第二恒磨牙正锁[牙合]患者牙体及牙周组织的锥形束CT研究

A CBCT study of teeth and periodontal tissues with second molar scissors bite

目的:本研究利用CBCT测量了第二磨牙正锁[牙合]患者牙体及牙周组织的相关数据,对比对照组与单侧正锁[牙合]组及双侧正锁[牙合]组的差异。方法:选取锦州医科大学附属二院2015年1月—2020年6月收治的第二磨牙正锁[牙合]患者50例,设为正锁[牙合]组;另选取同期来我院进行口腔检查的双侧后牙覆[牙合]覆盖正常的志愿者50名,设为对照组。最终纳入测量的为单侧组只计算患侧为38例,双侧组两侧均计算为24例,对照组两侧均计算为100例。拍摄CBCT,测量第二磨牙的颊舌向倾斜度(牙冠转矩和牙长轴倾斜度)、牙槽骨厚度、牙槽骨倾斜度、阻抗中心间宽度,并对测量数据进行统计分析。结果:单侧组、双侧组与对照组的第二磨牙转矩交角和牙长轴倾斜度交角差异具有统计学意义(P<0.05);三组牙槽骨厚度方面差异均有统计学意义(P<0.05);对照组与锁[牙合]组牙槽骨倾斜度差异显著(P<0.05);对照组上颌第二磨牙的阻抗中心间宽度显著大于单侧组及双侧组,对照组下颌第二磨牙的阻抗中心间宽度显著小于单侧组及双侧组(P<0.05)。结论:第二磨牙正锁[牙合]会导致咀嚼运动方式及咬合肌力改变;第二磨牙正锁[牙合]患者牙槽骨厚度显著缩小,牙周风险会升高;个体生长发育过程中,牙体的倾斜会导致牙槽骨的倾斜。

Objective In this study,CBCT was used to measure the relevant data of teeth and periodontal tissues of the patients with second molar scissors bite,and to compare the differences between the control group,the unilateral scissors bite group and the bilateral scissors bite group.Methods Fifty patients with second molar malocclusion treated in the Second Affiliated Hospital of Jinzhou Medical University from January 2015 to June 2020 were selected as the malocclusion group;In addition,50 volunteers with normal occlusal coverage of bilateral posterior teeth who came to our hospital for oral examination in the same period were selected as the control group.Finally,38 cases were included in the unilateral group,24 cases in both sides of the bilateral group and 100 cases in both sides of the control group.CBCT was performed to measure the buccal lingual inclination(crown torque and tooth axis inclination),alveolar bone thickness,alveolar bone inclination and resistance center width of the second molar,and the measured data were statistically analyzed.Results There were significant differences in torque angle and inclination angle of long axis between unilateral group,bilateral group and control group(P<0.05);There were significant differences in alveolar bone thickness among the three groups(P<0.05);There was significant difference in alveolar bone inclination between control group and lock bite group(P<0.05);The width between impedance centers of maxillary second molars in the control group was significantly larger than that in the unilateral and bilateral groups,and the width between impedance centers of mandibular second molars in the control group was significantly smaller than that in the unilateral and bilateral groups(P<0.05).Conclusion Scissors bite of the second molar leads to changes in the masticatory movement pattern and occlusal muscle strength.In the second molar scissors bite,the mandibular lingual dislocation was larger,which resulted in a significant reduction in the thickness of alveolar bone.In the process of individual growth and development,the inclination of tooth will lead to the inclination of alveolar bone.