Effect of the mechanical cycling on the strength of dental ceramics

• Grant number: 09/14159-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: November 01, 2009
• End date: October 31, 2010
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: Paulo Francisco Cesar
• Grantee: Vanessa Juliana Gomes Carvalho
• Host Institution: Faculdade de Odontologia (FO). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The purpose of this project is to evaluate the strength degradation of eight dental ceramics after in vitro aging simulation by mechanical cycling and to relate these results to the microstructure of each material. Two glass-infiltrated alumina composites: a) Vita In-Ceram Alumina - Vita (ICA) and b) Alglass - EDG (AG); two glass-infiltrated alumina-zirconia composites: a) Vita In-Ceram Zirconia - Vita (ICZ) and b)Vitro-Ceram - Ângelus (VC); one ytria stabilized zirconia: Vita In-Ceram 2000 YZ Cubes (Y-TZP) and one alumina polycrystal: Vita In-Ceram 2000 AL Cubes (AL) will be used. Fifty disc specimens (12 mm x 1 mm) will be prepared according to manufacturers' instructions. A control group will be tested (n=30), in which specimens will be fractured in a bi-axial flexural strength test (piston-on-three-balls). The remaining 20 specimens will be divided in two groups (n=10) which will be fractured in the same manner after being subject to two different protocols of cyclic fatigue in a chewing simulator. The cyclic fatigue will be carried out under artificial saliva at 37oC with a 2 Hz frequency. The strength results of the control group will be analyzed by the Weibull statistics and the effect of the cyclic fatigue on strength will be analyzed by ANOVA and Tukey test (alpha=0.05). (AU)