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DOI

10.1016/j.jds.2025.06.009

First Page

2219

Last Page

2230

Abstract

Abstract Background/purpose Research regarding clinical facial assessment has increasingly shifted toward three-dimensional (3D) methods. This cross-sectional study examined the associations between 3D smile variables and two anteroposterior craniodentofacial morphologies (overjet [OJ] and point-A-nasion-point-B angle [ANB]) and quantified facial soft tissue displacement during the transition from rest to posed smiles. Materials and methods This study included 119 participants aged 18–30 years. They were divided into three OJ groups (0–4 mm, >4 mm, and <0 mm) and three ANB groups (0°–4°, >4°, and <0°). 3D facial images were taken at rest and during smiling. Subsequently, landmark positions were analyzed. Linear, angular, and proportional measurements were obtained, and landmark displacements were measured. Results Of the 257 3D soft tissue variables considered, 41 differed significantly among the 3 OJ groups, and 46 differed significantly among the 3 ANB groups during smiling. The intercommissural width measured during smiling in ANB group 1 was more significant than that in the other two groups. Labiomental angles were larger in ANB group 3 at rest and during smiling, whereas the angle at rest was smaller in OJ group 2. Lower lip movements in OJ group 3 and ANB group 3 were more restricted than those in groups 1 and 2. Conclusion OJ and ANB primarily affect soft tissue landmarks during smiling. A large OJ may lead to a deep labiomental sulcus, whereas a negative ANB may result in a flattened sulcus. Reverse OJ and Class III skeletal malocclusion affect the lower lip by restricting its movement.

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