Study of the tracings of the condylar movements during opening/closing of the unilateral posterior crossbite / 西安交通大学学报(医学版)

ABSTRACT

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.