目的：采用临床直接测量、平行投照根尖片和锥形束CT（cone-beam computed tomography，CBCT）评价存在骨缺损的磨牙拔牙同期位点保存6个月后牙槽骨的变化，并分析不同方法的测量效果。方法：纳入20名患者共23颗因牙周病变拔除的磨牙，牙齿拔除后应用去骨蛋白牛骨基质（deproteinized boving bone mineral，DBBM，Bio-Oss）和可吸收膜（bioabsorbable collagen membrane, Bio-Gide）进行拔牙位点保存术，术中临床直接测量，术后即刻及术后6个月拍摄平行投照根尖片和CBCT，通过上述3种方法测量分析术后6个月牙槽骨高度和宽度的变化并比较测量效果的异同。结果：比较23个拔牙位点的牙槽骨高度在拔牙位点中央、远中中央、颊侧远中3个观察点的术中临床测量与CBCT测量的结果，差异无统计学意义（P>0.05），其他观察点的高度及宽度测量结果差异有统计学意义(P<0.05)。术后6个月接受翻瓣再进入实施种植的10名患者中，拔牙位点中央相应观察点的牙槽骨高度显著增加，临床直接测量和CBCT测量分别增加（6.15±1.73） mm和（6.59±2.53） mm，牙槽骨宽度测量值分别为（8.45±1.18） mm和（8.52±1.27） mm，两种方法测量结果差异无统计学意义（P>0.05）；应用平行投照根尖片观察术前和术后6个月拔牙位点中央的牙槽骨高度变化为增加（5.84±4.28） mm，测量数值与另两种方法接近。结论：存在骨缺损的磨牙应用BioOss与BioGide进行拔牙位点保存后，临床直接测量和CBCT测量两种方法对牙槽嵴顶骨高度和宽度变化的评价基本一致。

Objective：To investigate the changes of the vertical height and width of the alveolar bone six months after the alveolar ridge preservation in periodontal compromised molar sites of severe alveolar bone defects with clinical direct measurement, parallel periapical radiographs, and cone-beam computed tomography (CBCT), and to analyze the effect of the three different methods of measurement. Methods: In this study, 20 subjects requiring tooth extraction on account of periodontal disease with a total of 23 extracted molars were enrolled. Extractions were performed atraumatically and patients were received alveolar ridge preservation procedure with Bio-Oss-and Bio-Gide-Clinical direct measurements were taken after tooth extraction and during the implant surgery 6 months later, CBCT scans and parallel periapical radiographs were taken immediately after ridge preservation and 6 months later. The changes of alveolar ridge width and vertical height after six months were measured and analyzed through the above-mentioned three methods and the similarities and differences of the measured effect were compared. Results: There were no significant difference of alveolar vertical height in the center of the extraction sites, the center of distal aspect, and distobuccal aspect between the clinical direct measurements and the CBCT measurements (P>0.05), alveolar vertical height in other points and alveolar width measurements were statically significant (P<0.05). After 6 months, 10 sites of 10 subjects were received a flap and reentered to perform dental implants surgery. The vertical height in the center of alveolar increased significantly and the changes of alveolar vertical height of clinical direct and CBCT measurement were （6.15±1.73） mm and （6.59±2.53） mm, respectively. The measurements of the width of the alveolar bone were （8.45±1.18） mm and （8.52±1.27） mm, respectively. The measurements of the two methods were not statistically significant (P>0.05). The change of the alveolar height in the center of the extraction socket after six months measured by parallel periapical was （5.84±4.28） mm, which was closed to the clinical direct measurement and the CBCT measurement. Conclusion: Clinical direct measurement and CBCT measurement were largely consistent in the evaluation of the alveolar bone height and width after the alveolar ridge preservation using deproteinized boving bone mineral (DBBM, Bio-Oss^R) and bioabsorbable collagen membrane (Bio-Gide^R) in periodontal compromised molar sites of severe bone defects.