[Quantitative study on the effects of parathyroidectomy on the osseous remodelling and physiological migration of teeth in the rat].
Numerous hypotheses have been advanced to explain the factors determining the rhythm and direction of the physiological drift of the teeth, but the exact causes of the phenomena are still poorly understood. Since dental mesial drift and alveolar bone remodeling are closely associated, the influence of the parathyroid hormone, systemic factor of bone remodeling, was studied. A cessation of physiological mesial drift was observed in 8 days on parathyroidectomized rats without the use of any direct local action or compression of the periodontal ligament, on the resorbing alveolar side. Parathyroid hormone injection in rats parathyroidectomized for 4 days allowed the development of physiological drift in the same direction. Alveolar bone is therefore parathyroid hormone dependent : the remodeling seemed to determine the physiological drift whereas a local factor seemed to determine the direction.