The aim of this study was to assess the accuracy in predicting future development of approximal dentin lesions using radiographically observed numbers of restored and carious surfaces at age 13 as diagnostic criteria. ROC curve technique was applied employing the development of at least one new dentin lesion from age 13 to age 15 and 18 respectively, as validating criterion. Two groups of patients were considered, residing in communities with water fluoride content of 0.2 ppm and 1.2 ppm, respectively. Results showed that the development of dentin lesions could be predicted with an accuracy similar to that of many other dental radiographic procedures. This implies that it ought to be possible to use previous caries experience as a means of individualizing the scheduling of future radiographic procedures.