Twenty-one studies (n=304) were included: 2 case reports and 19 case series.
Improvement in 73 to 100% of patients was reported in all 9 studies; these were based mainly on subjective self-reporting by patients and their bed partners.
All reports showed an improvement in the average AHI when using an appliance. Of the 271 cases with data reported in a form suitable for calculation, the mean AHIs before and with treatment were 42.6 and 18.8, respectively, an average reduction of 56%. The degree of improvement varied. Although 70% of the patients in these studies showed at least a 51% reduction in AHI, many did not return to normal levels, whilst some patients showed no improvement or became worse. Fifty per cent of patients achieved normal breathing (defined as an AHI of less than 10 with treatment), and 39% of patients with an initial AHI of greater than 20 remained above that level with treatment. In the 14 studies presenting data for individual patients, 20 patients (13%) had a greater AHI with treatment than before.
Sleep and sleepiness.
Polygraphic assessments of sleep before and during oral appliance treatment have shown a reduction in stage I sleep, an increase in slow wave and stage REM (rapid eye movement) sleep, and a reduction in sleep fragmentation, mid-sleep wake time and arousal.
Excessive salivation and transient discomfort, for a brief time after awakening, are commonly reported with initial use and may prevent early acceptance of oral appliances. Later complications may include temporomandibular joint (TMJ) discomfort and changes in occlusive alignment. Published reports suggest that TMJ pain and occlusal changes are relatively uncommon occurrences but the long-term risk of these complications is not well-defined. Compliance data are limited, but reports have ranged from 50 to 100%.