Abstract: Objective: This study used 3D scanning technology to explore the morphological characteristics of the facial soft tissue in mouth-breathing children. Methods: 81 children aged 10-12 years, 42 children with mouth breathing, and 39 children with nasal breathing, 3dMDFace system was used to obtain three-dimensional facial images, and a total of 18 measurement values were obtained, including linear distances, angles, and ratios. Subjects were grouped by gender, measures were compared using Independent sample t-test and Mann Whitney u test, and binomial logistic regression was used to verify the correlation between facial features and breathing patterns. Results: For males, mouth breathing had significantly smaller nasolabial angle compared with nasal breathing (p<0.05). Regarding the female group, mouth breathing compared to their nasal breathing counterpart had significantly decreased values in the mandibular width; the ratio of the mandibular width to the sum of the upper facial height, and the upper and lower lip height; and the ratio of the mandibular width to the sum of the upper and lower lip height (p<0.01). Besides significantly increased value in the ratio of lip width to mandibular width (p<0.05). Logistic regression results showed that nasolabial angle, and mandibular width were correlated with mouth breathing(p<0.05). Conclusion: Mouth-breathing children showed narrower mandibular width and more protruded upper lip.

Key words: Mouth breathing , Nasal breathing , Facial soft tissue, Nasolabial angle