Abstract:

Objective To study the lip contour of Class Ⅱ division 1 malocclusion in the early permanent dentition with different growth patterns and gender. Methods 145 patients with Class Ⅱ division 1 malocclusion in the early permanent dentition were included in this study. Their pre-treatment cephalometric X-rays were measured to analyze the influence of gender and growth pattern on the lateral lip contour. One-way analysis of variance was used to analyze the influence of growth pattern on the lip contour of patients in the early permanent dentition, and t-test was used to analyze the influence of gender on the lip contour of patients. Results The lip vertical extension values of male patients were larger than that of female（P<0.05）; the lip sagittal extension value of male seems to be larger too, but no significant difference was found（P>0.05）. The upper lip extension patterns of patients with different growth patterns were the same, but patients of horizontal growth pattern had more everted and protrusive lower lips than patients of vertical growth pattern. Conclusion Gender and growth pattern both have influences on the lip contour of Class Ⅱ division 1 malocclusion in the early permanent dentition.

Key words: Class Ⅱ division 1 malocclusion, lip contour, growth pattern, sexual dimorphism