[Polysomnographic and clinical characteristics analysis of children with different types of malocclusion]

Objective: To explore the polysomnography characteristics of different types of malocclusion in children. Methods: We retrospectively analyzed the clinical data of 763 school-age children with malocclusion who visited the Department of Orthodontics, Wuhan University School and Hospital of Stomatology and the Department of Otolaryngology-Head and Neck Surgery, Zhongnan Hospital of Wuhan University from January 2022 to December 2024. Among them, there were 393 males and 370 females, with an average age of 8 (range, 7-9) years.CBCT, electronic nasopharyngoscopy, and overnight polysomnography were collected. For the sagittal skeletal pattern, the skeletal patterns were categorized into Angle Class Ⅰ, Angle Class Ⅱ, and Angle Class Ⅲ according to the ANB angle. For the vertical dimension, classification was based on the ∠SN-MP angle, dividing the patients into low-angle, average-angle, and high-angle skeletal patterns. We compared the differences in various PSG indicators such as obstructive apnea-hypopnea index (OAHI), sleep efficiency (SE), proportion of rapid eye movement sleep (REM), respiratory-related micro-arousal index, and average and maximum heart rates during sleep among different groups. Also, we conducted a multiple linear regression analysis to explore the independent correlation between skeletal patterns and PSG characteristics. Results: In school-aged children, regarding sagittal skeletal patterns, compared with Class Ⅰ [1.0 (0.4, 2.0) events/h], children with Class Ⅱ [1.3 (0.6, 2.3) events/h] and Class Ⅲ [1.4 (0.5, 2.8) events/h] showed higher OAHI values (P<0.001), higher respiratory-related microarousal indices, and lower SE and REM sleep percentage (all P<0.001). Regarding vertical skeletal patterns, children with a high-angle facial pattern [2.1 (1.0, 4.5) events/h] had higher OAHI than those with low-angle [1.1 (0.5, 2.1) events/h] and average-angle facial patterns [1.2 (0.6, 2.0) events/h] (P<0.001), as well as a higher respiratory-related microarousal index, while, SE and REM sleep percentage were lower (all P<0.001). In addition, children with Class Ⅱ, Class Ⅲ, and a high-angle facial pattern generally had higher mean and peak heart rates during sleep (all P<0.001). After adjustment for potential covariates, multivariable linear regression analysis further confirmed the significance of these differences. Conclusion: Skeletal patterns in school-age children with malocclusion partially influence their sleep breathing characteristics, particularly in terms of the OAHI, SE, percentage of REM sleep, respiratory-related arousal index, and average and maximum heart rates during sleep. Children with Class Ⅱ, Class Ⅲ, and high-angle skeletal patterns are at higher risk for sleep-disordered breathing, suggesting that skeletal pattern should be considered in the early diagnosis and intervention of pediatric sleep respiratory disorders.