关键词: 龈下残根, 桩冠, 正畸牵引

Abstract:

Objective    To investigate the possibility of restoring the pivot crown after orthodontic traction of subgingiva residual root. Methods    Subgingival residual root （root length enough） has been cured by a complete root canal treatment，and then restored by fiber post，resin post and core. The bracket was bound to the resin core while keeping the bracket as close to the gingival as possible. Four to six teeth were bound with the brackets ， the mesiocclusion and distocclusion of the residual root（2-3 teeth on each side）. Fix a moderate length of nickel-titanium arch wire to the brackets，and the elastic deformation of arch wires was used to tract residual root. Prepare the abutment according to the requirement of pivot crown， finish post and core and prepar the crown， so that the root surface edge was completely sealed with restored crown. The repair was completed. Results    Two years later， crown restoration prosthesis remained stable and the edge of the root and crown was sealed. No loose， no percussion pain， no significant gingival hyperplasia and inflammation. Periodontal tissues were healthy. X-ray showed no apical shadow with continuous apical periodontal ligament；no bone absorption；no loss of alveolar bone；no recurrence root retraction. Periapical tissue was normal. Conclusion    Pivot crown restoration after orthodontic traction of subgingival residual root is feasible

Key words: subgingival residual root； pivot crown； orthodontic traction