Fatigue and stress distribution in materials for indirect partial restorations

Abstract

Several different materials are available for indirect dental restorations, and fracture is the main clinical failure mode of these restorations. The aim of this study is to evaluate the hardness, toughness, stress distribution, failure load and fatigue of indirect restoration materials bonded to a dentin-like substrate (NG10). Four restorative materials will be evaluated: indirect composite resin, lithium disilicate ceramic, feldspathic ceramic and resin-matrix ceramic. Discs (12 mm x 1,2 mm) from ceramic blocs were adhesively cemented on treated NG10 and from composite resin were build up direct on the base material. Hardness and toughness (n=5) will be measured. Stress distribution will be evaluated via finite element analysis. Load to failure will be measured in a universal testing machine (n=20), and mechanical fatigue will be performed (n=20) with 65% of the load to failure, at 4 Hz. The sample will be inspected every 200 thousand cycles for cracks, until 1x106 cycles. Data will be subjected to reliability and fatigue-life analysis. After tests, samples will be evaluated regarding failure origin. (AU)