This in vitro study evaluated the wear effects of five posterior denture tooth materials on human enamel. The tooth specimen was cusp shaped and enamel specimen was formed as a 10 C 10 C 5 mm plate. All material-enamel combinations were tested using a machine designed to produce sliding contact 20 C 104 times at 60 cycles min-1 and a 4-mm sliding distance per stroke in the bucco-lingual direction under a load of 1 kg. Wear analysis was measured as the total height loss of each combination. In addition, the surface roughness (Ra) of each worn specimen was also evaluated. The least total height loss occurred with poly (methyl methacrylate) (PMMA) enamel pair, and the greatest did with porcelain (Po)-enamel pair. The lowest compound Ra value was measured in high-strength resin (HR)-enamel pair, and the highest in Po-enamel pair. These findings suggest that the best combination is PMMA-enamel, and the poorest combination is Po-enamel.