[Investigation on border mandibular movement of adolescent with angle III malocclusion in initial stage of permanent dentition].

OBJECTIVE: To investigate characteristics of the border mandibular movement of the adolescent with Angle III malocclusion and to find the correlations between craniofacial morphology and border mandibular movement function. METHODS: The subjects consisted of 21 adolescent patients with Angle III malocclusion in the initial stage of permanent dentition (mean age 12.3 years). 20 adolescents with individual normal occlusion served as control (mean age 12.8 years). The border mandibular movement of all cases in the two groups were traced and recorded by K6-1 Evaluation System and standardized lateral cephalograms were taken. RESULTS: The results revealed no significant difference in the maximal movement range between two groups, but indicated a positive association between the maximum jaw opening and both the mandible length (Go-Gn) and the L1-MP. The distance from ICP to maximal opening (D) was positively correlated with facial height and the L1-MP. While to adolescents with individual normal occlusion, the wider the maximal jaw opening was, the bigger the posterior facial height and the cephalometric values of mandibular ramus. The distance D positively correlated with the anterior lower facial height. CONCLUSION: Angle III malocclusion had its characteristics in the tracing and had a specific relationship with the craniofacial morphology.