替牙期牵引上颌埋伏阻生中切牙的疗效观察

Evaluation of the orthodontic treatment outcome in patients with impacted maxillary central incisorin the mixed dentition

目的在替牙期对埋伏阻生的上颌中切牙进行牵引治疗，并在治疗完成后1年复查，从牙根发育、牙槽骨发育、牙周及牙髓状态四方面评价其疗效及稳定性。方法选取北京大学口腔医学院·口腔医院儿童口腔科9例8至11岁共计9颗上颌中切牙埋伏阻生患者行牵引治疗，对9颗患牙（治疗组）在牵引前、牵引结束即刻、保持1年复查时应用锥形束CT和模型分别测量牙根、牙槽骨及牙龈位置，并检查牙周状况及牙髓活力，均以对侧同名牙为对照牙（对照组）进行比较，评价治疗效果。结果9例经牵引治疗的埋伏阻生中切牙牙根均继续发育，治疗期间生长发育水平与对照牙持平；牙槽骨继续发育改建，垂直阻生的上颌中切牙牵引结束即刻牙槽骨水平及厚度优于水平阻生或存在牙根弯曲的患牙；埋伏阻生的上颌中切牙牵引结束即刻无牙周袋、牙髓坏死出现；7例患者在治疗完成后1年接受复查，对照组牙根长度为（13．07±2．15）mm，治疗组牙根长度为（12．06±2．00）mm，两组差异有统计学意义（P〈0．05）；牙槽骨骨量及牙龈位置稳定，对照组唇、腭侧牙槽骨水平分别为（0．90±0．62）、（0．45±0．52）mm，唇、腭侧牙槽骨厚度分别为（0．85±0．14）、（1．21±0．41）mm，治疗组唇、腭侧牙槽骨水平分别为（2．18±1．59）、（0．57±0．71）mm，唇、腭侧牙槽骨厚度分别为（0．48±0．29）、（1．43±0．31）mm，上述4项指标仅唇侧牙槽骨两组相比差异有统计学意义（P〈0．05），其他3项指标两组相比差异均无统计学意义（p〉0．05）；未出现牙髓坏死。结论上颌埋伏阻生中切牙经牵引矫治能促进牙根发育、牙槽骨改建，牙周及牙髓隋况良好，临床效果稳定。

Objective To evaluate the orthodontic treatment outcome in patients with impacted maxillary central incisor in the mixed dentition. Methods Nine patients, aged 8 to 11 years, with impacted maxillary central incisor were treated orthodontically. The cone-beam CT（CBCT） was taken before treatment, after treatment and one year out of retention to evaluate the root length, root canal wall thickness, width of the apical foramen, and degree of root bending, alveolar bone height and thickness. The crown-to-root ratio was calculated. The periodontal and endodontic conditions were evaluated. The parameters of the treated incisors and contralateral ones served as controls were compared. Results Nine impacted teeth were treated successfully. Throughout the treatment, the root of impacted central incisor continued to develop and the alveolar bones also continued to develop and remodel. The condition of the alveolar bone of vertically impacted teeth was better than that of horizontally impacted ones. No periodontal pocket or pulp necrosis was found after treatment. Seven patients were examined one year after treatment. No significant differencewas found in root length, palatal alveolar bone level and palatal alveolar bone thickness. The control group root length was （13.07±2.15） mm, the treatment group root length was （12.06±2.00） mm. No further alveolar bone loss, gingival recession and pulp necrosis were found. The control group labial and palatal alveolar bone levels were （0.90 ± 0.62）, （0.45 ± 0.52） ram, labial and palatal alveolar bone thickness were （0.85 ± 0.14）, （1.21±0.41） mm. The treatment group labial and palatal alveolar bone levels were （2.18 ± 1.59） ram, （0.57 ± 0.71） mm, labial and palatal alveolar bone thickness were （0.48 ± 0.29）, （1.43 ± 0.31） mm. Conclusions Orthodontic therapy for impacted maxillary central incisor in the mixed dentition could promote root development and alveolar bone remodeling. Good periodontal and endodontic conditions were achieved.