A prospective evaluation assessing the effectiveness of the 'Dynamax' mandibular appliance in the management of obstructive sleep apnoea.

BACKGROUND: Obstructive sleep apnoea syndrome (OSAS) affects 4-6% of the middle-aged UK population and is responsible for significant partnership disharmony. Nasal CPAP therapy is effective but has poor compliance in less severe cases- bulky with poor portability and frequently deemed socially unacceptable. The 'Dynamax mandibular appliance (DMA) is a current treatment for Skeletal 11 malocclusion characterised by mandibular retrusion. It has the advantage of both maxillary expansion and mandibular advancement and is developed and tailored on an individual basis by orthodontic sculpture. These facilities are widely available in hospital-based orthodontic departments. For these reasons we have explored its use in the treatment of mild to moderate cases of OSAS.

METHOD AND MATERIAL: 35 symptomatic patients (29 males) with mild to moderate OSAS, determined from sleep study analysis, had dental impressions taken and the 'Dynamax' appliance constructed. Following fitting and instructions for use, all patients were entered into the study. After two months, repeat overnight oximetry was undertaken for 16 patients and both an Epworth sleep score (ESS) and quality of life questionnaire completed.

RESULTS: The mean age was 51 (range 29-71) years. The mean ESS pre-treatment was 12 (range 7-19) with a significant fall post-treatment by 7 (range 3-14) (p < 0.0001). Pre-treatment oximetry data confirmed typical tracings and patterns of OSAS with a mean low oxygen saturation (SaO2) of 83% (range 71-90%). Post-treatment oximetry was available in 16 patients and showed significant improvement in the number of hourly SaO2 desaturation dips and a mean increase of 4.7% in the lowest SaO2 recorded (p < 0.0001). Thirty (86%) patients found the appliance of 'great to moderate' benefit and 18 (60%) were able to tolerate it and be fully compliant within days. Of 10 patients who had previously experienced CPAP, 80% of them felt it was easier to tolerate the DA. Sixty-seven percent of these patients stated the appliance was more portable and acceptable to their bed partner. Twenty-one (70%) of bed partners reported softer and less frequent snoring. Ninety percent of the patients in this study wished to wear the DMA long-term.

CONCLUSION: The DMA provides a satisfactory alternative therapy in the treatment of OSAS of'mild-moderate' severity. This oral device is conveniently small, readily portable and well tolerated by both patients and bed partners alike. It can be fashioned in orthodontic departments available in all district general hospitals and will enhance the provision and development of any local sleep service.