Root resorption and apical breakdown during orthodontic treatment of a maxillary lateral incisor with dens invaginatus.

A 13-year-old girl was referred for endodontic treatment of a maxillary right lateral incisor with root resorption and apical radiolucency after orthodontic treatment. Radiographically the tooth had an invagination canal (Oehlers' Type III) and responded positively to pulp testing. The invagination canal extending to the lateral resorption was opened. Vital bleeding tissue was found, and the canal was cleaned and obturated. The pulp in the main root canal remained vital. The radiolucent lesion gradually decreased during the 3-year follow-up. The bone resorption seen here, despite vital tissue in the invagination canal, was probably due to osteoclastic activity caused by a low grade chronic infection, influenced by an injury-induced inflammation in the periodontium during orthodontic treatment.