maxillary central incisor crowns were milled to restore implants and divided in 3 cemented and 3 screwed-retained groups (n = 21/each), as follows: {[}Digital-Sc]: milled one-piece monolithic abutment/crown; {[}TiB-Sc]: milled crowns cemented onto Ti-base abutments; {[}UCLA]: screwretained crown using UCLA abutments; {[}Digital-Ce]: milled two-piece assembly comprised by screwed monolithic abutment and a cemented crown; {[}TiB-Ce]: milled coping cemented onto Ti-base abutments to receive a cemented crown; {[}UCLA-Ce]: UCLA abutments that received an overcast coping and a cemented crown. Implant-abutment volume misfit was assessed by micro-computed tomography using the silicone replica technique. Implant/crown systems were subjected to stepstress accelerated life testing (SSALT) in water. The use-level probability Weibull curves and reliability for a mission of 50,000 cycles at calculated stress at failure of 2,300, 3300 and 4300 MPa were plotted. Fractographic analysis was performed with scanning electron microscopy. Internal misfit was analyzed through one-way ANOVA following post-hoc comparisons by Tukey test (p < 0.05). Correlation between misfit volume and the stress at fatigue failure was assessed by Pearson test. Results: Similar misfit volumes were observed for TiB-Sc (0.458 mm(3)), TiB-Ce (0.461 mm(3)), UCLA (0.471 mm(3)) and UCLA-Ce (0.480 mm(3)), which were significantly lower than Digital-Sc (0.676 mm(3)) and Digital-Ce (0.633 mm(3)). The mean beta values were: 1.68, 1.39, 1.48, 2.41, 2.27 and 0.71 for Digital-Sc, TiB-Sc, UCLA, Digital-Ce, TiB-Ce and UCLA-Ce, respectively, indicating that fatigue was an accelerating factor for failure of all groups. Higher stress at failure decreased the reliability of all groups, more significantly for screw compared to cement-retained groups, especially for Digital-Sc that demonstrated the lowest reliability. The failure mode was restricted to abutment screw fracture. A negative correlation was observed between misfit values and stress at failure (r = -0.302, p = 0.01). Conclusions: Abutments milled by a commercial lab presented higher misfit compared to those provided by the industry and a moderate correlation was observed between higher misfit and lower stress at failure during fatigue. Probability of survival decreased at higher stress, especially for screw compared to cement-retained groups, and failures were confined to abutment screws. (AU)

FAPESP's process: 12/19078-7 - Development and processing of Al2O3-ZrO2 translucent composite for CAD/CAM monolithic prostheses: the effect of aging on biaxial flexural strength
Grantee:Estevam Augusto Bonfante
Support Opportunities: Research Grants - Young Investigators Grants
FAPESP's process: 19/14798-0 - Development of pre-sintered ZTA 80% Al2O3/20% ZrO2 composite blocks for milling in CAD/CAM system
Grantee:Adolfo Coelho de Oliveira Lopes
Support Opportunities: Scholarships in Brazil - Doctorate
FAPESP's process: 16/17793-1 - Development and mechanical and optical characterization of 80% Al2O3 and 20% ZrO2 translucent composites for CAD/CAM monolithic prostheses
Grantee:Adolfo Coelho de Oliveira Lopes
Support Opportunities: Scholarships in Brazil - Master
FAPESP's process: 19/08693-1 - Experimental glass-infiltrated alumina-zirconia composites: characterization of microstructure, optical and mechanical properties.
Grantee:Edmara Tatiely Pedroso Bergamo
Support Opportunities: Scholarships in Brazil - Post-Doctoral
FAPESP's process: 16/18818-8 - Multi-User Equipment approved in grant 2012/19078-7: ElectroPuls E3000 Linear-Torsion All-Electric dynamic test instrument package
Grantee:Estevam Augusto Bonfante
Support Opportunities: Multi-user Equipment Program