Are oral appliances a substitute for nasal positive airway pressure?

lthough positive airway pressure (PAP) devices have become the mainstay of treatment for obstructive sleep apnoea, not all patients can or will use PAP on a nightly basis. Many patients find taking a bulky PAP unit on business or vacation trips a burden. In this issue of Thorax Smith and Stradling attempt to show that a simple non-adjustable oral appliance may be used in place of PAP on a short term basis. 1 Unfortunately, in only nine of the 50 patients entered into the study was their sleep apnoea controlled with the appliance. This low success rate of 18% does not concur with the published literature which has reported a success rate of 81% in patients with mild and 60% in patients with moderate sleep apnoea. 2 Part of the difference between this study and the previous literature may be related to the type of device used and side effects from the device. Smith and Stradling employed a device that had previously been shown to be effective in controlling snoring. 3 It consists of two customised sports-type mouth guards fused together to place the mandible in a forward position set at approximately 75% of maximum mandibular protrusion. The device covers both the teeth and the gums, so it differs from more commonly used devices such as the Herbst and the Klear-way which cover only the teeth and are adjustable, allowing gradual advancement of the mandible to a forward position at night to open the pharynx and prevent snoring and sleep apnoea. The difference in appliance configuration probably contributed to the low success rate. Thirty one of the subjects studied by Smith and Stradling gave up the device due to intolerable side effects such as sore gums, excessive salivation, and painful masseter muscles or temporo-mandibular joints. This contrasts markedly with other experiences with the appliance. We previously reported a study of 19 patients who had failed with nasal CPAP and changed to treatment with the Herbst mandibular advancement device. 4 At the time of the follow up sleep studies no patient reported pain or discomfort while wearing the removable Herbst appliance. Tegelberg and colleagues reported 45 patients randomised to treatment with an oral appliance adjusted to 50% of maximum mandibu-lar protrusion. 5 Only one patient withdrew from treatment for side effects— specifically, the patient developed recurrent aphthous ulcers related to an allergic reaction to the acrylic polymer. Fritsch et al randomised …