计算机辅助设计虚拟颌位在儿童颞下颌关节强直合并颌骨畸形同期矫治中的应用

目的:评价计算机辅助下虚拟颌位引导儿童关节强直患者同期矫治颌骨畸形的可行性。方法:回顾2016年1月至2017年6月于北京大学口腔医院颌面外科接受手术治疗的儿童颞下颌关节强直患者。将患者颌骨与牙列的影像数据导入计算机软件,进行虚拟设计,完成肋骨肋软骨移植和颌骨畸形的同期矫治,设计制作数字化咬合导板备用。术中完成关节强直松解后,在数字化咬合导板的引导下使下颌骨就位,并完成肋骨移植。对术前和术后即刻的颏点偏斜程度以及下颌升支高度进行测量,并对测量结果进行统计学分析,评价该方法的可靠性。结果:5例患者符合纳入标准,术前设计的虚拟颌位下颏点至面中线的距离平均为(0.58±0.20) mm,术后测量值为(0.70±0.27) mm,二者差异无统计学意义。虚拟颌位下患侧下颌升支的长度平均为(48.19±3.20) mm,术后测量值为(48.17±3.62) mm,二者差异无统计学意义。结论:在计算机辅助设计的虚拟颌位引导下,能够在重建关节的同时实现颌骨畸形的同期矫治。

Application of computer-aided virtual mandibular position in the simultaneous treatment of children with temporomandibular joint ankylosis and jaw deformity

Objective: To evaluate the feasibility of computer-aided design virtual mandibular position in the simultaneous treatment of children with temporomandibular joint ankylosis (TMJA) and jaw deformity. Methods: The children with unilateral TMJA were surgically treated from January 2016 to June 2017 in the Department of Oral and Maxillofacial Surgery. The image data of jaw and dentition were imported into the computer software to simulate the surgical procedure. An osteotomy of the affected side was performed to remove ankylosed bone mass. Then the mandible was rotated around the unaffected condyle to eliminate the chin deviation by the virtual plan. An open bite was thus created on the affected side to provide space for vertical midfacial growth. In the virtual mandibular position, the affected ramus was reconstructed with costochondral grafting. Finally, digital occlusal splint was designed and pre-fabricated by 3D printing. During surgery, temporomandibular joint ankylosis was released and mandibular position was guided in place by the digital occlusal splint. In the new mandibular position, costochondral grafting was completed. After the surgery, the occlusal splint was wired to the mandibular dentition and would be gradually adjusted by grinding off the maxillary side to promote downward growth of the maxilla until the open bite was eliminated. The ramus height and chin deviation were measured before and one week after the surgery to validate the method. Comparisons of the measurements were made by means of a repeated-measures analysis of variance (ANOVA) (P=0.05). Pair-wise multiple comparisons were conducted using the Bonferroni correction (P=0.05). Results: Five patients were included in this study. Under the guidance of the digital occlusal splint, the mandible could reach the preoperative designed position smoothly in all the cases. The chin deviations were (0.58±0.20) mm in the virtual plan before surgery, and (0.70±0.27) mm after surgery, which were not significant statistically (P>0.05). The ramus heights on the affected side were (48.19±3.20) mm in the virtual plan before surgery, and (48.17±3.62) mm after surgery, which were not significant statistically (P>0.05). Conclusion: It is feasible and reliable in the simultaneous treatment of TMJA with jaw deformity under the guidance of virtual mandibular position.