种植体型功能矫治器对颅面部生长作用的三维结构分析

目的:从三维CT重建角度,探讨种植体型功能矫治器对颅面部生长的作用.方法:11只雄性、7个月龄、混合牙列晚期的Beagle犬,随机分为种植体型功能矫治器组、半种植体型功能矫治器组、改良ForsusTM组以及正常对照组.分别在戴用矫治器4、8、12周和去除矫治器后4周,用螺旋CT扫描Beagle犬颅面部以获取数字信息,再用Mimics 8.1软件和逆向工程软件qualify V8.0,建立Beagle犬颅面部硬组织三维图像,采用前颅底部结构和下颌骨种植体重叠法,分析各组不同阶段颌骨及牙的三维结构变化.结果:种植体型功能矫治器、半种植体型功能矫治器和改良型ForsusTM矫治器组Beagle犬下颌骨的向前生长明显,而上颌骨则受到一定程度的生长抑制.种植体型功能矫治器组实验后,犬上颌骨牙列移动不明显,而半种植体型功能矫治器和改良型ForsuTM矫治器组犬上颌牙列出现明显远中移动.结论:种植体型功能矫治器能显著促进下颌生长,不会导致牙的不利移动.

Assessment of facial skeletal growth and response to implanted functional appliance therapy with three-dimensional images

PURPOSE: To evaluate the facial skeletal growth and response to implanted functional appliance therapy with three-dimensional images. METHODS: Eleven male Beagle dogs (7 months old and in late mixed dentition) were randomly divided into four groups: implanted functional appliance group, semi-implanted functional appliance group, modified Forsus(TM) group and the control group. After the appliances were inserted in the experimental groups for 4, 8, 12 weeks and 4 weeks after the appliances were removed, the facial skeleton and teeth of the Beagle dogs digital information was obtained by using spiral computed tomography, then Mimics 8.1 software and a kind of retro-engineering software called qualify V8.0 were used to establish three-dimensional facial skeletal and dental images of the Beagle dogs. Three-dimensional structure changes of the facial skeleton and teeth in each group at different stages were assessed by the Bjork method, i.e. the superimposition technique based on the "best fit" of anterior cranial base structure and mandible metallic implants. RESULTS: Mandibles in the groups with implanted functional appliance, semi-implanted functional appliance, and modified ForsusTM were obviously displaced forward, while the growth of the maxilla was inhibited in some degree. The displacement of upper teeth in the group with implanted functional appliance was not obvious, while the distal movement of upper teeth in the group with semi-implanted functional appliance and modified ForsusTM was significant compared with that in the control group. CONCLUSIONS: The implanted functional appliance can significantly stimulate the growth of the mandible and avoid the unwanted movement of teeth which is frequently found in other functional appliances. Supported by Wenzhou International Cooperative Research Project (Grant No. B00260027).