The local use of vitamin D to increase the rate of orthodontic tooth movement.

The purpose of the study was to determine if the rate and amount of orthodontic tooth movement in a sample of cats could be enhanced by the injection of a vitamin D metabolite 1,25-dihydroxycholecalciferol (1,25D) into the periodontal ligament. After 21 days of canine retraction with a light-wire retraction spring, the teeth that had received weekly intraligamentous injections of a solution of 1,25D in dimethylsulfoxide (DMSO) had moved 60% further than matched control teeth (P less than 0.05). At the histologic level, increased numbers of mononuclear osteoclasts were recruited and activated, resulting in greater amounts of alveolar bone resorption on the pressure side of the periodontal ligament. No obvious clinical, microscopic, or biochemical side effects were noted.