Moving an ankylosed central incisor using orthodontics, surgery and distraction osteogenesis

Abstract

When a dentist replants an avulsed tooth, the repair process sometimes results in the cementum of the root and the alveolar bone fusing together, with the replanted tooth becoming ankylosed. When this occurs, the usual process of tooth movement with bone deposition and bone resorption at the periodontium cannot function. If dental ankylosis occurs in the maxillary incisor of a growing child, the ankylosed tooth also cannot move vertically with the subsequent vertical growth of the alveolar process. This results in the ankylosed tooth leaving the plane of occlusion and often becoming esthetically objectionable. This report describes a 12-year-old female with a central incisor that was replanted 5 years earlier, became ankylosed, and left the occlusal plane following subsequent normal vertical growth of the alveolar process. When growth was judged near completion, the tooth was moved back to the occlusal plane using a combination of orthodontics, surgical block osteotomy, and distraction osteogenesis to reposition the tooth at the proper vertical position in the arch. This approach had the advantage of bringing both the incisal edge and the gingival margin of the clinical crown to the proper height in the arch relative to their antimeres. Previous treatment procedures for ankylosed teeth have often involved the extraction of the affected tooth. When this is done, a vertical defect in the alveolar process results that often requires additional bone surgery to reconstruct the vertical height of the alveolar process. If the tooth is then replaced, the replacement tooth must reach from the final occlusal plane to the deficient ridge. This results in an excessively long clinical crown with a gingival height that does not match the adjacent teeth.