Effect of non-surgical maxillary expansion on the nasal septum deviation: a systematic review

Nasal breathing is a requirement for proper growth and development of the craniofacial complex. Inadequacy of the nasal airway from obstruction such as from nasal septal deviation (NSD) can affect craniofacial development. Further investigation of the possibility of rapid maxillary expansion (RME) correcting NSD would be valuable, considering the undesirable sequelae of NSD on nasal breathing, which can consequently affect craniofacial development. A systematic review of the effect of RME treatment on NSD was conducted. Electronic database searches were conducted until April 2015 using MEDLINE, EMBASE, Web of Science, Cochrane Database of Systematic Reviews (CDSR), Cochrane Central Register of Controlled Trials (CCTR), Cochrane Methodology Register (CMR), Database of Abstracts of Reviews of Effects (DARE), American College of Physicians Journal Club (ACP Journal Club), Health Technology Assessments (HTA), and NHS Economic Evaluation Database (NHSEED). MeSH terms used in database searches were 'nasal septum,' 'palatal expansion,' and 'maxillary expansion,' 'orthodontic device,' and 'palatal expansion technique.' The methodological quality of studies was reviewed using methodological index for non-randomized studies (MINORS). Only two studies were finally selected and reviewed. Both studies had significant methodological limitations. One study reported a significant straightening of the nasal septum in the middle and the inferior third of nasal cavity from RME in children aged 5 to 9 years. The other study reported no positional change in the nasal septum from RME in adolescent orthodontic patients. Thus far, the limited available (moderate risk of bias) evidence suggests a potentially positive effect on the nasal septum asymmetry during childhood, but no significant change in adolescence from RME in patients with NSD. The clinical significance of reported changes could be considered questionable.