Panoramic radiographs used alone were ineffective diagnostic aids in the detection of early interproximal carious lesions, particularly enamel lesions. The best radiographic survey in terms of numbers of enamel interproximal carious lesions detected was the combination of periapical plus posterior bitewing radiographs. For interproximal lesions extending through the enamel and into the dentin, all combinations except panoramic radiographs used alone showed comparable usefulness. For lesions involving the enamel and dentin, and extending half way or more from the dentinoenamel junction to the pulp, there generally were no significant differences between any of the combinations.