What it is
A custom oral appliance that holds the lower jaw forward
A mandibular advancement device, sometimes called an oral appliance or mandibular advancement splint, is a bespoke intraoral device that clips over the upper and lower teeth. It advances the lower jaw by 5 to 10 mm while asleep. Forward positioning of the mandible pulls the tongue base off the posterior pharyngeal wall, opens the retroglossal airway, and reduces upper-airway collapse during sleep.
NICE guideline NG202 (2021, updated 2023) recommends a custom mandibular advancement device as first-line therapy for mild to moderate obstructive sleep apnoea in adults, and as an alternative to CPAP for patients with moderate to severe OSA who cannot tolerate positive airway pressure.
Who it is for
The right candidates for a MAD
- Adults with mild to moderate OSA confirmed on sleep study (AHI 5 to 30).
- Primary snorers without OSA whose bed partner is disturbed.
- Positional-only OSA where events cluster in supine sleep.
- Patients with moderate to severe OSA who have declined, failed or removed CPAP.
- Frequent travellers for whom CPAP portability is a burden.
- Adequate dentition (typically at least eight healthy teeth per arch), stable periodontal health, and no active TMJ disorder.
Device options
Custom devices used in UK private sleep dentistry
SomnoDent Flex and Avant - acrylic bi-block design with lateral wings; widely used, comfortable and titratable in small increments.
Somnowell - cast cobalt-chromium, thin and durable, marketed as a low-profile long-life device; higher price point.
Herbst - metal telescopic bi-block with a long clinical track record; robust for bruxism.
Narval CC (ResMed) - CAD/CAM nylon, lightweight and flexible, well tolerated in patients who reject bulkier acrylic designs.
Over-the-counter boil-and-bite devices sold online are not recommended. They deliver inconsistent advancement, unpredictable retention and a higher rate of TMJ complaints and dental drift.
The pathway
From impressions to titrated device
- Consultation and dental screening: sleep history, examination of teeth, periodontium and TMJ, review of the diagnostic sleep study.
- Impressions or intraoral 3D scan of upper and lower arches.
- Protrusive bite registration at 60 to 70 per cent of maximum mandibular advancement.
- Two to four weeks in the specialist laboratory for fabrication.
- Fitting appointment: insertion, adjustment for comfort, home instructions.
- Self-titration at home in 0.25 mm increments over four to eight weeks until snoring and sleep quality plateau.
- Repeat home sleep study at six to twelve weeks to confirm residual AHI is below 10.
How well it works
Efficacy
In mild to moderate OSA, a well-titrated custom device reduces AHI by 50 to 70 per cent, with roughly half of patients achieving a residual AHI below 5 and around two-thirds below 10. Snoring is subjectively eliminated or greatly reduced in over 80 per cent of users. CPAP remains more effective than a MAD for AHI reduction, particularly in severe disease, but real-world clinical benefit is often comparable in mild to moderate OSA because nightly adherence to an oral appliance is higher.
Side effects
What to expect
- Dry mouth or excessive salivation in the first weeks.
- Morning jaw stiffness for two to three weeks, resolving with prescribed exercises.
- Persistent TMJ discomfort in 10 to 15 per cent of users.
- Gradual bite change (posterior open bite, retroclined incisors) in 15 to 25 per cent of long-term users over several years.
- Tooth movement, gum irritation and loosening of existing dental work in a minority of cases.
Cost in London
Typical private fees
Custom acrylic bi-block devices (SomnoDent, Herbst): £550 to £1,400, usually including consultation, impressions, fitting and one review.
CAD/CAM nylon devices (Narval CC): £1,200 to £1,800.
Cast cobalt-chromium (Somnowell): £1,500 to £2,200.
A repeat home sleep study to confirm efficacy is typically £200 to £350 and is often not included in the appliance quote.
Where it is offered
Recognised London sleep dentistry services
- Royal Brompton Hospital Sleep and Ventilation Service.
- London Sleep Centre, Harley Street.
- HCA The Wellington Hospital, dental sleep service.
- Cromwell Hospital (Bupa Cromwell), sleep and respiratory.
- London Sleep and Snoring Centre.
Related
Related pathways
- CPAP titration and fitting clinicPositive airway pressure setup for moderate to severe OSA.
- Inspire hypoglossal nerve stimulatorImplanted therapy for CPAP-intolerant moderate to severe OSA.
- Positional therapy for OSASupine-avoidance devices for positional-only sleep apnoea.
- Sleep studyHome polygraphy and in-lab polysomnography.
- Sleep apnoeaCondition guide with causes, symptoms and treatment options.