Fracture strength and probability of survival of narrow and extra-narrow dental implants after fatigue testing: In vitro and in silico analysis

Author(s)

Bordin, Dimorvan ; Bergamo, Edmara T. P. ; Fardin, Vinicius P. ; Coelho, Paulo G. ; Bonfante, Estevam A.

• Document type: Journal article
• Source: JOURNAL OF THE MECHANICAL BEHAVIOR OF BIOMEDICAL MATERIALS; v. 71, p. 244-249, JUL 2017.
• Web of Science Citations: 6

Abstract

Purpose: To assess the probability of survival (reliability) and failure modes of narrow implants with different diameters. Materials and methods: For fatigue testing, 42 implants with the same macrogeometry and internal conical connection were divided, according to diameter, as follows: narrow ((empty set)3.3x10 mm) and extra-narrow ((empty set)2.9x10 mm) (21 per group). Identical abutments were torqued to the implants and standardized maxillary incisor crowns were cemented and subjected to step-stress accelerated life testing (SSALT) in water. The use level probability Weibull curves, and reliability for a mission of 50,000 and 100,000 cycles at 50 N, 100, 150 and 180 N were calculated. For the finite element analysis (FEA), two virtual models, simulating the samples tested in fatigue, were constructed. Loading at 50 N and 100 N were applied 30 degrees off-axis at the crown. The von-Mises stress was calculated for implant and abutment. Results: The beta (beta) values were: 0.67 for narrow and 1.32 for extra-narrow implants, indicating that failure rates did not increase with fatigue in the former, but more likely were associated with damage accumulation and wear-out failures in the latter. Both groups showed high reliability (up to 97.5%) at 50 and 100 N. A decreased reliability was observed for both groups at 150 and 180 N (ranging from 0 to 82.3%), but no significant difference was observed between groups. Failure predominantly involved abutment fracture for both groups. FEA at 50 N-load, (empty set)3.3 mm showed higher von-Mises stress for abutment (7.75%) and implant (2%) when compared to the (empty set)2.9 mm. Conclusions: There was no significant difference between narrow and extra-narrow implants regarding probability of survival. The failure mode was similar for both groups, restricted to abutment fracture. (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