[Root reactions during treatment with indomethacin in the rat]

During the course of a study on the effect of indomethacin, an inhibitor of PG-synthesis, on the alveolar bone remodeling associated with the drift of the rat molar, the root profile appeared altered. The perimeter of the buccal root of the lower first molar had increased during the 7-day experimental period (+9%; p less than 0.02) in the treated group. This was due to an increase in the extent of root resorption lacunae (+99%; p less than 0.05). They were located in the disto-buccal aspect of the root, i.e., facing the alveolar wall remodeling area. The periodontal ligament width was also increased (p less than 0.001). This might be an adaptative process to maintain the periodontal ligament width as the drift of the teeth had not ceased while the remodeling had markedly slowed down. These results show that the osteoclastic population responsible for root resorption was not PG-dependent, unlike that active on alveolar wall. In addition, dentin deposition was accelerated in the pulp area underlying the resorption lacunae in the treated group as shown by measuring the distance between two fluorescent labels incorporated in a 6-day interval (p less than 0.05).