螺旋CT三维重建颌骨内埋伏牙位置形态及与周围组织的关系

背景：埋伏牙会造成恒牙的异位，咬牙合 紊乱并影响美观和咀嚼功能。而清晰的影像评价是正确诊断的重要组成部分。目的：应用螺旋CT三维重建技术对颌骨内埋伏牙进行术前定位评估。方法：23例埋伏牙患者使用传统平片和螺旋CT进行术前检查。螺旋CT横断面扫描后应用表面阴影遮盖技术和多平面重建技术对埋伏牙进行三维重建。分别通过传统平片和螺旋CT三维重建图像对埋伏牙进行术前评估。所有埋伏牙最终经外科拔除证实，分别计算平片和螺旋CT诊断的准确性。 结果与结论：螺旋CT三维重建能够清楚呈现埋伏牙的位置，形状及其与邻近组织结构的关系。传统平片和螺旋CT对埋伏牙位置评估的准确性分别是37.0%和100%，对牙根弯曲诊断的准确性为44.4%和88.9%。结果表明，螺旋CT三维重建技术能够清楚显示颌骨内埋伏牙的位置，形态及与周围组织结构的关系，从而有利于制定个性化，恰当的口腔治疗方案。

Spiral CT three-dimensional reconstruction of location and shape of impacted teeth and correlation with peripheral tissues

BACKGROUND:Impacted teeth lead to permanent teeth aberrance, occlusal disharmony and affects beauty or masticatory functions. A clear imaging evaluation plays an important part of correct diagnosis.  OBJECTIVE:Application of three-dimensional (3D) reconstruction technology of spiral CT to impacted teeth in bone for preoperative evaluation. METHODS:A total of 23 patients were examined with plain radiograph and spiral CT before performing an operation for extraction. After CT scanning, shaded surface display (SSD) and multiplanar reformation (MPR) was used to get 3D CT images of the impacted teeth. The plain radiographs and the 3D CT images were used for preoperative evaluation respectively. All the teeth were finally extracted and evaluated during the operation. The diagnostic accuracy of the plain radiographs and the CT images for location and root malformation evaluation was calculated and compared. RESULTS AND CONCLUSION:The 3D CT images clearly presented the impacted teeth: the location, the shape and the relationship with the adjacent teeth. The accuracy of plain radiographs and the 3D CT images for location evaluation was 37.0% and 100% and was 44.4% and 88.8% for root malformation. The 3D reconstruction technology of spiral CT is useful to get more information about the impacted teeth to have individual, proper and effective treatment.