下颌低位阻生第三磨牙竖直前的螺旋CT三维重建定位研究

Clinical Application of Three Dimensional Reconstruction Technique of Spiral CT in Locating the Impacted Mandibular Third Molar with Uprighting Appliance

目的探讨下颌低位阻生第三磨牙竖直前螺旋CT三维重建定位的临床效果。方法对10例下颌低位阻生第三磨牙需竖直排齐的患者作螺旋CT扫描,采用容积重建,表面遮盖显示、多平面重建、最大密度投影,获得牙体表面立体图像及任意平面、曲面的断层影像,采用电子关节分离技术结合仿真内镜和染色技术,从不同角度旋转下颌骨进行观察。结果螺旋CT三维重建清晰显示了下颌低位阻生第三磨牙的立体形态,以及在下颌骨内三维方向的位置及与邻牙的立体接触关系。结论螺旋CT三维重建可作为下颌低位阻生第三磨牙竖直前准确有效的检查定位手段,对手术切口的设计、进路的选择、正畸牵引附件的安放及牵引方向的制定有显著指导作用。

Objective To discuss the clinical application of three-dimensional reconstruction technique of Spiral CT in locating the impacted mandibular third molar with uprighting appliance. Methods Ten cases with impacted mandibular third molar were examined with Spiral CT. All cases received volume reconstruction technique （VRT） , surface shaded display （SSD）, maximum intensity projection （MIP） and multiplanar reconstruction （MPR） method. Results The reconstruction image could clearly demonstrate the three dimensional shape of the impacted mandibular third molar in the mandible and the relation with the adjacent molar teeth. Conclusion The three-dimensional reconstruction of Spiral CT is an accurate and effective method to examine and locate the impacted mandibular third molar with uprighting appliance. It provides a guide to the incision design, the surgical route choosing, the placement of the orthodontic accessories as well as the direction of the orthodontic traction.