A preliminary study of wear of porcelain when subjected to functional movements of retentive clasp arms

Porcelain-metal crowns simulating abutment retainers for removable partial denture clasping were studied to determine the effects of wear to the porcelain surface and possibilities of fracture. Surface profile recordings at x 1,000 were made on the porcelain surfaces before and after subjecting samples to wear that was equivalent to 2 years of patient use. Little or no change was recorded in these surface profiles, indicating that little or no wear had occurred. None of the samples failed due to porcelain fracture. It appears that well-fabricated, glazed porcelain surfaces can withstand the wear forces of removable partial retentive clasp arms.