Optical quantitation and radiographic diagnosis of incipient approximal caries lesions.

The objectives of this study were to test the applicability of photocell measurements in approximal caries diagnosis and to evaluate the use of radiographs as validating criterion. Forty extracted premolars were selected, and the progression of the approximal lesions was graded clinically and radiographically by three examiners. Each tooth was transilluminated from the occlusal surface, and the throughput of light at the approximal surface was measured by a photocell. Together with clinical examination, the results of microradiographic analysis served as validating criterion in this study. The results indicate that photocell measurements can be useful in the diagnosis of incipient approximal caries lesions. Radiographs have a restricted value as validating criterion in diagnostic studies pertaining to incipient caries.