Evaluation of the effect of using forsus, monoblock (activator) and class ii elastics to the temporomandibular joint position

Aim: It is thought that mechanics, used in the treatment of Class II malocclusions and changes the position of mandible, have effetcs on the temporomandibular joint. The aim of this study, to evaluate the effects of forsus, monoblock (activator) and class II elastics to the position of the temporomandibular joint by dinamic methods. Material and Method: Our study group included 75 patients who applied to Dicle University, Faculty of Dentristry, Department of Orthodontics. 20 of them were selected for forsus appliance group, 35 of them were selected for monoblock (activator) group and 20 of them were selected for class II elastics group. All of the patients were in growth period and had class II malocclusion. Centric relation (CR) and centric occlusion (CO) bite registration records were taken from the patients according to Roth's Power Centric Method before treatment, after treatment and approximately 6 months later from the treatment. Study casts were mounted on SAM-2 articulator at the position of centric relation. By using Mandibular Position Indicator (MPI), amount of centric discrepancy was measured. Discrepancies ≥2 mm in sagittal and vertical direction and ≥0,5 mm in transverse direction was accepted out of physiological boarders. Also, cephalometric radiographs were taken from the patients to compare the skeletal and dental changes of treatment procedures. Results: Among 75 patients, 72 of the patients (96%) had CR-CO discrepancy and 3 of the patients (4%) had CR-CO coincidence. It was found that dominant direction of the mandible was backward and downward. Cephalometric changes were detected after using of class II mechanics. Conclusion: The number of patients who were out of physiological boarders decreased at the end of the treatment and condyle movements occured in the physiological boarders. Mechanics that we used generally had a reducing effect on the centric discrepancy. The most effective mechanic that reduced the centric discrepancy was monoblock aappliance. It was observed that direction of centric discrepancy changed according to the treatment periods. Keywords: Centric Relation, Centric Occlusion, Power Centric, Temporomandibular Joint, MPI.