In-vitro and in-vivo wear profile of composite resins.

The aim of this study was to evaluate in-vitro wear by two types of slurry of 10 commercial composite resin materials (seven hybrid and three microfilled composites). There was great variation in the in-vitro wear pattern by two types of slurry. The wear rate of microfilled composites was greater than that of hybrid composites, and a negative correlation was observed between wear rate and Knoop hardness values among all materials when hydroxyapatite slurry was used. In contrast, the wear rate of hybrid composites was greater than that of microfilled composites when abraded by green carborundum slurry. These abraded surfaces were compared with SEM micrographs of in-vivo composites surface after 4 years of service. The profile of in-vivo wear surfaces was found to be similar to that of in-vitro wear surfaces abraded with hydroxyapatite slurry.