Diagnosis of caries progression from serial bitewings: a comparison between teachers and practitioners.

Approximal caries progression is best monitored from serial bitewing radiographs but the factors influencing dentists' interpretation of these films is poorly understood. Three radiographic tests were shown to a non-randomised group of 28 practitioners (GDPs) and 21 (predominantly part-time) teachers of conservative dentistry. Test 1 investigated an appreciation of the effects of irradiation geometry change on radiolucency depth. Test 2 detected evidence of irradiation geometry change from approximal overlaps and using this as a validity check for comparing serial films. Test 3 was designed to compare the effect of lack of radiolucency progression on the prescription of restorations. The results showed that in test 1, 43% of GDPs and 29% of teachers, despite being told of irradiation geometry changes, ignored the unreliability of the radiolucencies and recommended restorations. In test 2, 54% of GDPs and 71% of teachers ignored evidence of irradiation change. In test 3, 75% of GDPs and 76% of teachers ignored radiographic evidence of static carious lesions and prescribed restorations. Statistically there was no difference in the decision making outcomes between the two groups. There is cause for concern that objective radiographic data does not appear to be used correctly by the majority of dentists in planning treatment decisions.