Chin Morphology in Subjects with Different Vertical Skeletal Craniofacial Pattern

Objective To evaluate whether there is difference with regard to chin morphology in subjects with different vertical skeletal craniofacial pattern and the relationship among them.Methods The sample was composed of 80 adolescents who denied orthodontic treatment history and presented ClassⅠskeletal pattern,aged(12.69±0.70) years.They were divided into three groups according to mandibular plane angle: High angle group(21 cases,FH/MP≥ 32°),average angle group(43 cases,22°FH/MP32°) and low angle group(16 cases,FH/MP≤22°).Cepholagrams were taken and cepholametrics was employed.Both vertical and horizontal craniofacial pattern were evaluated.In addition,chin dimensions studied included height,depth,ratio(depth/height),angle,and so on.They were compared betweendifferent groups with One-Way ANOVA.Correlation was analyzed between vertical skeletal craniofacial pattern and chin morphology.Results SNA,SNB and ANB presented no significant difference among three groups.Compared with the low angle group,high angle subjects exhibited increased chin height,depth/height ratio,concavity and decreased chin angle.Therefore the chin looked lathier and less protrusive in high angle group.Positive correlation was found between mandibular plane angle and chin height,concavity,curvature(P0.05),negative correlation between mandibular plane angle and chin minimal depth,depth/height ratio,angle.Conclusion Difference emerged with regard to chin morphology in subjects with different vertical craniofacial skeletal pattern,which deserves to be taken into consideration in orthodontic treatment planning.