Statistical analysis of acoustic emissions during shrinkage of restoration in dental substrate

Abstract

Evaluation of marginal integrity at the composite resin-tooth interface is required for clinically successful restorations. Polymerization contraction of the composite resin that fills in a cavity occurs during light curing. This contraction competes with the bond strength and may cause marginal disintegration. There can be some unbonded state and/or cleavage formation around the margin of the composite resin part, leading to insufficient sealing of open dentinal tubules[1]. Various experiments such as SEM and dye penetration test[2] have been performed for observing the marginal gap along the composite resin-tooth interface. These studies did not show any temporal analysis of debonding mechanisms. The present authors investigated the fracture process of composite/tooth by an acoustic emission (AE) monitoring in real-time[3]. The AE data that was newly obtained needs to be differentiated according to various test conditions. In this study, a non-parametric statistic is applied to verify the difference of AE amplitudes and AE hits depending on substrate kinds and adhesive conditions.