Progression of proximal caries in primary teeth in relation to radiographic scoring codes

The posterior bitewing radiographs of 50 children from a Duraphat clinical trial were re-examined to compare the information provided on progression of caries of two scoring systems, that of Murray & Majid (1) and that of Pitts (2). Pitts' scoring system (Method 1), by recording the disease process at an earlier stage, and by avoiding the unnecessary loss of data, provided a more complete overall picture of the carious process than the scoring system used by Murray & Majid (Method 2). The progression rates were found to be significantly faster with Method 2 (P less than 0.05). With Method 1, a mean of 60% of enamel lesions per subject had remained confined to enamel 12 months later, the corresponding figure for Method 2 was 37%. Method 2, by excluding outer enamel lesions and overlapped surfaces, introduces biases which favour overestimating the proportion of lesions deemed to have progressed. The diagnostic criteria used by Murray & Majid lead to an overestimation of the rate of progression of caries in primary teeth.