The upper airway dimensions in different sagittal craniofacial patterns: a systematic review

OBJECTIVE. Upper airway changes caused by orthognathic surgery operations have been a topic of a concern in the orthodontic literature because of a possible development of obstructive sleep apnea. Diverse response of the airway patency could be expected if the dimensions of the airway differ among various malocclusions already before orthognathic treatment. However the associations between facial morphology and the upper airway dimensions have not been clarified. The purpose of this systematic review was to elucidate whether the upper airway dimensions differ among various sagittal craniofacial patterns. MATERIAL AND METHODS. MEDLINE and the Cochrane Library were searched up to November 2012. Reference lists of relevant articles were checked for further possible studies. Strict inclusion and exclusion criteria were applied when considering the studies to be included. Screening of eligible studies and data extraction were conducted independently by two reviewers. RESULTS. 758 studies were identified and 11 of these were recognized as suitable for further analysis. 75% of studies did not find differences in the nasopharyngeal dimensions among craniofacial patterns. The findings for the oropharyngeal dimensions were controversial as 5 of 11 investigations found these to be smaller in Class II subjects, and 6 of 11 concluded that oropharynx size is larger in Class III pattern. The vertical growth type of the subjects was not considered in five investigations, and 45% of the included studies used lateral cephalometry as only tool for airway assessment. CONCLUSIONS. Currently there is insufficient evidence that the upper airway dimensions differ in various sagittal skeletal patterns.