3-D打印技术在下颌前突畸形治疗中的应用

APPLICATION OF THREE-DIMENSIONAL PRINTING TECHNIQUE IN CORRECTION OF MANDIBULAR PROGNATHISM

目的 探讨术前应用3-D打印技术制备头颅三维模型预塑形钛板，辅助下颌骨升支矢状劈开术（sagittal splint ramous osteotomy，SSRO）治疗下颌前突畸形，防止髁状突移位等并发症的临床疗效。 方法2012年1月－2013年5月，收治12例下颌前突畸形患者。男9例，女3例；年龄19～35岁，平均25.6岁。均为Angle Ⅲ类错颌。术前经螺旋CT扫描并重建数据后，采用Z Corp快速成型打印机，以快速成型粉打印头颅三维模型。在下颌骨模型上施行SSRO，以颌板固定远心端骨段的位置，在骨块移动至理想位置后，塑形钛板连接远、近骨段。术中使用预塑形钛板指导骨块移动和固定。结果术前采用3-D打印技术顺利完成头颅三维模型制作及钛板预塑形；根据钛板形状顺利完成手术。术中共放置24块钛板，均达完全贴附。术后6周CT三维重建检查示，与术前比较髁状突无位置改变。患者均获随访，随访时间7～12个月，平均10.6个月。患者面部比例协调、左右对称，下颌前突畸形均明显改善，牙颌关系稳定，颞颌关节区无不适症状，张口、咀嚼功能良好。 结论SSRO 术前应用3-D打印技术制备头颅三维模型预塑形钛板，在术中能起到导板作用，指导骨块移动，提高了手术安全性和精确性，显著降低了颞颌关节功能紊乱等并发症的发生。

Objective To establish a method to prefabricate titanium plate with three-dimensional （3-D） printing technique for correction of mandibular prognathism in sagittal splint ramous osteotomy （SSRO）. Methods Between January 2012 and May 2013, 12 patients with mandibular prognathism （Angle III malocclusion） were treated. Among them, 9 cases were male and 3 cases were female. Their ages ranged from 19 to 35 years （mean, 25.6 years）. With the 3-D facial CT data of these patients, 3-D printer was used to print the models for preoperational simulation. SSRO was performed on 3-D models, and the titanium plates were prefabricated on the models after the distal segments were moved backward and rotated according to occlusal splint. During operations, the proximal segments were fixed to distal segments by the prefabricated titanium plates. 3-D CT scans were taken to examine the temporomandibular joint position changes before operation and at 6 months after operation. Results The skull models were manufactured by 3-D printing technique, and the titanium plates were reshaped on the basis of them. Twenty-four prefabricated titanium plates were placed during operations, and they all matched with the bone segments well. Evaluation of 3-D CT scans showed that the temporomandibular joint position had no change. All patients were followed up 7-12 months （mean, 10.6 months）. The face type and dental articulation were improved greatly. All cases obtained satisfactory opening function and occlusion. Conclusion With the titanium plate fabricated based on 3-D models, surgeons are able to improve or refine surgical planning so that the operation can be performed according to preoperative simulation precisely and the complications, such as dislocation of temporomandibular joint, can be prevented.