Radiographic detection of occlusal caries: effect of X-ray beam factors on diagnosis

The aim of this laboratory study was to determine whether the diagnostic potential of bite-wing radiographs in the diagnosis of occlusal caries could be improved by alteration of X-ray beam properties. Bite-wing radiographs of molar teeth with 16 sound and 32 carious occlusal surfaces were taken at conventional settings of 65 kVp, 15 mA and 0.3 s (4.5 mAs) and at 70 kVp, 10 mA and 1.0 s (10 mAs), to produce a darker overexposed film. Results showed that, although the overexposed radiograph resulted in more correct diagnosis of dentine caries, its use increased the number of false-positive diagnoses. More importantly, the experimental exposure factors would have led to an unacceptably high radiation dose to the patient with arguable diagnostic benefit. As such it cannot be recommended in any way for patient examination.