Study of the flexural strength of the lithium disilicate glass ceramic for use as a dental prosthesis

Abstract

Dental materials are often targeted in research because patients are becaming aware of aesthetics such as facets. As regards to ceramic prostheses, those made of litium dissilicate (glass-ceramics, GC) allow the combination of high fracture resistance with excellent aesthetics due to their high translucency, being very similar to natural teeth. The best commercial materials have a strength of about 400 MPa, but the research work of Wolfram Hoeland shows values of 740 + 1,80 MPa showing that is possible to improve it. In the doctorate work of Dr. Mariana O. C. Villas Bôas (in our lab) she developed two types of GC materials, one for injection molding and other for CAD/CAM. These prostheses have been evaluated by various techniques, missing only the part of mechanical strength. Then the objective of this project is to evaluate the biaxial flexural strength according to DIN EN ISO 6872 of those two types of materials. We will also evaluate, for comparison, the commercial prostheses e-max Press and e-max CAD - the best prostheses on the market. Moreover, we will study how the processing variables, residual stresses, surface finish and the actual testing dispositive interfere in the final properties. After the tests, the sample fractures will be observed and the results will be analysed with the Weibull statistical method. (AU)