Previous research has shown that new technology in adhesive dentistry improves the performance of all-ceramic restorations. However, the major reason for failure of these restorations remains the occurrence of fractures. The overall objective of this research project was to investigate the influence of cement on the survival of all-ceramic restorations.
A preliminary study was performed to evaluate the influence of the cement as a supporting structure on the survival of a simulated all-ceramic restoration. A trilayer simulation of a model restoration subjected to a clinically relevant condition of functional mastication was used. The results from the preliminary study showed that adhesively bonded specimens had higher survival rates than those conventionally cemented and that one of the adhesive cements had a significant higher survival rate than the other.
Based on results from the preliminary study, three other studies were performed to investigate why adhesive cementation improves the performance of all-ceramic restorations. Results from these studies showed: (1) Resin cements had fewer defects or were void-free at the ceramic-cement interface of our ceramic model, while conventional cements showed areas of voids at the this interface. (2) The resin cement had no influence on ceramic sensitivity to slow crack growth (SCG). (3) While the actual mechanism for resin strengthening could not be determined, it may involve the formation of a more durable bond at the ceramic/cement interface.