The Relationship Between Airway Obstruction and Malocclusion Prevalence: A Systematic Review

Abstract Aim: To determine whether airway obstruction increases the prevalence of malocclusion in children aged 0–18 years. Materials and Methods: Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020, PubMed, Web of Science, and Scopus were searched from inception to April 2024 using predefined terms. Two reviewers independently screened titles/abstracts and full texts with third-reviewer arbitration as needed; data were extracted in duplicate, and risk of bias was assessed using the Newcastle–Ottawa scale. Due to substantial heterogeneity in populations, definitions, and outcome measures, no meta-analysis was performed, and results were synthesized narratively; numerical figures in the abstract refer to individual studies and are not pooled estimates. Results: Seven observational studies were included, comprising 3689 children. Overall, airway obstruction was associated with a higher prevalence of malocclusion; one hospital-based study (D’Ascanio 2010, n = 196) reported posterior crossbite at 48.0% in mouth breathers versus 3.1% in nasal breathers, and another study (Souki 2009, n = 401) reported Angle Class II at 66.3% versus 17.3%. Adenoid/tonsil hypertrophy was the most common condition; one community-based study (Tong 2022, n = 715) found no clear dose–response relationship between tonsil size and malocclusion. All numerical values are study-specific and not pooled estimates; no meta-analysis was performed. Conclusion: Airway obstruction is strongly associated with posterior crossbite and Class II malocclusion in children. Screening for malocclusion in children with documented structural obstruction may be warranted during active growth. However, evidence supporting the therapeutic benefit of airway treatment for preventing malocclusion is absent; intervention studies are needed before treatment recommendations can be made. Emerging technologies and theoretical frameworks offer promising avenues for precision diagnosis and personalized treatment approaches.