The use of panoramic radiographs to measure alveolar bone areas.

The purpose of the study was to determine the accuracy of measurements made of the mandible from panoramic radiographs. A comparison was made between measurements made directly from dry mandibles, and measurements made from panoramic radiographs of the same mandibles. The use of linear proportions reduced the errors of successive radiographic observations but failed to reveal left- and right-side differences. A method was developed to demarcate two areas of the radiograph, one of which was defined by the crest of the residual alveolar ridge and the other independent of the alveolar ridge. Both areas were measured and their proportions calculated for each mandible observed. This proportional value was referred to as the Area Index. The method was applied to panoramic radiographs of individuals with complete dentitions. The inter-observation error of the Area Index was found to be 4.9%. It was concluded that, in selected cases, panoramic radiographs can be used to provide information about resorption of the residual mandibular alveolar bone.