OBJECTIVE: To evaluate the social smile symmetry using three-dimensional (3D) stereophotogrammetric images. MATERIALS AND METHODS: The study was conducted with 3D facial images of 30 individuals (age range 13-25 years). The rest position was considered as the reference image and the social smile image was aligned on this image using the best-fit alignment method. The spatial differences between the same points established on both images using 3D analyses were determined for right and left points in X, Y, and Z planes. RESULTS: The highest difference related to spatial distance in right and left points was -0.56 mm (95% confidence interval [CI], -1.19, 0.06 mm) between right and left commissure (Com) points. The difference was not significant, and the Bland-Altman upper and lower limits were -3.85 mm and 2.71 mm, respectively. The highest difference for the transversal plane was found in Com points, similarly to the spatial distance (mean: 0.50 mm, 95% CI, -2.62, 1.02 mm). The differences between the changes in the left and right points in the Y and Z plane were not significant (P > .05). CONCLUSIONS: The social smile was observed to show asymmetry in varying amounts in the different directions. Asymmetry increases in some cases, specifically for the corners of the mouth.
OBJECTIVE: To evaluate the social smile symmetry using three-dimensional (3D) stereophotogrammetric images. MATERIALS AND METHODS: The study was conducted with 3D facial images of 30 individuals (age range 13-25 years). The rest position was considered as the reference image and the social smile image was aligned on this image using the best-fit alignment method. The spatial differences between the same points established on both images using 3D analyses were determined for right and left points in X, Y, and Z planes. RESULTS: The highest difference related to spatial distance in right and left points was -0.56 mm (95% confidence interval [CI], -1.19, 0.06 mm) between right and left commissure (Com) points. The difference was not significant, and the Bland-Altman upper and lower limits were -3.85 mm and 2.71 mm, respectively. The highest difference for the transversal plane was found in Com points, similarly to the spatial distance (mean: 0.50 mm, 95% CI, -2.62, 1.02 mm). The differences between the changes in the left and right points in the Y and Z plane were not significant (P > .05). CONCLUSIONS: The social smile was observed to show asymmetry in varying amounts in the different directions. Asymmetry increases in some cases, specifically for the corners of the mouth.
Keywords:
3D stereophotogrammetry; Social smile; Symmetry
Authors: María Melo; Javier Ata-Ali; Fadi Ata-Ali; Marco Bulsei; Perluigi Grella; Teresa Cobo; José María Martínez-González Journal: BMC Oral Health Date: 2020-02-06 Impact factor: 2.757