Alveolar bone mass using 125I absorptiometry.

Small changes in alveolar bone mass are very difficult to detect using radiograms. A method is described for registering minute changes in bone mass in restricted parts of the jaw. The method is based on the use of collimated monenergetic radiation from 125I and replacement of the roentgen film by a non-image forming detector. As the apparatus also can be used for measuring the object thickness, the attenuation formula can be used for calculating the alveolar bone mass. The radiation dose can be kept an extremely low level and the reproducibility of the measurements is high. The technique therefore may be used for long-term studies of changes in alveolar bone mass. The alveolar bone mass responds rapidly to changes in the neighboring tissues. The reaction following gingivectomy or dental trauma is characterized by a significant loss of alveolar bone mass initially. After 4 weeks an increase in the alveolar bone mass is noted and found to continue during the subsequent months.