Three-dimensional upper airway changes with mandibular advancement device in patients with obstructive sleep apnea.

INTRODUCTION: A mandibular advancement device effectively increases upper airway size in patients with obstructive sleep apnea. Three-dimensional volumetric upper airway changes, exact amounts of change in obstructed upper airways (smallest cross-sectional area), and anteroposterior and transverse changes with mandibular advancement devices are not clear. METHODS: Thirty-seven patients with obstructive sleep apnea diagnosed with polysomnography were evaluated with the subjective Epworth sleepiness scale, percentage of oxygen saturation, and cone-beam computed tomography. Parameters were airway volume, smallest cross-section area, anteroposterior width, and transverse width of the upper airway. Patients received a mandibular advancement device, a Twin-block appliance that could be titrated with a jackscrew; posttreatment data were collected after 6 months. RESULTS: A statistically significant improvement in mean oxygen saturation level was observed, from 87.97% +/- 4.43% to 94.89% +/- 1.54% (P <0.001). A significant mean increase in airway volume of 2360 +/- 2050 mm(3) (P <0.001) was observed, from 12140 +/- 4773 mm(3) to 14500 +/- 5114.6 mm(3). A stastistically significant mean increase in the smallest cross section of 46.55 +/- 31.62 mm(2), from 81.95 +/- 55.23 mm(2) to 128.5 +/- 54.78 mm(2) was observed. Anteroposterior width increased significantly, from 4.99 +/- 1.65 mm to 8.01 +/- 2.04 mm. Transverse width increased significantly, from 27.67 +/- 8.52 mm to 31.94 +/- 8.59 mm. CONCLUSIONS: Mandibular advancement devices increased the mean upper pharyngeal airway volume in this cohort, and this increase in volume appeared to be related to increased oxygen saturation.