计算机辅助设计与快速成形技术制作上颌骨缺损模型的临床应用初探

目的探寻利用计算机辅助设计（computer aided design，CAD）与快速成形技术制取上颌骨缺损模型的新方法，以弥补传统模型制取方法的不足。方法将12例上颌骨缺损患者的头部CT数据输入计算机，经Mimics 8．11软件和Geomagic 7．0软件处理后，得到缺损部位的三维影像数据，利用快速成形技术，获得缺损部位的树脂模型。根据树脂模型制作阻塞器，利用缺损部位的组织倒凹固位使阻塞器独立固定在缺损腔中。再行可摘义齿修复，将阻塞器和可摘义齿用磁性附着体连接。检查临床修复效果并用鼻音计测量5例患者阻塞器戴人前后的鼻音化率值。结果阻塞器和可摘义齿可分段戴人患者口内，两者固位、稳定等临床效果均较好。鼻音计测量结果显示，阻塞器戴人后患者的非鼻辅音语音样本的鼻音化率值降低，由戴人前的（46．53±13．86）％降为戴人后的（22．60±8．52）％，差异有统计学意义（P〈0．001）。结论利用CAD与快速成形技术制取上颌骨缺损部位模型是一种可行的方法。

Application of computer aided design and rapid prototyping technology for defected maxilla restoration

OBJECTIVE: To test a new cast-making method based on computer aided design (CAD) and rapid prototyping (RP) technology for defected maxilla. METHODS: Head CT data of 12 patients with defected maxilla were transmitted into a computer. Three-dimensional digital image of the patient's defected maxilla was then obtained based on Mimics 8.11 and Geomagic 7.0 and the plastic cast of the defected region was manufactured by prototyping. The obturator was made on this plastic cast that duplicated the undercut tissue of defected area. The prominent part of the obturator was made of elastic heat-curing resin and it was helpful to gain the retention through the engagement between the obturator and the tissue undercut. After the obturator was finished, the upper removable partial denture was fabricated in conventional method. The combination of these two parts was achieved using magnetic attachment. Clinical effects of obturator and removable partial denture were evaluated and the nasalance value of 5 patients before and after insertion of the obturator was measured using nasometer. RESULTS: The obturator and removable partial denture could be seated into place separately. They all had good retention and stability. After the obturator was seated in place, the nasalance of nonnasal and vowel text decreased from (46.53 +/- 13.86)% to (22.60 +/- 8.52)% (P < 0.001). CONCLUSIONS: The cast-making method based on CAD and RP technology for cast-making of defected maxilla is feasible and practical.