正畸牵引治疗埋伏倒置阻生的上中切牙的受力分析

The mechanics analysis of orthodontic treatment for the impacted inversed upper central incisor

目的:通过对无萌出能力的埋伏倒置阻生上中切牙正畸牵引治疗的受力分析,探讨倒置阻生上中切牙正畸牵引治疗的最佳方法。方法:对19颗无萌出能力上颌埋伏倒置阻生牙作牵引治疗前的受力分析,进行摄片定位、拓展间隙后,行外科开窗术+正畸牵引治疗。结果:19颗埋伏牙中,治疗成功13颗(占68.4%),一般4颗(占21.1%),失败2颗(占10.5%);19颗埋伏牙平均破龈时间为6.5个月,最长12个月,最短3个月;19颗埋伏牙牙髓活力测验全部正常,未见根吸收、黏连。2颗唇侧出现2mm和3mm的牙龈退缩,1颗出现1mm的边缘骨丧失,1颗未能完全进入相应的牙位,需以后配合光固化或烤瓷再度修复。1例因牙根严重弯曲,不能进入相应的牙位,被迫拔除,1例牵引3个月后萌出,因无时间复诊而放弃治疗,未排齐,其余均牵引入列。结论:准确的定位、恰当的牵引方向和位置、适当的牵引力将直接决定埋伏倒置阻生牙的移动状况。

PURPOSE： 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.