缺牙区松质骨密度的定量CT法测量

Bone mineral density of cancellous bone in edentulous areas: quantitative CT measurement

背景:运用定量CT的原理可以准确地测得单位体积内骨密度。牙齿缺失后,牙槽骨愈合过程中存在一定程度的骨吸收,种植前准确评估拟种植区松质骨密度尤为重要。目的:测量牙齿缺失后缺牙区松质骨密度的变化及探讨不同性别、年龄、颌骨区域松质骨密度有无差异。方法:运用定量CT的原理校正锥形束CT扫描所得的锥形束CT值。对90例患者进行锥形束CT扫描后,得到患者缺牙区与对照区(同颌对侧同名牙区)各自骨密度(mg/cm3)。结果与结论:(1)患者缺牙后缺牙区松质骨骨密度降低(P<0.001);(2)缺牙区松质骨密度、对照区正常松质骨密度以及缺牙后松质骨密度的减少量与性别无关;(3)缺牙区松质骨密度及缺牙后松质骨密度的减少量与年龄无关,而对照区正常松质骨密度随年龄增大而减小(P<0.05);(4)上下颌骨不同区域松质骨密度下颌后牙区>下颌前牙区>上颌前牙区>上颌后牙区(P<0.05);(5)结果证实,实验采用定量CT法成功测量缺牙区松质骨密度变化。

The bone mineral density(BMD)in unit volume can be accurately measured with the theory of quantitative CT.After tooth loss,bone resorption certainly exists in the alveolar bone healing.Therefore,it is important to accurately evaluate the BMD of cancellous bone in the plantation area before implantation.OBJECTIVE:To evaluate the changes in BMD of alveolar cancellous bone after the loss of tooth,and explore whether the BMD shows the differences in different genders,ages and dental sites.METHODS:Corrected voxel values were obtained from the cone-beam CT with the theory of quantitative CT.Ninetypatients underwent cone-beam CT,and their BMD(mg/cm3)in dentulous areas and control areas(homonymous region of the same jaw)was obtained.RESULTS AND CONCLUSION:The BMD of alveolar cancellous bone reduced after the loss of tooth(P<0.001).The BMD reduction of the edentulous cancellous bone,normal cancellous bone and the cancellous bone after tooth loss had no correlation with gender.The BMD reduction of the edentulous cancellous bone and the cance llous bone after tooth loss was not associated with age(P>0.05),while the BMD of the control area decreased with increasing age(P<0.05).The order of the BMD of cancellous bone was as follows:mandibular posterior region>mandibular anterior region>maxillary anterior region>maxillary posterior region.To conclude,quantitative CT is a available method for detecting the changes in the BMD of alveolar cancellous bone after tooth loss.