Dynamics of salivary stress-related biomarkers in children with malocclusion and risk for sleep problems and sleep-disordered breathing: a cross-sectional study

INTRODUCTION: Sleep problems in children can affect neuroendocrine regulation and craniofacial development. Although malocclusion may contribute to airway impairment and altered growth patterns, the associations between sleep-related symptoms and physiological stress markers remain unclear. This study examined salivary stress-related biomarkers and craniofacial morphology in children with malocclusion who were at elevated risk for sleep problems and sleep-disordered breathing (SDB). MATERIALS AND METHODS: Seventy-five children aged 7-12 years completed the Japanese Sleep Questionnaire for Elementary Schoolers (JSQ-ES). Children with total scores ≥80 were classified as high risk for general sleep problems, and those with SDB subscale scores ≥10 as high risk for SDB. Unstimulated saliva was analysed for oxytocin, melatonin, cortisol, and chromogranin A. Lateral cephalograms were evaluated for 34 variables. Statistical analyses included Shapiro-Wilk, t-tests or Mann-Whitney U-tests, and Pearson's or Spearman's correlations (P < .05). RESULTS: Fourteen children (18.7%) were classified as high risk for general sleep problems and 38 (50.7%) as high risk for SDB. Oxytocin concentration was lower in the high-risk sleep problems group (P = .041) and correlated negatively with JSQ-ES total score (ρ = -0.250). No biomarker differences were observed by SDB risk. Children at high risk for sleep problems showed a greater mandibular plane angle, while higher SDB scores were associated with anteroposterior skeletal discrepancies. CONCLUSIONS: Children at elevated risk for general sleep problems showed reduced salivary oxytocin and greater vertical skeletal divergence, whereas those at elevated SDB risk exhibited anteroposterior craniofacial differences without biomarker alterations.