Wear resistance of some prosthodontic materials in vivo.

The purpose of this study was to compare a gravimetric method and an impression technique in the evaluation of occlusal substance loss. The wear of gold, porcelain, and microfilled resin was studied in vivo. The gravimetric method showed lower substance loss for porcelain than for gold, whereas the microfilled resin had the highest substance loss. To obtain a higher accuracy for the measurement of occlusal substance loss of restorative materials with an impression technique, the test area has to be restricted, the antagonizing occlusal contacts carefully recorded before the test period, and the number of cuts increased. The observed structure of wear facets (SEM) corroborated with previous findings of the wear mechanism of these materials; that is, gold has mainly abrasive wear in contact with porcelain, whereas porcelain has a fatigue type and microfilled resin a tribochemical type of wear.