Comparison of the fatigue parameters of dental ceramics obtained by different test methods

• Grant number: 14/02247-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: May 01, 2014
• End date: April 30, 2015
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: Paulo Francisco Cesar
• Grantee: Sahar Ganz Riman
• Host Institution: Faculdade de Odontologia (FO). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The objectives of this project are: (1) To compare the stress corrosion suscebility exponent (n), obtained by cyclic fatigue and dynamic fatigue for two dental ceramics: Yttria partially stabilized tetragonal zirconia polycrystal (Y-TZP) and a feldspathic porcelain (VM). (2) To verify the existence of R curve behavior for the studied materials and correlate these results with the n values obtained by the different fatigue tests. Bars with 4.0 x 3.0 x 26 mm of each material will be produced following the manufacturers' specifications. For each experimental group the slow crack growth (SCG) parameters will be obtained by cyclic fatigue (n=10) and by dynamic fatigue (n=80) using a four point bending fixture. The R curve behavior will be tested for each material (n=10). The fracture surfaces will be observed in optical and scanning electron microscope (SEM). The SCG parameters obtained from the dynamic fatigue test will be calculated using the formulas shown in ASTM C 1368-00. The SCG parameters obtained by cyclic fatigue will be determined by Weibull statistics. The existence of R curve behavior for all materials will be determined after the construction of a graph of the log of the fracture strength as a function of the log of the indentation load obtained by the R curve test. (AU)