For The Teeth Of Skeletal Class ¢ó (occlusal) Craniofacial Morphology Study

To investigate the difference of craniofacial hard and soft tissue between skeletal Class â…¢ malocclusion and normal occlusion in mixed dentition and speculate its etiologic factors. [Methods] 38 children with skeletal Class â…¢ malocclusion in mixed dentition were selected as a sample group, other 40 children at similar mean age with normal occlusion were selected as a control group. 81 lateral cephalometric variables which are associated with Class â…¢ hard and soft tissue were evaluated by using CRAS computer system . [Results] In linear analysis of hard tissue, 13 variables in male and 12 variables in female are significantly different between the sample group and the control group. 5 variables in the ratio of linear measurement and 20 variables in angular measurement of hard tissue were found significantly different between the two groups . In linear analysis of soft tissue, 13 variables in male and 12 variables in female are significantly different between the two groups. Significant difference between two groups also exists in 9 angular variables of soft tissue. [Conclusions] A trend of backward displacement and hypoplasia were found in maxilla. Mandibular hyperplasia is the main factor which is responsible for Class â…¢ malocclusion. Morphologic changes of mandible and anterior positioning of the glenoid fossa make intermaxillary discrepancy more serious. Some changes of soft tissue can compensate for the underlying skeletal discrepancy but other changes exacerbate the facial disharmony.