目的 应用锥形束CT(cone beam computed tomography, CBCT)对不同性 别及年龄组人群下颌骨颏部骨皮质厚度 进行测量分析。方法 通过Mimics软件在 颏部正中中线外3.0mm、颏孔前5.0mm之 间区域，取切牙或尖牙根尖下5.0mm、 7.0mm、9.0mm处三个层面，测量三个横 断面上颊侧和舌侧皮质骨厚度。对180名 患者(90名男性和90名女性)，年龄范围 从20岁到70岁，分成6组，测得数据进 行统计学分析。结果 20-30岁年龄组和 35-45岁年龄组男性和女性颊侧骨皮质较 60-70岁年龄组男性和女性厚，有统计学 意义(P＜0.05)。20-30岁年龄组男性和 女性颊侧骨皮质与35-45岁年龄组男性 和女性颊侧骨皮质厚度差异无统计学差 异(P＞0.05)。结论 前牙区舌侧骨皮质 厚度与年龄变化及与根尖距离无关，前 牙区颊侧骨皮质厚度与年龄变化呈负相 关、但与根尖距离无关。男性和女性在 根尖下9mm颊侧平均皮质骨厚度随年龄变 化呈负相关的可信度大。

Objective The aim of the study was to evaluate the change of the chin cortex thickness in different ages by cone-bean CT. Methods 180 patients (90 females and 90 males) which aged from 20 to 70 years old were divided into 6 groups. The ROI was chosen in 3 mm outside mandibular symphyseal and 5 mm in front of mental foramen. Three planes (5mm, 7mm, 9mm under root apical) were measured both buccal and lingual side by Mimics software. Results Buccal cortex thickness in group 20-30 years-old and group 35-45 years-old were thicker than group 60-70 years-old for both femals and male(P＜0.05). There was no significant statistical difference in goup 20-30 years-old and 35-45 years-old for the buccal side and in every group for lingual side. Conclusion The buccal chin cortex is negatively correlated with age, and has nothing to do with the distance under root apical. The phenomenon is more apparent in 9mm under root apical.