A Clinical Study Evaluating a Mandibular Repositioning Appliance to Treat Obstructive Sleep Apnea

Abstract

The study evaluated the effects of a mandibular repositioning appliance (MRA) in patients with obstructive sleep apnea. The MRA was designed to hold the mandible anteriorly in an attempt to maintain a patent airway. Eleven subjects completed a full-night polysomnogram wherein their normal sleep was recorded half the night without the appliance (control) and the other half with the appliance (test). The sequencing of test and control halves was randomly assigned to avoid bias. After seven subjects were tested with the MRA, the MRA was modified for four additional patients by placing anterior vertical elastics (MRA*) to minimize the opening of the mandible. The skeletal and soft tissue changes with both appliances were analyzed using lateral cephalometric radiographs.

The MRA was found to have no significant effect on the obstructive sleep apnea patients as a group. Individual response to the appliance varied from noticeably worse to marked improvement. Subject #2A exhibited the reduction of a moderate-to-severe apnea (Apnea-hypopnea index 55.92) to a clinically acceptable level (Apnea-hypopnea index 9.57) with appliance wear. The treatment was considered successful. Significant cephalometric changes with appliance wear were increased lower facial height, a superiorly positioned hyoid bone relative to the mandibular plane, and a decreased posterior airway space. No cephalometric measurement could accurately predict the outcome of the treatment, and posterior airway space, commonly measured in sleep research, was not reliable.

The mandibular repositioning appliance was effective in treating a small percentage of individuals with obstructive sleep apnea. A polysomnogram was needed to quantitatively measure the effectiveness of treatment. Under no circumstance should a subjective evaluation by the patient or the clinician be used to assess treatment results. Further investigation is required to evaluate the long-term effectiveness of this treatment. Periodic follow-up sleep studies are required for any patient treated with this appliance until more long term studies are completed.