The cervical margin of amalgam restorations: a radiographic and clinical assessment.

In a study of the condition of the cervical margin of class II amalgam restorations, a radiographic method of assessment was compared with clinical assessment using mouth mirror and probe. The radiographic method assesses the type of defect of the cervical margin on the one hand, and the degree of defect on the other. In addition, an in-vitro study was performed of forty-six primary molars with multiple-surface amalgam restorations, in order to evaluate the results of the comparative study. Comparison of the results of clinical assessment with those of radiographic assessment revealed that: There is no correlation between the type of defect of the cervical margins of the amalgam restorations and their clinical assessment. There is a correlation between the degree of cervical margin defect and clinical assessment, as long as the defect does not exceed 1.5 mm. There is no significant difference between the clinical and the radiographic methods of assessment. Using both methods, only 20 percent of the cervical margins seemed to show "good" adaptation. The results of the in-vitro study warrant the conclusion that: In this study, too, only 20 percent of the cervical margins showed good adaptation. The restorations of the forty-six shed primary molars were of the same quality as those involved in the comparative study. These two conclusions warrant the postulate that, when only one of the two methods of assessment is used, the results must be divided by two in order to gain an accurate impression of the condition of the cervical margins.