Zhou Zi-Qian, Chen Zhen-Qi
Department of Orthodontics, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine; College of Stomatology, Shanghai Jiao Tong University; National Center for Stomatology; National Clinical Research Center for Oral Diseases; Shanghai Key Laboratory of Stomatology; Shanghai Research Institute of Stomatology. Shanghai 200011, China. E-mail:
Shanghai Kou Qiang Yi Xue. 2022 Dec;31(6):661-667.
To investigate the impact of maxillary sinus floor on the mesial movement of maxillary first molar.
Orthodontic patients with maxillary first premolars extracted were selected. Their maxillary first molars were divided into case group and control group according to whether their roots were in contact with the maxillary sinus floor. The case group was further divided into three subtypes according to the depth of the root extruded into the maxillary sinus. A total of 64 maxillary first molars from 32 patients were enrolled in this study, including 34 in the case group (five in subtype Ⅱ, fourteen in subtype Ⅲ, and 15 in subtype Ⅳ) and 30 in the control group. The mesial movement distance of each root and crown and the inclination of each root long axis were measured, and resorption of each root was evaluated. SPSS 22.0 software package was used for data analysis.
After orthodontic treatment, the mesial movement distance of roots from both groups were all lager than 2 mm. The mesial movement distance of the crown was not statistically different between the two groups (P＞0.05), while the mesial movement distance of the roots in the control group was significantly larger than in the case group（P＜0.05）. Inclined movement towards the mesial direction was found in both groups, and the inclination angle was significantly larger in the case group（P＜0.05）. The inclination angle of the first molars in the subtype Ⅳ was significantly larger than that in the subtype Ⅲ and the control group. Most of the maxillary first molars from both groups had no obvious root resorption（P＞0.05）.
With the proper force system, maxillary first molars with roots extruded into the maxillary sinus floor can be moved mesialy with mild or no root resorption, while a larger inclination can be found compared with maxillary first molars without root extruding into the maxillary sinus floor. The deeper the root extruding into the maxillary sinus, the larger the inclination angle will be.
探讨上颌窦底对上颌第一磨牙近中移动的影响。
选取拔除上颌第一前磨牙的正畸患者。根据上颌第一磨牙牙根是否与上颌窦底接触，将其分为病例组和对照组。病例组再根据牙根突入上颌窦的深度分为三个亚型。本研究共纳入32例患者的64颗上颌第一磨牙，其中病例组34颗（Ⅱ型5颗、Ⅲ型14颗、Ⅳ型15颗），对照组30颗。测量各牙根和牙冠的近中移动距离以及各牙根长轴的倾斜度，并评估各牙根的吸收情况。采用SPSS 22.0软件包进行数据分析。
正畸治疗后，两组牙根的近中移动距离均大于2 mm。两组牙冠的近中移动距离差异无统计学意义（P＞0.05），而对照组牙根的近中移动距离显著大于病例组（P＜0.05）。两组均出现向近中方向的倾斜移动，且病例组的倾斜角度显著更大（P＜0.05）。Ⅳ型第一磨牙的倾斜角度显著大于Ⅲ型和对照组。两组上颌第一磨牙多数无明显牙根吸收（P＞0.05）。
在合适的力系作用下，牙根突入上颌窦底的上颌第一磨牙可近中移动，牙根吸收轻微或无吸收，但其与牙根未突入上颌窦底的上颌第一磨牙相比，倾斜度更大。牙根突入上颌窦越深，倾斜角度越大。
