下颌第一磨牙区舌侧凹陷的锥形束计算机断层扫描研究

Study on Lingual Concavities of Mandibular First Molar with Cone Beam Computed Tomography

目的:通过锥形束计算机断层扫描(CBCT)对下颌第一磨牙缺牙区舌侧凹陷的发生率和程度进行研究,以减少种植手术过程中发生舌侧骨穿孔的风险。方法:根据纳入排除标准收集107例成人患者的CBCT资料,选取下颌第一磨牙缺牙区截面影像,根据下颌第一磨牙区牙槽嵴的形状将下颌第一磨牙区颌骨形态分为凸型(C型)、直型(P型)、凹型(U型);确定每组的发生率,通过选定的解剖标志测量舌侧凹陷的角度、深度,并分析其特征。结果:在107例患者中,下颌第一磨牙区舌侧凹陷(U型)发生率为29.0%,凹陷的平均角度为(57.77±8.68)°;凹陷的平均深度(LCD)为(2.77±0.80)mm;舌侧最凸点(P)到牙槽嵴顶(Vc)和下颌下缘(Vd)的平均垂直距离分别为(11.61±1.73)mm和(15.33±2.65)mm。结论:下颌磨牙区舌侧倒凹的存在为在该区域进行种植手术增加了潜在风险,本研究中下颌第一磨牙缺牙区舌侧倒凹的发生率为29.0%;CBCT影像可以准确描述下颌磨牙区域的解剖特征,为制定种植计划提供重要的参考信息。

Objective:To study the prevalence and the degree of lingual concavity in the mandibular first molar edentulous region from cone-beam computed tomography(CBCT)scans to reduce the risk of perforating the lingual cortical bone during the process of dental implantation.Methods:The CBCT data of 107 adult patients were collected according to the inclusion and exclusion criteria.Cross-sectional images of mandibular first molar area were selected.The jawbone morphology of mandibular first molar regions was classified as U-configuration(undercut),P-configuration(parallel),or C-configuration(convex).The prevalence of each group was determined.The lingual concavity characters,including the depth and the angulation,were determined by the measurements of selected anatomic landmarks.Results:Among 107 patients,the lingual undercuts(U-configuration)had a prevalence of 29.0%in the mandibular first molar region.The mean concavity angle was(57.77±8.68)°and the mean linear concavity depth(LCD)was(2.77±0.80)mm.The mean vertical distances of point P from the alveolar crest(Vc)and from the inferior mandibular border were(11.61±1.73)mm and(15.33±2.65)mm,respectively.Conclusion:The existence of lingual concavity in mandibular molar area increases the potential risk of implant surgery.CBCT image can accurately describe the anatomical characteristics of mandibular molar area and provide important reference information for making implant plan.