Abstract
Loading on the temporomandibular joint while clenching in several occlusal conditions is important to determine the cause of craniomandibular dysfunction.
In this study, the condylar displacement was measured while clenching in the intercuspal position in two groups and evaluated the loading from this measurement. Group 1 (G1) was twenty subjects with complete dentition and normal occlusion. Group 2 (G2) was seven subjects with a unilateral posterior bridge; the condylar displacement of each subject was measured for the cases with occlusal contact (OC) and those without OC by removal of the bridge. Condylar displacement was measured by lateral transcranial radiographs.
Condylar displacement while clenching in G1 averaged 0.1±0.2mm posteriorly, 0.2±0.2mm superiorly. The directions of condylar displacement varied from anterosuperiorly to posterosuperiorly. The variety of these directions may have a relationship with the portion of morphological change of condylar remodeling.
In the case of G2, the average values of condylar displacement with OC were the same as the displacement in G1. Therefore, it is considered that the bridge does not influence condylar displacement. No significant difference was observed between the subjects with and without unilateral OC in condylar displacement while clenching. This result suggests that the reduction of unilateral OC has little effect on condylar displacement while clenching.
