A longitudinal radiographic study of the rate of spread of human approximal dental caries

Abstract

Ninety-six approximal initial carious lesions in 51 patients were followed up to 4 years on serial bite-wing radiographs. The average rate of spread of the lesion from the surface of the tooth up to the dentine-enamel junction was 26.4 months in the 14–15 yr-old group, and 32.3 months in the 21–24 yr-old group, the difference being significant ( p < 0.01). Less than 20 per cent of the initial lesions reached the dentine within 24 months. Twelve per cent of the initial lesions had not changed after 36 months. The “50 per cent survival time” of the initial carious lesions was 9.7 months, while it was 12.5 months for the more advanced enamel lesions. When the lesions were classified according to their morphology, it was found that 66 per cent of lesions were of triangular morphology, 16 per cent were diffused and 18 per cent were unclassifiable in shape.