[The mechanics analysis of orthodontic treatment for the impacted inversed upper central incisor].
OBJECTIVE
To study the treatment on the impacted inversed upper teeth by orthodontic traction.


METHODS
Nineteen impacted curved upper teeth were treated with surgical exposure and orthodontic traction after X-ray location and tooth space expansion.


RESULTS
Among the 19 impacted teeth, thirteen teeth were successfully treated, four were approximately erupted, two were failed. The average eruption time of the 19 impacted teeth was 6.5 months(3-12 months). All the teeth had vital pulp without root absorption or conglutination. There was labial gingival regression with 2mm and 4mm in 2 teeth, respectively. Marginal bone loss of 1.0 mm was found in one tooth. In 1 case, the tooth couldn't be moved into alignment, and light-cured or porcelain crown treatment was suggested. In 1 case, the tooth couldn't be moved into alignment due to the severely curved root, and then was extracted. In 1 case, the tooth erupted after traction for 3 months, but the patient rejected the treatment. All the other teeth moved into alignment.


CONCLUSIONS
Exact location, appropriate traction force and direction decide the movement of impacted teeth.
Wang
Sun
S
Department of Preventive & Pediatric Dentistry, College of Stomatology, Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
Shen
Yong-Qin
YQ
Feng
Xi-Ping
XP
D003442:Crowns; D006801:Humans; D007180:Incisor; D009967:Orthodontic Appliances; D014078:Tooth Eruption; D014095:Tooth, Impacted