Study objectives: To examine dose-dependent effects of
mandibular advancement on collapsibility of the passive pharynx and
sleep-disordered breathing (SDB).
Setting: University hospital.
Patients: Thirty-seven adult patients with SDB.
Interventions: Oral appliances with 2-, 4-, and 6-mm
advancement of the mandible.
Measurements and results:
Overnight oximetry was performed with and without oral appliances. Each
2-mm mandibular advancement coincided with approximately 20%
improvement in number and severity of nocturnal desaturations.
Percentages of patients producing a > 50% improvement rate of the
number of desaturations were 25%, 48%, and 65% with use of oral
appliances with 2-, 4-, and 6-mm mandibular advancement, respectively.
Static pharyngeal mechanics were evaluated in six completely paralyzed
patients with SDB under general anesthesia with and without the oral
appliances. Advancement of mandibular position was found to produce
dose-dependent closing pressure reduction of all pharyngeal segments.
Normalization of nocturnal oxygenation was associated with negative
closing pressure, especially at the velopharynx.
Conclusions: We conclude that improvement of both
nocturnal oxygenation and pharyngeal collapsibility significantly
depends on the mandibular position.