Objective: The aim of this study is to evaluate changes in the upper airway in adult patients following orthodontic treatment.
Methods: For this study, pre- and post-treatment lateral cephalographs of 100 adults (Mean age; 42.9 ± 1.5 years: Mean treatment time; 21.3 ± 6.2 months) were scanned, and 27 landmarks encompassing the upper airway were digitized using appropriate software. The mean pre- and post-treatment upper airway configurations were computed using Procrustes superimposition, and analyzed using finite-element analysis (FEA).
Results: Using pseudo-colored FEA, a relative 22% increase in nasopharyngeal airway area was found above and behind the soft palate. As well, a 16% increase in oropharyngeal airway area was located behind the base of the tongue with a 13% increase in hypopharyngeal area near the level of the hyoid bone.
Conclusions: The upper airway changes in non-growing adults are similar to those of actively-growing children undergoing functional orthodontic corrections, and suggest that genetically-encoded developmental mechanisms can be modulated by orthodontic appliances to enhance the upper airway in adults. These findings may help in the management of adults diagnosed with obstructive sleep apnea.