Department of Orthodontics, University of Washington, Seattle, WA, USA.
Am J Orthod Dentofacial Orthop. 2010 Feb;137(2):158.e1-; discussion 158-9. doi: 10.1016/j.ajodo.2009.08.024.
Orthodontic space opening during adolescence is a common treatment for congenitally missing maxillary lateral incisors. Because of continued facial growth and compensatory tooth eruption, several years can elapse between completion of orthodontic treatment for a teenage patient and implant placement. There are reports that, after successful orthodontic opening of the implant space, the central incisor and canine roots reapproximate during retention and prevent implant placement.
To study this phenomenon, the records of 94 patients with missing maxillary lateral incisors were collected. Periapical and panoramic radiographs were used to measure intercoronal and interradicular distances between the central incisor and the canine adjacent to the missing lateral incisor before and after orthodontic treatment and at implant placement.
Although root approximation between the adjacent central incisor and canine during retention did not occur consistently, 11% of the patients experienced relapse significant enough to prevent implant placement.
To ensure sufficient space for implant placement, we recommend at least 6.3 mm of intercoronal space and 5.7 mm of interradicular space between the adjacent central incisor and canine. A bonded wire or resin-bonded bridge will help to reduce root approximation that might occur during retention.
青少年时期的正畸间隙打开是治疗先天性上颌侧切牙缺失的常见方法。由于面部生长和牙齿代偿性萌出的持续,青少年患者完成正畸治疗和植入物放置之间可能会相隔数年。有报道称,在成功进行正畸间隙打开后,在保持期内中切牙和犬牙的牙根会重新接近,从而妨碍植入物的放置。
为了研究这一现象,收集了 94 例上颌侧切牙缺失患者的记录。使用根尖片和全景片在正畸治疗前后和植入物放置时测量缺失侧切牙相邻的中切牙和犬牙之间的冠状和根间距离。
尽管在保持期相邻中切牙和犬牙之间的牙根接近并不总是发生,但 11%的患者出现了足以妨碍植入物放置的复发。
为了确保植入物放置有足够的空间,我们建议相邻中切牙和犬牙之间至少要有 6.3 毫米的冠状空间和 5.7 毫米的根间空间。固定的金属丝或树脂粘结桥有助于减少在保持期可能发生的牙根接近。