基于CBCT分析下颌第三磨牙空间位置对邻牙的影响

Analysis of the Influence of Spatial Position of Mandibular Third Molars on Adjacent Teeth Based on CBCT

摘要: 目的：使用CBCT分析探讨下颌第三磨牙(Mandibular Third Molars, M3Ms)的空间位置对下颌第二磨牙(Mandibular Second Molars, M2Ms)牙根吸收及牙槽骨吸收的影响。方法：收集2023年5月至2024年5月在安徽医科大学附属巢湖医院就诊并拍摄CBCT的患者。选择双侧均有M3Ms的患者400例，共800颗牙齿。利用软件MYDCS重建CBCT图像并测量。对测量结果进行分析，评估M3Ms的阻生类型、牙骨质–牙釉质界距离、两牙的接触部位、M3Ms的水平空间位置对于M2Ms远中牙根吸收的患病率6 mm~9 mm、接触部位位于颈部、水平空间位置为颊位；M2Ms远中牙槽骨丧失程度的危险因素为低位埋伏、III类关系、水平倾斜、牙骨质–牙釉质界距离 > 9 mm、接触部位位于根部、水平空间位置为颊位。结论：当M3Ms的水平空间位置位于颊位是M2Ms牙根吸收和牙槽骨吸收的一个新的危险因素；M2Ms远中牙槽骨丧失程度能够更精确的反映M2Ms远中牙槽骨因M3Ms而导致的吸收情况；临床医师应充分的评估M3Ms的空间位置对于M2Ms的不良影响，为患者提供正确的早期干预手段。

Abstract: Objective: To investigate the effect of spatial position of mandibular third molars (M3Ms) on root resorption and alveolar bone resorption of mandibular second molars (M2Ms) based on CBCT. Method: Collecting patients who visited and had CBCT taken at Anhui Medical University Affiliated Chaohu Hospital from May 2023 to May 2024. Selecting 400 patients with M3Ms on both sides, totaling 800 teeth. Using software MYDCS to reconstruct CBCT images and measure them. Analyzing the measurement results and evaluating the impact of the impacted type of M3Ms, the distance between the cementoenamel junction, the contact site between the two teeth, and the horizontal spatial position of M3Ms on the incidence of distant root resorption and the degree of distant alveolar bone loss in M2Ms. Results: The risk factors for distant root resorption in M2Ms include horizontal inclination, a distance of 6 mm~9 mm between the tooth cementoenamel junction, contact location in the neck, and a horizontal spatial position in the buccal position; The risk factors for the degree of alveolar bone loss in M2Ms are low impaction depths, Class III relationship, horizontal inclination, distance between the tooth bone enamel junction > 9 mm, contact site located at the root, and horizontal position in the buccal position. Conclusion: When the horizontal spatial position of M3Ms is located in the buccal position, it is a new risk factor for root resorption and alveolar bone resorption in M2Ms; The degree of distant root resorption can more accurately reflect the absorption of M2Ms in the distal alveolar bone caused by M3Ms; Clinicians should fully evaluate the adverse effects of the spatial position of M3Ms on M2Ms and provide patients with the correct early intervention methods.