The quality of routine class II cavity preparations for amalgam.

In spite of many improvements in operative dentistry, the incidence of replacements of amalgam restorations remains high. It is possible that specific cavity features are important for the longevity of the restorations. Six hundred and ten epoxy plastic models, made from impressions of permanent teeth in which class II cavities had been prepared by eight Scandinavian dentists, were examined. The examination showed prevalent imperfect external and internal cavity features. These may reflect the operators' opinion of adequate operative dentistry, neglect to control design features, or lack of training in examining a cavity critically.