一种新的CT技术及其在骨内埋伏牙定位中的应用

<title>New CT Technique and its application to investigate location of impacted teeth in bone

目的 探索螺旋CT三维重建技术对埋伏牙的应用价值。方法 25例病人采用GE Hispeed螺旋CT扫描机,自下颌骨下缘向颅顶行横轴位螺旋扫描。采用表面遮盖法(SSD),骨最大密度投影法(MIP)成像,多层面重建术(MPR)成像。结果能清晰显示骨内埋伏牙的形态,唇侧或腭侧位置,萌出方向及与邻牙关系。结论 螺旋CT三维重建技术是一种既能立体展示牙齿表面形态,又能精确判断牙齿位置和距离测量的影像学技术。

<abstract>jective To study the useful value of three dimensional reconstruction technique in impacted teeth in bone. Methods We used GE HiSpeed CT/I helical CT to scan from the bottom of mandible to the top of skull along the transverse axis in 25 cases. At 120KV,240mA, 1.0S,after scanning with 3mm thickness,20 to 25 layers,21cm scan range and 512×512 array we obtained 3D reconstruction image by means of MIP( maximum intensity projection) ,SSD( surface shaded display) and MRR( multi - planar reconstructions) with the scan datum. Result The reconstructaction image can clearly present the dental surface image including crown, root, neck and root bifurcation in three dimensional way, labial or palatal location eruption,orientation and relation with dentition in anterior maxilla. Conclusion 3D reconstruction technique with helical CT is a technique to display three dimensional surface configuration of teeth and to measure its location precisely. This technique can be applied to examine impacted teeth in bone before surgical and orthodontic treatment.