Craniofacial Morphologic Characteristics Of Angle â…¡ Division 2 Malocclusion In Permanent Dentition

Objective: To investigate the difference of craniofacial hard tissue between angle â…¡2and angle I malocclusion in permanent dentition with cephalometrics and obtain the craniofacial characteristics ,malocclusion mechanism and development rule of angle â…¡2 for guilding the clinical practice. Methods: 60 examples with angle â…¡2and other 40 patients at similar mean age with angle I in permanent dentition were selected . cephalometric landmarks were marked on each patient's lateral head film.36 lateral cephalometric variables and 6 model analysis variables which were associated with angle â…¡2were evaluated to obtain the significant different measurements and find most important factor which affect the overbite depth of angle â…¡2with the method of multiple linear regression. Results: Sagittal skeletal parameters are shown without diffrence significantly in maxillary, but 6 sagittal variables are described with statistic significant in mandible between angle â…¡2 and angle I. With respect to the intermaxillary relationship, in the present study ,3 items are discriminate parameters between the two groups. However, 6 variables difference in the vertical dimension were found. The results of the present study demonstrate 6 variables with difference significantly in dentoalveolar parameters. 5 variables in cranial base and 1 variable in width dimension were found significant difference. Conclusion:Angle â…¡2maloccllusion has not only a pathognomonic dental appearance but also several skeletal sagittal ,and especially vertical attributes that differentiate it from Angle I. (1)the deep bite characteristic of Angle â…¡2 malocclusion is more skeletal than dentoalveolar, so advocate preorthodontics. (2)It is a auxiliary way to treat Angle â…¡2 which is not severe crowd with lower arch expansion . (3)The lower incisor to mandibular plane (LI--MP)distance is normal, so it's unreasonable to treat deep bite by intruding the lower incisor. (4)The treatments of deep bite of Angle â…¡2 mainly depend on orthognathic surgery to reprove the class â…¡occlusion relationship and rectify the overbite. Proclining the upper/lower incisor and expanding the lower arch are only auxiliary therapy method.