[Analysis of mandibular position of patients with angles Class I and Class II, division 1 malocclusion].

OBJECTIVE: To study changes of condyle position and occlusion between centric jaw relation and maximum intercuspation positions. METHODS: The power centric registration advocated by Roth was used to take centric relation bite registration for 50 patients (25 Class I and 25 Class II, Division 1) and diagnostic models were mounted and analysed with Panadent articulator and condyle position indicator. RESULTS: Nearly all patients had CR-MI differences in all three planes of space. 70% of the sagittal displacement was within 2.0 mm and 87% of the transverse displacement was within 1.0 mm. Most of the condyles moved posteriorly and inferiorly. 65% of the initial contacts in CR occured on the most posterior molar on single side. Correlation was found between some variables of condylar displacement and occlusion changes. No significant difference was observed in condylar position and occlusion changes between Class I and Class II, Dvision 1 patients. CONCLUSIONS: The occlusion in centric jaw relation should be analysed before treatment to reveal the disharmony between occlusion and jaw position.