For composite resin and ceramic inlays there is little information about the survival of the luting agent. The purpose of this in vitro study was to relate the wear rate of the composite resin luting agent to interfacial gap dimensions and filler particle size. By controlling the gap dimension between the inlay and cavity preparation through use of computer-aided design and manufacture, a relationship was established between wear of the cement and horizontal gap width. It was confirmed that this relationship was linear. In addition, the inclination of the regression line was assumed to indicate the extent of wear. Therefore, the wear resistance of cements could be determined by determining this inclination. The results of this study revealed that ttwo hybrid cements exhibited lower wear resistance than did a microfilled cement.