Orthodontic external root resorption--endodontic considerations.

External root resorption in posttreatment orthodontic patients, if severe, may jeopardize the retention of the tooth or teeth involved. Numerous studies (1-5) have been undertaken to determine the relationship between the frequency and severity of external root resorption and orthodontic movement. Some investigators found the incidence of root resorption to be low (6-9), while others found it to be much higher (10, 11). The general conclusion is that external root resorption occurs in nearly all patients undergoing the forces that accompany orthodontic treatment. In recent years the use of calcium hydroxide pastes to inhibit inflammatory external root resorption has become an accepted treatment modality. Heithersay (12) and Andreasen (13) have shown that filling the instrumented root canal with calcium hydroxide can inhibit inflammatory resorptive processes. Burke (14) and Cvek (15) described the arrest of external root resorption in permanent incisors by using calcium hydroxide. These investigations suggest that calcium hydroxide has useful application in the management of a range of endodontic problems. This case is of interest because a patient presented with a chief complaint of extreme mobility of the maxillary incisors. Upon examination of sequential periapical radiographs, it was found that external apical root resorption continued after active and retentive orthodontic treatment had been terminated. A method for inhibiting external root resorption and a technique for esthetically splinting anterior teeth are described.