Purpose: Restorative material selection in complete mouth rehabilitation is an important factor in long-term management of potential technical complications. The aim of this study was to evaluate in vitro the reliability (fracture resistance) of lithium disilicate fatigued with different restorative materials.
Materials and methods: A step-stress accelerated life-testing model was used. Seventy disc specimens were heat-pressed. Five groups of different indenter materials fatigued the lithium-disilicate specimens: group WC (tungsten carbide served as a control), group PR (interpenetrating polymer network [IPN] resin-based denture tooth), group POM (heat-pressed leucite glass-ceramic), group LD (heat-pressed lithium disilicate), and group ZR (zirconium dioxide). Lithium-disilicate specimens were randomly divided into four groups (n = 14). Specimens were fatigued to failure according to three step-stress profiles: light, moderate, and aggressive. Use level probability Weibull plots were generated, and each group's reliability, failure rate, and mean life to failure were calculated.
Results: The IPN resin-based denture tooth group had the highest reliability and mean life to failure, and lowest failure rate as compared to lithium disilicate and zirconium dioxide. No significant difference existed between the reliability of the tungsten carbide and leucite glass-ceramic groups and the IPN resin-based denture tooth group.
Conclusions: Lithium-disilicate specimens fatigued with IPN resin-based denture teeth exhibited higher reliability than specimens fatigued with lithium disilicate and zirconium dioxide. There was a difference in fracture characteristics in lithium-disilicate specimens fatigued with tungsten carbide, lithium disilicate, and zirconium dioxide, versus those fatigued with IPN resin-based denture teeth and leucite glass-ceramic material.
Keywords: Lithium disilicate; denture teeth; heat-pressed ceramics; leucite glass-ceramics; zirconium dioxide.
© 2014 by the American College of Prosthodontists.