A randomized clinical trial of the treatment of obstructive sleep apnoea using oral appliances

Abstract

 Obstructive sleep apnoea (OSA) is the most common sleep-related breathing disorder and is associated with a range of adverse physical, social and psychological outcomes that affect quality of life (QoL). Two systematic reviews of the literature (part of this thesis work) found there is conflicting evidence of how different mandibular advancement device (MAD) designs features may affect clinical and subjective OSA outcomes in certain patients. Therefore, a randomized cross-over trial was conducted. Firstly, the correlation between clinical OSA indicators and QOL was explored among patients referred for OSA treatment using MADs. In addition, associations of OSA risk factors, dental status and demographic variables with clinical OSA indicators and QoL indices were determined. Secondly, the efficacy of two different MADs in the treatment of adult OSA patients was assessed and compared. Thirdly, the efficacy of the two MADs in the treatment of adult OSA patients from the subjective perspective of their bed partners was determined.

A consecutive sample of 45 adult OSA patients referred from Queen Mary Hospital Sleep Centre to the Prince Philip Dental Hospital for oral appliance therapy was recruited and treated with a monobloc MAD and a twinblock MADs for a period of 3 months per MAD (cross-over randomised trial). Changes in clinical OSA outcomes were assessed by polysomnography (PSG) and changes in subjective outcomes by the disease-specific Sleep Apnoea Quality of Life Index (SAQLI) questionnaire, the Functional Outcome of Sleep Questionnaire (FOSQ) and Epworth Sleepiness Scale (ESS). Patient compliance, side-effects and MAD preference, as well as MAD treatment impact on the patients’ bed partner was also assessed.

At baseline, some clinical OSA indicators, subjective QoL and certain OSA risk factors were significantly correlated (p<0.05). There were significant variations in clinical OSA indicators and subjective QoL indices with respect to certain risk factors (p<0.05), demographic variables (p<0.05) and dental status (p<0.01).

There was a significant difference in favour of the monobloc MAD in terms of improving the apnoea-hypopnoea index (AHI) (p<0.05) and oxygen desaturation index (ODI) (p<0.01). Significantly more patients achieved clinical treatment success with the monobloc compared to the twinblock (p<0.05). Both MADs were efficacious in improving patients’ SAQLI score (p<0.01), FOSQ score (p<0.01) and ESS score (p<0.01). Significantly more patients achieved QoL treatment success with the monobloc (p<0.05) compared to the twinblock. More patients were ‘very satisfied’ with the monobloc treatment (p<0.05) and 63% preferred it to the twinblock.

No significant difference was found between patients’ and bed partners perceptions of symptom improvement post treatment, however, the monobloc resulted in a significant reduction in bed partners’ daytime sleepiness (p<0.01) and allowed significantly more co-sleeping at night (p<0.05).

This study concluded that the monobloc is superior in improving subjective QoL and clinical OSA indicators. The monobloc was the preferred MAD and patients were more satisfied with it; bed partners rated this MAD as superior in improving their own daytime sleepiness and co-sleeping.