Effect of a decrease of interproximal overexposure of bitewing radiographs on the diagnosis of approximal caries

In bitewing radiographs the approximal enamel is always overexposed because of the short X-ray beam path in this area. This expectedly leads to a deteriorated detectability of lesions. Abrogation of this overexposure by application of X-absorbing paste in the interproximal space will presumably relieve the deterioration of lesion detection. This principle is demonstrated with aluminum cylinders in which a groove simulates a lesion. The principle is also applied to a phantom head with 0.1- to 0.7-mm lesions in the bicuspids. The resulting bitewing radiographs were scored by dentists, and a lesion detection score as used before was calculated. No score improvement resulted from the relieving of overexposure. This is ascribed to the predominant role of recognition processes in the ability to detect a lesion.