Stress transmission analysis and flexural strength of zirconia implants after mechanical cycling

Author(s)

Diogo Rodrigues Cruvinel

• Document type: Doctoral Thesis
• Press: Ribeirão Preto.
• Institution: Universidade de São Paulo (USP). Faculdade de Odontologia de Ribeirão Preto (PCARP/BC)
• Defense date: 2013-06-28

Examining board members

Heitor Panzeri; João Neudenir Arioli Filho; Regina Maura Fernandes; Mauro Antonio de Arruda Nóbilo; Hebert Luís Rossetto

• Advisor: Heitor Panzeri

Abstract

The aim of this study was to develop a new Zirconia (Y-TZP) and Titanium (Grade 4) implant macrostructure to make an accurate comparative evaluation of the stress transmission and flexural strength after both materials were subjected to mechanical and thermomechanical fatigue. Thirty three Zirconia and Titanium Grade 4 implants were obtained. A force of 200N was applied to the long axis of the implants and the distribution of the generated stress around implants was initially observed in three specimens by photoelastic analysis. Then, the implants were embedded in polyurethane resin (F-16, AXSON Technologies) with an inclination of 30°and randomly divided into groups (n = 10), according to the type of treatment they were subjected to: Control (no treatment ) (Zr and Ti), mechanical fatigue (ZRM and TiM) and thermomechanical fatigue (ZrTM and TiTM). The mechanical fatigue testing machine was programmed to apply a load of 133 N, with a frequency of 120 cycles per minute (2 Hz) and a total of 2,000,000 cycles in each specimen. The thermocycling was set with the minimum temperature between 2°-5°C and maximum temperature between 50°-55°C with 30 seconds exposure for each track and 5 seconds for the exchange of fluids. Following the fatigue test (chewing simulation), all groups were subjected to flexural strength test. The data were subjected to statistical analysis (2-way ANOVA, Bonferroni test, p <0.05) and the results showed no statistically significant difference between Zirconia and Titanium implants\'s stress transmission values. Titanium implants showed higher flexural strength, which was statistically significant (p <0.05) compared with Zirconia implants. It was concluded that it was possible to obtain a Zirconia implant design compatible with the forces applied in the oral environment. Moreover, the mechanical and thermomechanical fatigue had no influence on the flexural strength of both Titanium and Zirconia implants. (AU)

• FAPESP's process: 10/12072-8 - Stress analysis and flexural strength of zirconia implants after mechanical cycling
• Grantee: Diogo Rodrigues Cruvinel
• Support Opportunities: Scholarships in Brazil - Doctorate