Microabrasion of cast metal margins--a warning.

Plastic test patterns were milled to simulate casting margins and were cast in a variety of dental alloys. The cast specimens were exposed to horizontal and vertical streams of low-pressure microabrasion with 50 microm aluminum oxide particles. Post-exposure measurements show all specimens were affected by microabrasion. Dentists and laboratory technicians who use microabrasion must be aware of the potential damage to casting margins.