Obstructive Sleep Apnoea (OSA) is a sleep-related breathing disorder that is characterized by the repeated collapse of the upper airway during sleep, resulting in sleep deprivation. Mandibular Advancement Appliances (MAA) or Oral Appliances (OA) is prescribed for the patients with OSA and they have been shown to be effective. However, they rely entirely on the patient's acceptance and use. The aim of this study is to assess whether interventions- additional support approaches, will help patients use their MAA more as compared to those who receive routine care. The investigators also will try and identify factors that help us to understand why some patients choose to wear the MAA more than others. Adults (≥40 years) with a confirmed diagnosis of OSA (apnoea-hypopnoea index \>5) and referred for MAA therapy will be included in this study. It is a multicentre study comprised of recruiting patients from secondary care. Patients will be provided with information in relation to the study and written informed consent obtained at their subsequent appointment for placement of MAA. Patients will be randomly assigned to Intervention Care (IC) and Standardised care (SC). Patients will also be provided with a sleep diary to subjectively record their hours of sleep and usage of MAA and an objective adherence record from the micro-sensor included in their MAA design. Data indicating adherence will be collected and evaluated, both subjectively at 3- (T2) and 6-months (T3) and objectively by downloading the data stored within a micro-sensor placed in the MAA device. At the end of the follow-up, the investigators also plan to undertake a qualitative one-to-one interview with patients compliant (users) and non-compliant (non-users) to identify their views of what helps and/or prevents their adherence.