To estimate mandibular bone mass, we measured the modified Benson's Panoramic Mandibular Index (C-PMI) and the mandibular cortical width at the mental region (MCW) in panoramic radiographs.
The coefficient of variation on positioning and operator error was estimated at less than 3%.
Panoramic radiographs of 269 patients, whose premolar areas were not affected by either inflammation or some other diseases, and whose mental foramen could be confirmed on one or both sides, were selected from 626 consecutive panoramic radiographs.
Of 269 panoramic radiographs, bilateral mental foramina were visible on 124. Both in C-PMI and MCW, there was a high correlation between the two sides. The relationship between age and the C-PMI in 99 males indicated that the C-PMI increased rapidly in the 3rd dacade of life and then gradually decreased. The relationship between age and the C-PMI in 170 females indicated that the C-PMI increased gradually until the 6th decade of life and then decreased. The MCW showed a similar tendency.
