Evaluation of the influencing factors on facial development for mouth breathing children: Insights from 3D scanning technology

Introduction: Mouth breathing is considered a predisposing factor for sleep breathing disorders which may affect facial morphology, this study investigated the effect of age, gender, and breathing pattern on children's facial morphological development. Material and methods: 3dMD system (3dMD Inc., Atlanta, GA, USA) was utilized to acquire 3D images of the face. A total of 195 children aged 7–12 years were divided into 12 groups by age (7–8 years group, 9–10 years group,11–12 years group,), gender, and breathing pattern (mouth breathing MB, nasal breathing NB). A total of nineteen linear, angle, and ratio measurements were performed. Independent t-tests, Mann-Whitney U tests, One-way ANOVA tests and Kruskal-Wallis test were used to compare between the groups. Linear regression was used to test the relationship between age, gender, breathing patterns and facial development. Results: In males, facial convexity angle (FCA) was significantly greater in the MB group than in the NB group in the 11–12 years age group (MB:17.82 ± 5.86, NB:13.24 ± 3.95, P = 0.023). In females, mandibular width increased with age only in the NB group (P < 0.01); in the 9–10 years group, FCA was greater in the MB group than in the NB group (MB:19.03 ± 5.99, NB:14.3 ± 4.59, P = 0.036). In the 11–12 year old group, the mandibular width was significantly smaller in the MB group (MB:111.11 ± 6.34, NB:117.07 ± 8.53, P = 0.026) than in the NB group. Age (P < 0.01) and gender (P < 0.01) were correlated with mandibular width. Additionally, age (P < 0.01), gender (P < 0.01) and respiratory mode (P < 0.05) were correlated with lower lip height. Discussion: The upper mid-part development of the face increased with age, and MB showed a more convex profile in males and a narrower mandible in females. The lower third of the facial development was correlated with age, gender, and breathing pattern. Furthermore, mouth breathing was correlated with limitation of mandibular development and increased lower lip height.