WEAR-RESISTANCE OF SOME PROSTHODONTIC MATERIALS INVIVO

The purpose of this study was to compare a gravimetric method and an i mpression technique in the evaluation of occlusal substance loss. The wear of gold, porcelain, and microfilled resin was studied in vivo. Th e gravimetric method showed lower substance loss for porcelain than fo r 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 a rea has to be restricted, the antagonizing occlusal contacts carefully recorded before the test period, and the number of cuts increased. Th e observed structure of wear facets (SEM) corroborated with previous f indings of the wear mechanism of these materials; that is, gold has ma inly abrasive wear in contact with porcelain, whereas porcelain has a fatigue type and microfilled resin a tribochemical type of wear.