牙种植区骨密度的CBCT评价

Assessments of Jaw Bone Density at Implant Sites Using CBCT

目的：应用锥形束CT（cone beam computer tomography，CBCT）及Simplant软件，对拟种植的颌骨区骨密度定量测量，参考Lekholm和Zarb分类法对其进行分类，得出一种客观定量的颌骨质量分类方法。方法：通过CBCT对109例拟种植患者的上下颌骨扫描重建，应用Simplant软件对195个种植区骨密度进行测量，骨密度以Hounsfield units （HU）表示。采用SPSS19.0软件以Mann-Whitney U检验进行统计学分析，比较不同区域的骨密度差异。结果：所有拟种植位点平均骨密度为（369.15±181.60）HU。骨密度比较：下颌前牙区[（699.41±138.76）HU]＞上颌前牙区[（463.96±145.93）HU]＞下颌后牙区[（400.66±123.32）HU]＞上颌后牙区[（236.19±150.85）HU]。各类骨的密度参考值：Ⅳ类骨（D4）为＜200HU，Ⅱ/Ⅲ类骨（D2/3）为200～600HU，Ⅰ类骨（D1）为＞600HU。结论：下颌前牙区平均骨密度值最大，上颌后牙区平均骨密度值最小。据此得出一种客观的定量骨分类方法，对种植术前评估有重要意义。

Objective：To assess the bone density of dental implant sites using CBCT and Simplant software, and establish a quantitative ranges for each bone quality classification according to Lekholm and Zarb grouping. Methods： 109 patients’ jaw bone were scanned by CBCT, the images were reconstructed by the Simplant software. The bone density of 195 potential implant sites was measured and the results were recorded using Hounsfield units （HU）. The data was analyzed with SPSS 19.0 software package for Mann-Whitney U test. Results：The mean bone density in all implant sites was （369.15±181.60） HU. The rank of mean bone density was anterior mandible [（699.41±138.76） HU]〉anterior maxilla [（463.96 ±145.93） HU]〉posterior mandible [（400.66 ±123.32） HU]〉posterior maxilla [（236.19 ±150.85） HU]. Quantitative parameters ranged as follows： bone quality of D4 was less than 200 HU, bone quality of D2/3 was 200 to 600 HU, and bone quality of D1 was above 600 HU. Conclusion： Anterior region of mandible has the highest mean bone density and posterior region of maxilla has the lowest mean bone density. It is therefore proposed that an objective classification which confirms the importance of a site-specific bone tissue evaluation prior to implant installation.