Mandibular advancement devices are the most widely used dental treatment for obstructive sleep apnoea (OSA) and snoring. They are recommended in current clinical guidelines as a first-line treatment option for mild-to-moderate OSA, particularly for patients who are unable to tolerate continuous positive airway pressure (CPAP) therapy. For dental professionals working in sleep medicine, a thorough understanding of how mandibular advancement devices work and the different types available is foundational to effective clinical practice.
At the British Academy of Dental Sleep Medicine (BADSM), training in oral appliance therapy is central to our curriculum. This article provides an overview of MADs, how they function, the main types available, and their role in treating sleep disordered breathing in the UK.
What Are Mandibular Advancement Devices?
Mandibular advancement devices are oral appliances worn during sleep that hold the lower jaw (mandible) in a slightly forward and downward position. By advancing the mandible, MADs increase the space in the upper airway, reduce the tendency of soft tissues to collapse during sleep, and help maintain airway patency throughout the night.
They are used primarily to treat:
- Obstructive sleep apnoea (mild to moderate)
- Primary snoring
- Upper airway resistance syndrome
How Do Mandibular Advancement Devices Work?
The mechanism of mandibular advancement devices is biomechanical. When the mandible is held in a forward position during sleep, several physiological changes occur in the upper airway:
- The tongue and associated soft tissues are displaced anteriorly, increasing retroglossal space
- The pharyngeal walls are stretched and tensioned, reducing their propensity to collapse
- Hyoid bone position is altered, further contributing to airway patency
- The soft palate is repositioned, reducing soft tissue vibration that causes snoring
The degree of mandibular advancement required varies between patients. Most titratable devices allow clinicians to adjust the amount of protrusion incrementally, finding the minimum effective advancement that reduces symptoms while minimising side effects.
Types of Mandibular Advancement Devices
Understanding the different types of mandibular advancement devices is essential for matching the right device to each patient.
Custom-Made (Laboratory-Fabricated) MADs
Custom-made MADs are fabricated from dental impressions or digital scans by a dental laboratory. They are precision-fitted to the individual patient’s dentition, providing superior comfort, retention, and clinical control compared to over-the-counter alternatives.
Custom devices are the standard of care for treating OSA in a dental sleep medicine setting. They allow for accurate titration, are durable, and are associated with higher long-term adherence. In clinical practice in the UK, custom-made MADs are the device type recommended for patients receiving formal treatment within a sleep medicine pathway.
Thermoplastic (Boil-and-Bite) Devices
Thermoplastic devices are available without a dental prescription and are self-fitted using a heat-and-mould process. While accessible and low-cost, they are not recommended as a primary clinical treatment for OSA because they cannot be accurately titrated, offer limited control over the degree of advancement, and typically have shorter lifespans and lower adherence rates than custom devices.
Their role in clinical practice is limited. Some practitioners use them as interim devices while a custom appliance is being fabricated, but they should not be presented to patients as equivalent to laboratory-made MADs.
Titratable vs Non-Titratable MADs
Within the category of custom-made devices, a key distinction exists between titratable and non-titratable designs.
Titratable MADs allow incremental adjustment of the degree of mandibular advancement after fitting. This enables clinicians to work with patients over several weeks to find the optimal therapeutic position, balancing symptom reduction with patient comfort. Examples include devices with built-in screw mechanisms or interchangeable connector systems.
Non-titratable MADs are fabricated to a fixed advancement position. They are simpler in construction and typically less expensive, but do not allow for adjustment if the initial position proves suboptimal or if the patient’s clinical needs change over time.
For most patients receiving treatment for OSA, titratable devices are preferred because they allow a more personalised and responsive approach to care.
MADs vs CPAP: Comparing the Options
CPAP delivers a constant stream of pressurised air through a mask to keep the airway open during sleep. It is highly effective for all severities of OSA and remains the first-line recommendation for severe OSA.
However, CPAP adherence is a well-documented challenge. Intolerance of the mask, noise, and inconvenience leads a significant proportion of patients to abandon the therapy. For these patients, and for those with mild-to-moderate OSA, mandibular advancement devices offer a clinically effective and better-tolerated alternative.
Guidelines from the British Thoracic Society and NICE recognise MADs as a recommended treatment option for mild-to-moderate OSA and for patients who prefer oral appliance therapy or who cannot tolerate CPAP.
Who Is Suitable for MAD Therapy?
Not all patients are appropriate candidates for mandibular advancement devices. Assessment requires consideration of dental, periodontal, and temporomandibular joint (TMJ) status. Patients with severe periodontal disease, insufficient dentition, or significant TMJ dysfunction may not be suitable.
Key candidacy considerations include:
- Presence of adequate dentition to support and retain the device
- Absence of active periodontal disease
- No significant TMJ pathology or pain
- Adequate range of mandibular movement
- Diagnosis of mild-to-moderate OSA (or primary snoring), ideally confirmed by a sleep study
Dentists trained in dental sleep medicine are equipped to carry out this assessment and to manage patients appropriately, including co-management with sleep physicians where needed.
Mandibular Advancement Devices in the UK
The use of mandibular advancement devices in the UK has grown considerably following updates to NICE guidance that formalised oral appliance therapy as a recommended treatment for OSA. NHS and private providers are increasingly offering MAD therapy as part of their sleep medicine services.
For dental professionals interested in providing MAD therapy, formal training is essential. BADSM offers comprehensive courses in dental sleep medicine, covering device selection, patient assessment, fitting, titration protocols, and long-term management.
Frequently Asked Questions
Are mandibular advancement devices effective for obstructive sleep apnoea?
MADs are well supported by clinical evidence for mild-to-moderate OSA and primary snoring. They reduce the apnoea-hypopnoea index (AHI), improve oxygen saturation, and improve sleep quality and daytime functioning. Outcomes are generally strongest in patients with mild-to-moderate OSA and in those with positional OSA.
How long does a mandibular advancement device last?
Custom-made MADs typically last three to five years, depending on the device type and the patient’s level of parafunctional activity such as bruxism. Regular clinical review allows for monitoring of device condition, dental changes, and ongoing therapeutic effectiveness.
What are the common side effects of MADs?
The most commonly reported side effects include temporary tooth soreness, jaw muscle discomfort, and increased salivation, particularly during the initial adjustment period. Excessive advancement can lead to TMJ discomfort. These effects are usually manageable through titration adjustments and typically reduce over time. Long-term dental changes, including minor bite changes, have been reported with prolonged use and should be monitored as part of regular review.
Can any dentist fit a mandibular advancement device?
Technically, any registered dentist can fit a MAD, but doing so safely and effectively within a sleep medicine framework requires specialist training. Dentists providing MAD therapy for OSA should be able to carry out appropriate patient assessment, interpret sleep study results, titrate devices effectively, and coordinate with sleep medicine colleagues. BADSM training equips dental professionals with all of these competencies.
