An in vitro investigation of the wear of enamel on porcelain and gold in saliva.

This study compared enamel wear against low-fusing porcelain (Procera All-Ceramic) with the wear against feldspathic porcelain (Ceramco) and gold alloy (Olympia). Human enamel abraders were polished to a 3 microns variance on silicon carbide paper. Five enamel abraders were abraded against five disks that were fabricated from (1) gold alloy polished to 1 micron variance, (2) autoglazed feldspathic porcelain, and (3) autoglazed low-fusing porcelain. The enamel sample was tested in human saliva in a wear machine with a constant load of 1 pound during 10,000 rotational cycles. The amount of wear was determined with a stereomicroscope at magnification x64. Significant differences in mean enamel wear were found when abraded against Olympia gold (9 microns), Procera All-Ceramic (60 microns), and Ceramco feldspathic porcelain (230 microns). Significant differences in restorative material wear were found between Olympia gold (0.32 microns) and the porcelain materials, Procera All-Ceramic (4.3 microns) and Ceramco feldspathic porcelain (3.7 microns).