Mandibular advancement appliances for treating sleep apnoea/hypopnoea syndrome

Abstract

Randomised controlled crossover trial. Sixteen participants (13 men and three women) with mild to moderate OSAHS, diagnosed using polysomnography (PSG), were recruited from a sleep clinic. To be included, participants had to have 20 or more teeth (sufficient to provide retention for oral appliances), have had no previous OSAHS treatment, been unable to tolerate nasal continuous positive airway pressure and be free from caries, periodontal disease, temporomandibular joint (TMJ) pain or movement limitations. One-night mandibular advancement titration was carried out using a custom made temporary dental appliance to reach each individual's pre-determined maximum voluntary advancement value. Participants were given one week to acclimatise. Two different MAAs were made to this titrated value for each participant; the SILENT NITE (a two-piece MAA in flexible trays connected by two plastic bars to maintain mandibular advancement) and a one-piece resin-made activator appliance which was retained by posterior tooth clasps. Patients were 'randomly divided' into two groups and wore one or other appliance as allocated for three months. Following a two week washout period, they then wore the other appliance for a further three months. Subjective measures were recorded pre- and post treatment using Epworth's Sleepiness Scale and an unspecified Snoring Scale. Preferences, compliance and side effects were assessed through interviews with patients and their families. Pre- and post treatment objective measures were taken using a variety of PSG results which were manually scored by a blinded operator (these included EOG, ECG, supplemental EMG, nasal-oral airflow, abdominal and chest respiratory effort, ECG rhythm). Cephalometric radiographs taken pre- and post treatment were scored by a single examiner for upper airway space diameters. Baseline measures for both BMI and titrated distances for mandibular advancement were similar for both groups. Daytime performance (ESS) and snoring (SS) showed significant improvement for both MAAs during treatment but there were no significant differences between the appliances. Out of the 16 participants, seven preferred the monoblock appliance, two preferred the two-piece and seven had no preference. All patients finished treatment and stated full compliance despite some of the participants experiencing side effects; two had ulcers for several weeks at the start of treatment, four experienced TMJ pain, three complained of muscle discomfort and four felt some dental discomfort. PSG showed that total sleep time did not differ pre- and post treatment and sleep efficiency increased for the monoblock appliance only. Both appliances showed improvement in AHI, AI and Hypopnoea Index, but the monoblock had a more statistically important improvement for AHI and AI. Upper airway space diameters were increased with both MAAs but there were no significant differences between the appliances. Both the monoblock and the SILENT NITE appliances were effective at reducing the severity of symptoms of OSAHS. The monoblock, however, offered some advantages over the two-piece appliance in achieving a greater improvement in Apnoea Hypopnoea Index and Apnoea Index and being preferred by most patients.