单侧后牙反者髁突开闭口运动轨迹的研究

目的通过记录单侧后牙反(牙合)者与正常牙合者下颌开闭口运动时髁突在三维方向上的运动轨迹,探讨单侧后牙反(牙合)者髁突开闭口运动轨迹的特征,揭示其与正常(牙合)之间的差异.方法对照组选取正常(牙合) 5人,实验组选取单侧后牙反(牙合)者7人,应用计算机化的髁突运动轨迹描记仪(computer-aided axiography, CADIAX)Ⅰ型以及分析软件(gamma dental software for Windows 2.3.2.22,GDSW)记录下颌做最大开闭口运动时髁突在水平面及矢状面上的运动轨迹.结果①单侧后牙反(牙合)者开闭口矢状向最大位移量显著小于正常对照组;②实验组开闭口运动轨迹在矢状面上表现出小年龄患者双侧基本对称、大年龄患者双侧轨迹不对称;③实验组开闭口运动轨迹水平侧向移动量均大于正常对照组.结论单侧后牙反(牙合)者髁突开闭口运动轨迹与正常(牙合)者有显著差异,随着年龄增大,反(牙合)侧与反(牙合)对侧轨迹由对称向不对称发展,表现出一定的代偿和失代偿的特征.

Study of the tracings of the condylar movements during opening/closing of the unilateral posterior crossbite

Objective To discuss the influence of dental occlusion on mandibular movements. The characteristic tracings of mandibular movements at the condyle of unilateral posterior crossbite patients were investigated using a computerized axiography. The differences between patients with normal occlusion and unilateral posterior crossbite were compared by some recordings of condylar movements in three dimensions. Methods Seven unilateral posterior crossbite patients (at least two posterior teeth were crossbite) were chosen as experiment group, and five with normal occlusion without signs or symptoms of temporomandibular disorders (TMD) were chosen as controls. By computer-aided axiography (CADIAX) and gamma dental software for windows 2.3.2.22 (GDSW) from Grbh company (Germany), the tracings of condylar movements in right and left parasagittal planes during opening/closing were recorded, and the data were input into the computer and analyzed using GDSW software. The drifts in X, Y and Z coordinated with condylar movements, respectively, and the transverse condylar inclination from the orbital axis line and the horizontal condylar inclination were calculated, respectively. Results The lengths of the axiographical in opening/closing movement were significantly shorter in the experiment group than that in normal occlusion group; the bilateral condylar tracing of opening/closing movement was symmetric in younger cases but asymmetric in older cases; the lateral deviation of opening/closing movement was significantly larger in unilateral posterior crossbite than that in control group. Conclusion The condylar tracings of envelope of movement in unilateral posterior crossbite patients are significantly different in the patients with normal occlusion. With age increasing, tracings of the affected side and contralateral side vary from symmetry to asymmetry. The results suggest that the functional opening movements are limited in the patients with the unilateral posterior crossbite.