Upper Lip Asymmetry During Smiling: An Analysis Using Three-Dimensional Images

Özet

Objective: The aim of this study was to use three-dimensional images to determine the presence of upper lip asymmetry at rest andduring smiling in a group of individuals with no history of orthodontics or facial cosmetic surgery.Methods: Standardized three-dimensional frontal resting and smiling images of 54 volunteers were analyzed using the 3dMDvultussoftware (3dMD, Atlanta, GA). Measurements were made from the soft tissue nasion, ipsilateral ala, subnasale, and menton to theright and left commissures of the lip. A 2.5 mm or greater difference between the right and left sides was defined as an asymmetry.The agreement on the presence or absence of asymmetry between the subjects’ states of rest and smiling was determined by theMcNemar’s chi-squared test. Statistical significance was defined as p<0.05.Results: Menton was the most stable facial landmark to evaluate the upper lip symmetry at rest and during smiling (p=0.002). Usingmenton as a landmark, only one of the 54 subjects showed asymmetry while resting, but 12 (22%) showed asymmetry when smiling.Conclusion: As part of treatment planning for orthodontics or orthognathic surgery, patients should be evaluated for the upper lipsymmetry during resting and smiling. The presence of asymmetry during smiling is a significant clinical problem that needs to berecognized so that patients can be informed about the effect it can have on the final esthetic result.