The need for polishing and occlusal adjustment of zirconia prostheses for wear on antagonist teeth.

The attrition of enamel when opposed by ceramics is of great concern. The purpose of this study was to evaluate enamel wear against high translucent zirconia (Zr), lithium disilicate (LD), gold (Au), and enamel (E) with different surface and contact conditions. The materials were divided into two groups: polished and ground (n=8 each). Two-body wear tests were performed against human enamel with vertical and horizontal, horizontal, and vertical repetitive movements as experiments 1 to 3 respectively. The surface roughness of all materials except Zr changed throughout the experiments. In experiment 1, Zr and Au showed less antagonist wear when polished than when ground. In experiment 2, polished groups showed less antagonist wear than ground groups in all materials. In experiment 3, Zr and LD exerted greater antagonist wear than E, regardless of Ra. These findings confirm the importance of polishing and occlusal adjustment of zirconia.