Assessment of the impact of fixed functional appliances on airway in patients receiving orthodontic treatment: A systematic review

Abstract

Introduction: Mandibular deficiency-related Class II malocclusion is widely recognized as a potential risk factor for upper airway sleep disorders such as Obstructive Sleep Apnea (OSA), as it can compromise the oropharyngeal airway. Several studies have indicated that functional appliances, commonly used to correct Class II malocclusions, may help to increase airway dimensions, thereby reducing the risk of respiratory issues. This systematic review aims to evaluate the effectiveness of fixed functional appliances on airway dimensions in patients undergoing orthodontic treatment. Material and Methods: A total of 19,400 articles were identified through four search engines (PubMed, Medline, Cochrane Library, Google Scholar, and clinicaltrials.gov). After applying the inclusion criteria, 10 studies were selected for analysis. The studies included were human clinical trials, covering randomized controlled trials (RCTs), controlled clinical trials (CCTs), observational studies, and both prospective and retrospective studies. Studies were included if they provided clinical data on the effectiveness of fixed functional appliances on airway dimensions in orthodontic patients. Only studies published between January 2000 and March 30, 2023, were considered. Results: The analysis revealed that fixed functional appliances have a positive impact on airway dimensions in patients undergoing orthodontic treatment, particularly those with retrognathic mandibles. Significant enlargement of the airway was observed, predominantly in the oropharyngeal and hypopharyngeal regions, while the nasopharyngeal region showed comparatively smaller changes.