Abstract
The objective was to determine whether hyoid bone elevation induced by an anterior mandibular positioning appliance (AMP) predicts the effectiveness of the AMP in patients with obstructive sleep apnea (OSA). Fifteen patients (12 males and 3 females) underwent polysomnographic recordings and lateral cephalograms before and after AMP use of at least 6 months. Measurements of sleep variables and upper airway morphology were compared between pre-AMP and with-AMP states. The AMP appliance reduced apnea-hypopnea indices (AHI) ~53% (33.77 ± 3.29 vs. 15.85 ± 3.78, P = 0.0013). Cephalograms of the oropharyngeal airway showed that the hyoid bone moved superiorly toward the inferior mandibular border (Δ H-MP) ~5 mm (23.4 ± 1.44 vs. 18.27 ± 1.86, P = 0.0377), with the AMP inserted in the oral cavity; no airway measurement other than hyoid bone position changed. No significant correlations emerged between AHI improvement (Δ AHI) and amounts of hyoid elevation (Δ H-MP) when all patients were pooled. However, when the samples were subcategorized, the correlation coefficients increased significantly (P < 0.01) in both subgroups. This outcome suggests the presence of two distinct types among the “Good-Responders” to AMP appliance use. Overall use of the AMP appliance is effective; however, the effectiveness of the appliance appears to depend on the mode of hyoid elevations, likely resulting from muscle responsiveness in patients with AMP use. The results suggest that Δ H-MP measurements may be a useful marker to segregate patients with tongue and hyoid muscles responsive to AMP from those not-so-responsive.
Highlights
Vertical positioning of the hyoid bone with respect to the inferior mandibular border obtained from lateral cephalograms appears to stratify obstructive sleep apnea (OSA) symptom severity provided that images are carefully collected under natural breathing-phase controlled conditions [1,2,3,4]
To understand the processes of anterior mandibular positioner (AMP) action, we propose that changes (Before– After) in hyoid bone position responding to AMP insertion would be a measure of responsiveness of the hyoid/tongue muscles, and could indicate effectiveness of the AMP
The initial analysis on 15 patients was completed with a pair of overnight sleep studies and cephalograms without (PreAMP) and with AMP (With-AMP) appliances
Summary
Vertical positioning of the hyoid bone with respect to the inferior mandibular border obtained from lateral cephalograms appears to stratify OSA symptom severity provided that images are carefully collected under natural breathing-phase controlled conditions [1,2,3,4]. Despite recent advances in three-dimensional imaging techniques, a simple measure of hyoid bone positioned low with respect to the mandible is one of the most practical measurements separating OSA patients from. Hyoid Bone and Oral Appliance asymptomatic controls [1, 5] This vertical measurement can be and consistently achieved by two-dimensional lateral head images as far as a natural head position at the end-expiration phase (end of exhalation) while the mandible is guaranteed to be in a resting position [6]. The superior displacement of hyoid bone position (or hyoid elevation) indicates a physiological responsive effort against pharyngeal narrowing by the pharyngeal dilating muscles
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
