Private Practice, Seoul.
Private Practice, Wonju.
Eur J Orthod. 2019 Sep 21;41(5):513-518. doi: 10.1093/ejo/cjz001.
To investigate the factors associated with the change in alveolar bone level of mandibular second and third molars after second molar protraction into the space of the missing first molar (L6) or second premolar (LE).
Fifty-one patients in whom space of the missing L6 or LE was treated with second molar protraction (13 males, 38 females, mean age 19.6 ± 4.7 years) from 2003 to 2015 were included. The alveolar bone level and position and angulation of the mandibular second and third molars were measured in panoramic radiographs at pre-treatment (T1), and after the alignment of the third molars following second molar protraction (T2). Factors associated with alveolar bone loss on the distal aspect of the mandibular second molars were assessed using linear regression analysis.
Age at T1 (P < 0.001) and third molar angulation at T1 (P = 0.002) were significant factors for the prediction of alveolar bone level distal to the second molars.
This study used two-dimensional panoramic radiographs, and we could observe only the interproximal bone level.
After second molar protraction into the missing first molar or second premolar space, mandibular second molars may exhibit alveolar bone resorption in the distal root in older patients and in those with mesially tilted third molars before treatment.
探讨第二磨牙远中移动至第一磨牙（L6）或第二前磨牙（LE）缺牙间隙后，下颌第二、第三磨牙牙槽骨高度变化的相关因素。
纳入 2003 年至 2015 年采用第二磨牙远中移动技术（13 名男性，38 名女性，平均年龄 19.6 ± 4.7 岁）治疗 L6 或 LE 缺牙间隙的 51 例患者。在治疗前（T1）和第二磨牙远中移动后第三磨牙排齐时（T2），全景片上测量下颌第二、第三磨牙牙槽骨高度、位置及倾斜角度。采用线性回归分析评估下颌第二磨牙远中牙槽骨丧失的相关因素。
T1 时的年龄（P < 0.001）和 T1 时第三磨牙倾斜角度（P = 0.002）是预测第二磨牙远中牙槽骨水平的显著因素。
本研究使用二维全景片，只能观察到近中骨高度。
第二磨牙远中移动至第一磨牙或第二前磨牙缺牙间隙后，年龄较大的患者和治疗前第三磨牙近中倾斜的患者下颌第二磨牙可能会出现远中根牙槽骨吸收。
