Three-dimensional Analysis Condylar Position And Midline Deviation Of Jaw Bones In Steletal Class ? Malocclusion With High Angle

Objective:The aim of this study was to evaluate the symmetry of bilateral condylar position,the relationship of condyle and glenoid fossa,the deviations of midline of the maxilla and mandible,and the correlation between the condylar position and the midline deviation of the maxilla and mandible in skeletal class ? malocclusions with high angle.Methods:Totally 45 cases CBCT with high angle steletal class ? malocclusions were chosen,and the scan data were imported to the software Mimics17.0.The deviations of midline of the maxilla and mandible(the displacement of ANS.anterior nasal spine and Me.menton from the mid-sagittal plane of the skull)and the condylar position(the angle between the long axis of the condyle and the mid-sagittal plane,the shortest distance between the center of the condyle and the mid-sagittal plane,the anteroposterior difference between the bilateral condylar position as reflected on the mid-sagittal plane,anterior joint space-AS,superior joint space-SS,posterior joint space-PS)were measured.Statistical analysis of measurements,the deviations of midline of the maxilla and mandible were compared,the symmetry of bilateral condylar position and the relationship of the condyle and glenoid fossa were evaluated,the correlation between the condylar position and the midline deviation of the maxilla and mandible were analysised.Results:The deviations of Me to the left or right is slightly larger when compared with the ANS.About the angle between the long axis of the condyle and the mid-sagittal plane,the shortest distance between the center of the condyle and the mid-sagittal plane,and AS?SS?PS,there were no statistically significant differences were found between the right and left condyles(P>0.05),and there were no significant correlation with the deviations of ANS and Me(P>0.05).But the angle between the long axis of the left condyle and the mid-sagittal plane has a correlation with the anteroposterior difference of the bilateral condylar position(P<0.05),and the correlation was found between anteroposterior difference of the bilateral condylar position and the deviations of ANS and Me(P<0.05).The position of bilateral condyle in the glenoid fossa is mainly centered,the right condyle accounted for 55.6% and the left condyle accounted for 51.1%.Conclusion:1.In skeletal class ? malocclusions with high angle,the midline deviation of mandible was more obvious than that of maxilla.2.In skeletal class ? malocclusions with high angle,the angle between the long axis of the condyle and the mid-sagittal plane,the shortest distance between the center of the condyle and the mid-sagittal plane,and the relationship of condyle and glenoid fossa were basically symmetrical and consistent,but the anteroposterior position of condyle may be asymmetrical.3.In skeletal class ? malocclusions with high angle,the right and left condyle were mostly in the medium position of the glenoid fossa.4.In steletal class ? malocclusions with high angle,the anteroposterior difference between the bilateral condylar position as reflected on the mid-sagittal plane has a significant correlation with the midline deviation of maxilla and mandible.