Sagital position of glenoid fossa in Angle Class II malocclusion with mandibular retrusion.

PURPOSE: To evaluate and compare the morphology, and position of the glenoid fossa in patients with Class Il malocclusion associated with mandibular retrusion and Class I malocclusion in the permanent dentition. METHODS: A sample of 26 subjects (12 males, 14 females, average age 13.4 years) with skeletal and dental Class II malocclusion associated with mandibular retrusion, was compared with a matched group of 31 subjects(12 males, 19 females, aged 12.9 years) with skeletal and dental Class I relationships. The lateral cephalograms were traced and the cephalometric analysis was taken by Nemotec Dental Studio 2006 software before orthodontic treatment. The comparisons between the two groups on the cephalometric measures for the assessment of glenoid fossa were performed by means of an independent samples t test using SPSS 15.0 software package. The correlation and regression analysis was also performed within the measures in the Class II group. RESULTS: The results showed there was significant difference of Wits, GF/Ptm-FH and GF-FMN between the two groups (P<0.01). There was a significant correlation between the GF-FMN vs. AOBO, GF-FMN vs. GF/S- FH, GF/S-FH vs.GF/Ptm-FH, S/Ptm-FH vs. GF/Ptm-FH in the Class II group. The regression equations of the GF-FMN vs. AOBO and GF-FMN vs. GF/S-FH were also obtained (P<0.05). CONCLUSIONS: The Class II malocclusion associated with mandibular retrusion patients have a posteriorly displaced glenoid fossa compared with Class 1 patients. Cephaiometric measurement is a useful tool to evaluate the glenoid fossa morphology and position. Supported by Research Fund of Science and Technology Committee of Shanghai Municipality (Grant No.08DZ2271100). [ABSTRACT FROM AUTHOR]