Association Between Upper Airway Passages and the Inter-Maxillary Relationship

Objective: The purpose of the present study was to investigate a possible association between the antero-posterior diameter (APD) of the upper airways passages and its volume with the sagittal and vertical relationship between the upper and lower maxilla. Methods: 45 patients (22 girls and 23 boys), eight to twelve years old, were involved in the study. A cephalic radiograph from each subject was used to skeletally classify each patient into either normo- (n=17), disto- (n=23) or mesio-occlusion (n=5) by means of the cephalometric angle point A-Nasion-point B (ANB). APD of the airway passages at the naso- and oro-pharynx were also measured on the radiograph. The volume of the upper airways was determined by a Rhinometer/Pharyngometer test (Eccovision, Sleep Group Solutions, North Miami Beach, Fl, USA). Data was analyzed by a one-tailed unpaired t-test and the level of confidence was determined at 95 per cent. Results: APD of the airway passages at the naso- and oro-pharynx was significantly smaller in those subjects classified as disto-occlusion compared with the normo-occlusion ones. Airway volumes were smaller in the disto-occlusion patients without reaching statistical significance, but were significantly smaller in mesio-occlusion subjects compared with normo-occlusion subjects. When vertical relationship was considered, subjects with a disto-occlusion associated with deep bite had a significantly smaller APD of the airway passages at the naso- and oro-pharynx, as well as significantly reduced upper airway volumes. Conclusion: The present results demonstrated that sagittal and vertical malocclusions can be associated with a smaller antero-posterior diameter of the airway passages at the naso- and oro-pharynx, as well as with a reduced volume of the upper airway passages. However, these results should be considered preliminary and the sample size should be increased to fully demonstrate the association reported here.