不同矢状骨面型成人下颌磨牙远中舌侧间隙的CBCT研究

A CBCT study on distolingual space of mandibular molars in adults with different sagittal skeletal patterns

目的研究不同矢状骨面型成年患者下颌磨牙远中舌侧间隙大小,分析限制下颌磨牙远中移动的主要骨性解剖位置,为临床磨牙远移方案的制定提供指导。方法选取97例于南京医科大学附属口腔医院正畸科就诊并符合纳入标准的成年患者,根据ANB角将患者分为骨性Ⅰ类组(n=28)、骨性Ⅱ类组(n=49)、骨性Ⅲ类组(n=20),将患者CBCT数据导入Dolphin软件进行重建,测量根分叉水平及距根分叉向根方2、4、6 mm平面第二磨牙远中根宽度、牙槽骨宽度,远中根远中和舌侧最凸点距下颌骨舌侧骨皮质内缘的距离。使用SPSS 26.0软件进行统计学分析,应用单因素方差分析和LSD⁃t检验比较不同矢状骨面型患者各测量项目间的差异。结果各测量平面,牙根宽度均显著小于牙槽骨宽度,差异有统计学意义(P<0.01)。不同矢状骨面型患者下颌磨牙远中舌侧间隙均小于远中间隙,且间隙大小随着测量层面加深逐渐减小,在R4和R6测量平面达到最小值。本研究的测量结果显示:R6水平处,骨性Ⅱ类组磨牙远中舌侧间隙最小,平均为(2.30±2.45)mm;骨性Ⅲ类患者磨牙远中舌侧间隙最大,平均为(4.17±2.38)mm。结论临床设计下颌磨牙远移方案时应参考CBCT,更多关注下颌磨牙远中舌侧牙槽骨量,对于轻中度牙列拥挤的骨性Ⅰ类及Ⅲ类患者,磨牙远移是一种安全且有效的治疗方式。

Objective To study the distolingual space of mandibular molars in adult patients with different sagittal skeletal patterns,and to analyze the main bony anatomical sites that restrict molar distalization,in order to provide guidance for the treatment plan of molar distalization.Methods A total of 97 adult patients according to the inclusion criteria were selected from the Department of Orthodontics,the Affiliated Stomatological Hospital of Nanjing Medical University.The patients were divided into skeletal ClassⅠgroup(n=28),skeletal ClassⅡgroup(n=49)and skeletal ClassⅢgroup(n=20)according to the ANB angle.CBCT of the patients were imported into Dolphin software for 3D reconstruction.The width of the distal root of the second molar,the width of alveolar bone,the distance between the most convex point of the distal and lingual side of the distal root and the inneredge of the lingual cortex of the mandible were measured at the 2,4,and 6 mm plane from the root furcation to the root apex.Statistical analysis was performed using SPSS 26.0 software,and univariate analysis of variance and LSD⁃t test were used to compare the difference.Results Root width was significantly narrower than alveolar bone width at all measurement planes(P<0.01).Molar distolingual space in patients with different sagittal skeletal patterns was smaller than molar distal space,and the size of the space gradually decreased with the deepening of the measurement level,reaching the minimum value at the R4 and R6 measurement planes.Measurement results of this study showed that at the R6 level,the molar distolingual space in skeletal ClassⅡgroup was the minimum(2.30±2.45)mm;on the contrary,skeletal ClassⅢgroup was the maximum(4.17±2.38)mm.Conclusion When designing the plan of molar distalization in clinical practice,CBCT should be used,and more attention should be paid to the lingual alveolar bone mass of the mandibular molar.It is a safe and effective treatment method for skeletal ClassⅠandⅢpatients with mild to moderate dental crowding.