Clinical evaluation of six composite resins in posterior teeth

Six different composite resin restorative materials were placed in posterior Class I and Class II cavities and evaluated at one and two years after placement for colour, marginal discoloration, and wear. Wear was determined by comparison with standard models and by SEM. All materials darkened over the study period but remained an acceptable match. Marginal discoloration increased. The trend of relative wear was in accordance with predictions from fracture mechanics. Insufficient restorations in one material were available at two years for it to be included in the results. The microfine materials used in this study suffered surface damage (micro-chipping) in high stress areas, again consistent with fracture mechanics predictions.