Effect of Overall Facial Convexity on Lip Profile Preferences

The lip profile can be influenced by positioning of the incisors during orthodontic treatment and is therefore an important consideration during the treatment planning process. Objectives: The purpose of this study was to determine the influence of mandibular position on the preferred lip profile fullness. Methods: 5 digitally created male and female facial profiles ranging in convexity (g-sn-pg) between -25° and +3°, were presented to orthodontists (n=40), patients (n=40) and parents of patients (n=40). Evaluators were asked to move the upper and lower lips on a computer screen to the fullness they preferred. Lip positions chosen, relative to the e-line, were recorded and compared among facial profiles, among evaluator groups, and between male and female evaluators for both male and female profiles. Results: Comparisons made using ANOVA showed that evaluators preferred significantly more full lips for the -25° profile, followed by the -18° & +3° profiles, and least full lips for the -11° & -4° profiles (p<0.0001). There were no significant differences in preferences among evaluator groups or between male and female evaluators (p>0.20). There were only scattered and inconsistent differences found between lip preferences for male and female profiles. Conclusion: Overall facial convexity and specifically mandibular position should be considered when determining ideal lip position during orthodontic treatment planning. More full lips appear to be preferable for patients with more extreme degrees of retro- or prognathism. This study was supported in part by a grant from the Southern Association of Orthodontists, an Alexander Fellowship, and the MCV Orthodontic Education and Research Foundation.