Clinical assessments of dental amalgam restorations

In assessing the performance of amalgam restorations in most clinical studies, the significant factor to evaluate is marginal fracture. The clinical relevance of marginal fracture is reflected in its relationship to the presence of secondary caries. Furthermore, whereas most other failures can be avoided by proper operator technique, marginal fracture is an inherent deficiency of amalgam restorations. Although the extent of marginal fracture can be influenced by many factors, the nature of the alloy has been found to play a major role. However, for a properly conducted study, other factors which include the operator, patient and tooth type should be acknowledged in the research design. To evaluate marginal fracture in clinical studies, the occlusal photograph--visual assessment technique is a most sensitive method and the scoring of test restorations according to a standard set of photographs has several significant advantages.