Effects of Upper Curvature of Lower Lip on Smile Arc Esthetics

doi:10.13701/j.cnki.kqyxyj.2021.08.006

Abstract

Abstract: Objective: To study the proportion of patients with different upper curvatures of lower lip at the end of orthodontic treatment and the effect of different curvatures of smile arc on the smile esthetics in patients with V-shaped or trapezoidal upper curvature of lower lip. Methods: 300 patients were included in this study, and the distribution of different upper curvatures of lower lip was calculated. Different vertical distances between the central incisor and lateral incisor and different upper curvatures of lower lip were combined and compared by orthodontists, prosthodontists, and laypersons. Results: The proportion of patients with round, V-shaped, and trapezoidal upper curvature of lower lip was 54.7%, 23.3%, and 23.0%. For patients with V-shaped upper curvature of lower lip, the evaluators chose smile arc with 2mm vertical distance of the incisor edge between central and lateral incisors, while for the patients with trapezoidal upper curvature of lower lip, smile arc with flat curvature was chosen. Conclusion: The influence of upper curvature of lower lip on the smile arc esthetics should be fully considered when orthodontists make the treatment plan. For the patients with V-shaped upper curvature of lower lip, it should be cautious to intrude the maxillary anterior teeth, while for the patients with trapezoidal upper curvature, flat smile arc is recommended.

Key words: smile arc, lower lip curvature, esthetics, orthodontics, group assessment

DING Hong, WANG Wei, XU Hong, XIU Xia, JIANG Chunmiao. Effects of Upper Curvature of Lower Lip on Smile Arc Esthetics[J]. Journal of Oral Science Research, 2021, 37(8): 696-701.

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