螺旋CT在口腔正畸微种植支抗植入术诊断中的应用

目的：应用螺旋CT及其三维重建技术对口腔正畸微种植支抗植入术结果判断，探讨其辅助临床获得明确诊疗结论的应用价值．方法选择20例正畸患者，共植入48颗微种植螺钉．使用 SOMATOM Sensation40/64螺旋CT．将螺旋CT轴位平扫数据使用西门子3D后处理软件进行多平面重建（MPR）、最大密度投影（MIP）、容积再现（VR）和曲面多层面重建（CPR）．将轴位扫描图像与不同方法重建图像之间相互对照、观察和分析．结果37颗微螺钉种植效果满意，无伤及邻近牙根及周围重要组织结构的情况；11颗微螺钉植入不理想，或作观察或作再植入而获成功．螺旋CT横轴位首先观察牙根间距及牙根与微种植螺钉关系效果好；VR观察微种植螺钉与牙齿、颌骨的外表轮廓整体关系表现直观；MIP观察微种植螺钉全貌与牙齿的关系效果理想，可任意旋转，从不同角度进行观察；MPR观察微种植螺钉与牙根局部细微结构及周围组织结构关系从可选择截面上显示清晰，弥补横轴位局限的缺点，同时便于测量长轴间距及倾斜角度．结论螺旋CT及其三维重建可准确地展现颌骨内微种植螺钉的形态、位置及其与邻牙的空间关系，影像显示清晰、直观、明确，作为有力的辅助检查手段在口腔正畸微种植支抗诊疗中有着很高的应用价值.

Application of Spiral CT in Orthodontic Micro-implant Anchorage Implantation Diagnosis

Objective To evaluate the results of orthodontic micro- implant anchorage implantation by application of Spiral CT and three-dimensional reconstruction techniques,so as to explore its application value in assisting clinical diagnosis and treatment. Methods 20 orthodontic patients were implanted with 48 micro-planting screws. SOMATOM Sensation40/64 helical CT scan was performed . The axial unenhanced helical CT data were given multi-planar reconstruction （MPR）,maximum intensity projection （MIP）,volume rendering （VR） and surface multidimensional reconstruction （CPR） by using the Siemens 3D post-processing software. The axial scanning images and reconstructed images were compared, observed and analyzed . Results The planting results of 37 micro screws were satisfactory without injuring the vital tissues surrounding the root. The planting results of 11 micro-screw were not ideal, and these micro-screws were observed or reimplanted and got success. Spiral CT axial scan showed better the tooth root interval and the relationship between tooth root and the planting screws. VR can directly showed the overall relationship between the planting screws and teeth , jaw contour appearance. The relationship between the screw and tooth was showed satisfactorily by MIP which could rotate freely and observe from different angles. MPR could clearly show the structural relationships between micro-root planting screws and tooth root and surrounding tissues from the cross section, and could make up for the shortcomings of axial limitations, and was easy to measure the distance and tilt angle of the long axis . Conclusion Spiral CT and three-dimensional reconstruction＆amp;nbsp;can accurately show the jaw micro planting screw shape,location and spatial relationships with adjacent teeth , the image is clear,intuitive and definite,and spiral CT and three-dimensional reconstruction has high application value in orthodontics micro-implant anchorage clinic as a powerful auxiliary examination means.