A study of the height of intact alveolar bone on panoramic radiographs of adult patients.

This study describes a method of estimating alveolar bone height on panoramic radiographs by using constant anatomic landmarks as reference points and calculating ratios of given distances between certain of these landmarks in dentate patients with no radiographic evidence of horizontal bone loss. Measurements were performed on four different types of panoramic radiographs. Results determined for the maxillae and mandible were constant between the different types of panoramic films. Because of differences in the measurements obtained on the right and left sides on Panorex films that have been trimmed and spliced to remove anatomic overlap in the midline areas, this type of projection may not be suitable for analysis of the maxillary alveolar bone as described in this study. The use of the mental foramen as a constant anatomic landmark for analysis of mandibular alveolar bone on panoramic radiographs may not be feasible since it appears that it may not be possible to consistently determine the exact location of the foramen. The results of the present study suggest a difference of as much as 25% among patients in the same ratio in the maxillae and as much as 12% in the same ratio in the mandible. Therefore, the results may not be of significant value as "baseline" data to estimate alveolar bone loss at a given time after tooth loss. However, this method could prove valuable in serial studies where alveolar bone height for a single patient is compared at different times before and after tooth loss.