A Method of Quantitative Analysis of the Edentulous Mandibular Bone Height by Rotational Panoramic Radiography

A method was devised to calculate mandibular alveolar bone height in edentulous patients from panoramic radiographs. Panoramic radiography is generally unsuitable for determing alveolar bone loss because of distortion and indeterminate magnification of the radiographs. The method utilizing five metal tubes were placed on the alveolar crest at the incisor, premolar and molar regions of three dried human mandibles. The known dimensions and the position of the tubes enabled correction for distortion and magnification to be made as well as the height of the mandibular alveolar to be calculated. The metal tubes were attached to the alveolar bone perpendicular to the mandibular plane in a position which fell within the image plane of the radiograph. The mandibular height was measured along perpendicular lines drawn through the central axis of the tubes. From the known height of the dried mandible a factor was calculated for application to the measurement from the panoramic radiographs. The errors were almost found to be less than 3-4% of the actual mandibular height. From these results it was found to be possible to calculate mandibular alveolar bone values clinically by placing the standard metal tubes on the alveolar crest of patients before exposing the panoramic radiograph.