RESTORATION DETERIORATION RELATED TO LATER FAILURE

The purpose of this study was to determine the relationship between th e deterioration and the later failure of a very large number of amalga ms and anterior resin composites examined over periods of up to 16 yea rs. Assessments were made of the deterioration of various clinical fac tors or characteristics of the restorative materials that were thought to predict later failures. True failures, which were directly related to the restorative materials, accounted for 7.5% of the amalgam and 3 0.4% of the composite restorations. For the amalgams, there was a sign ificant association found between the failures and surface tarnishing. Marginal fracture and marginal staining were not associated significa ntly with any of the three different failure modes. For the composites there were significant associations found between the failures and su rface roughness, marginal fracture, and color mismatch. Surface staini ng and marginal staining were not associated significantly with any of the three different failure modes. Many restorations assessed as bein g unsatisfactory continued to function for a further 2.5 to 3.5 years on average before being replaced, often for unrelated reasons. There i s a need to define unsatisfactory restorations more clearly in terms o f actual adverse effects on dental health, rather than merely in terms of restoration deterioration.