Dose-dependent effects of mandibular advancement on pharyngeal mechanics and nocturnal oxygenation in patients with sleep-disordered breathing

Study objectives: To examine dose-dependent effects of mandibular advanceme nt on collapsibility of the passive pharynx and sleep-disordered breathing (SDB), Design: Prospective, randomized study. Setting: University hospital. Patients: Thirty-seven adult patients with SDB, Interventions: Oral appliances with 2-, 4-, and 6-mm advancement of the man dible, Measurements and results: Overnight oximetry was performed with and without oral appliances, Each 2-mm mandibular advancement coincided with approxima tely 20% improvement in number and severity of nocturnal desaturations. Per centages of patients producing a > 50% improvement rate of the number of de saturations were 25%, 48%, and 65% with use of oral appliances with 2-, 4-, and Ci-mm mandibular advancement, respectively. Static pharyngeal mechanic s mere evaluated in six completely paralyzed patients with SDB under genera l anesthesia with and without the oral appliances, Advancement of mandibula r position,vas found to produce dose-dependent closing pressure reduction o f all pharyngeal segments, Normalization of nocturnal oxygenation was assoc iated with negative closing pressure, especially at the velopharynx. Conclusions: We: conclude that improvement of both nocturnal oxygenation an d pharyngeal collapsibility significantly depends on the mandibular positio n.