A reevaluation of the distribution of 3H-proline in the transseptal ligament of the mouse in radioautography.

It is generally accepted that there is uniform collagen metabolism within the periodontal and transseptal ligaments. The present study suggested regional variations in the incorporation and removal of 3H-proline within the transseptal ligament in radioautography, suggesting variable rates of collagenous protein remodeling coincident with physiological tooth movements. Highest numbers of silver grains were over the middle third of the ligament during both incorporation and removal phases (p less than 0.001). Rates of grain removal were greater in the middle than in mesial or distal thirds (p less than 0.001). The half-life of labeled proteins was significantly less in the middle than in mesial or distal thirds (p less than 0.005). Because there were no significant regional differences in cell numbers, regional variability in grain incorporation and removal within the transseptal ligament likely indicates regional differences in cellular synthetic or degradative activity coincident with remodeling of the transseptal ligament during physiological drift and suggests that the center of this ligament may experience more stress and, thus, remodels more rapidly.