下颌第一磨牙缺失间隙关闭前后的骨量变化

Changes of bone mass in space missing mandibular first molar before and after closure

目的 研究下颌第一磨牙缺失区骨量与正畸关闭间隙后移入间隙的第二磨牙骨丧失量之间的关系,为风险预判及预后提供参考。方法 选取下颌第一磨牙缺失的正畸患者50例,行全口固定矫治,微种植体支抗辅助近中移动磨牙关闭间隙。治疗前后分别拍摄锥形束CT,并测量骨量。运用SPSS22.0统计软件分析数据。结果 测量的下颌第二磨牙8个位点中7个位点的平均骨高度丧失量均小于1 mm。骨高度增加的位点占34.5%,90%的磨牙存在骨高度增加的位点。下颌第一磨牙缺失区牙槽骨的高度吸收量、宽度吸收量与移入缺牙嵴的第二磨牙骨高度丧失量均不存在显著相关性。结论 通过正畸近中移动相邻磨牙关闭下颌第一磨牙缺失间隙不会造成严重的磨牙骨高度丧失,还可能形成骨高度的增加。缺牙区的骨吸收量不提示治疗风险,该项治疗前也无需行植骨术。

Objective To study the relationship between bone mass of space missing mandibular first molar and bone loss of the mandibular second molars moved into the space, and to provide reference for risk prediction and prognosis in clinical treatment. Methods Fifty orthodontic patients with mandibular first molar loss were included in the study. Patients were treated with bracket, and the space was closed by mesially moving molars with the aid of implant anchorage. Cone-beam CT was taken and bone mass was measured before and after treatment. SPSS22.0 statistical software was used to analyze the data. Results The mean bone height loss of mandibular second molars at seven out of eight sites was less than 1 mm. Moreover, 34.5% of all sites had bone height increase, and 90% molars had sites with bone height increase. The height and width absorption of alveolar bone in space missing mandibular first molar had no significant correlation with the bone height loss of the mandibular second molar moved into space. Conclusion Closing the space missing mandibular first molar by orthodontic mesial movement of adjacent molars will not cause severe bone loss, and even the increase of bone height may be obtained at some sites. Risk of treatment cannot be predicted through the absorption of alveolar bone in the tooth missing area, and incremental bone surgery is unnecessary before treatment.