Caries diagnosis within restored teeth.

Secondary caries is the most common reason given by dentists for the replacement of restorations, and yet this is a diagnosis that is difficult to make with confidence. This paper attempts to define some of the problems in the diagnosis of caries in restored teeth. The histology of the secondary carious lesion shows that it may be considered in two parts: an outer lesion adjacent to the filling, and a wall lesion which will occur only if there is leakage between the filling and the tooth. The specific diagnostic difficulties addressed are the difficulty of seeing this wall lesion, whether a defective margin indicates secondary caries, and the difficulties of differentiating secondary from residual caries and active from arrested disease. Since further research is needed to solve many of these problems, the paper ends by discussing the consequences of these difficulties for clinicians, epidemiologists, teachers, and research workers.