A preliminary study of efficacy on root development of orthodontic traction for impacted maxillary central incisor in mixed dentition

Objective To evaluate the efficacy on root development of orthodontic traction for impacted maxillary central incisor in mixed dentition. Methods 9 cases of 8 to 11 years old impacted maxillary central incisor patients were treated with traction. CBCT measurement on root length, root canal wall thickness, and degree of root bending and the ratio of crown and root of the impacted teeth were implemented, and compared with the contralateral counterpart tooth. Results 9 teeth were treated to standard place. After traction, incisor root continues development, but root length is shorter than the control teeth. Crown root ratio and root wall thickness presented no significant difference compared to control teeth. Orthodontic treatment may not be able to change the original root dilaceration, and may cause new dilaceration during traction process. Conclusions Impacted maxillary central incisor after orthodontic traction can achieve satisfied clinical results, but indications for traction during mixed dentition should be carefully evaluated. Key words: impacted tooth; early orthodontic traction; CBCT