Table 1. Electronic databases search strategy (refer to S1 Text for detailed search strategy).

Electronic databases	Search strategy
PubMed	(Systematic review OR review OR overview OR meta-analysis OR evidence based medicine OR evidence based dentistry OR review literature OR literature review)
EMBASE	AND
Web of Science	(orthognathic surgery OR orthognathic surgical procedure OR orthodontics surgery OR maxillomandibular advancement OR mandibular surgery OR maxillary surgery OR bimaxillary surgery OR jaw surgery OR surgical orthodontic treatment OR jaw advancement OR jaw movement OR mandibular advancement)
Cochrane library	AND
Scopus	(upper airway OR pharynx OR pharyngeal OR oropharynx OR oropharyngeal OR nasopharynx OR nasopharyngeal OR hypopharynx OR hypopharyngeal)