CPAP is the best-studied treatment for obstructive sleep apnoea, and for severe cases with high AHI counts it remains the standard. But compliance rates are sobering. Studies consistently show that 30 to 50 percent of people given a CPAP machine stop using it within a year, and the most common reason is simple: they cannot sleep with a mask strapped to their face.
That is where a dental splint enters the conversation, and it is a conversation worth having because the alternative to effective treatment is not trivial. Untreated moderate obstructive sleep apnoea is associated with increased cardiovascular risk, poorer metabolic control in diabetics, and a substantially higher crash risk when driving.
What obstructive sleep apnoea actually is
The obstructive variety, which accounts for the vast majority of cases, happens when the soft tissues of the throat collapse inward during sleep and block the airway. The diaphragm keeps trying to breathe, the body registers the obstruction, oxygen drops, and the brain wakes you just enough to restore muscle tone and reopen the airway. Most people have no memory of these arousals, even when they happen dozens of times an hour.
The symptoms that reach the dentist are usually the snoring (which is the partial obstruction), the partner who has moved to the spare room, the morning headaches, the jaw clenching that comes with it, and the person who has already seen a sleep physician and been told they need CPAP but never managed to use it.
How a mandibular advancement splint works
The dental splint operates on a mechanical principle. The lower jaw sits a few millimetres forward of its habitual position. When the jaw is held forward, the tongue base and the soft palate move forward with it, which increases the posterior airway space and reduces the degree to which the tissues can collapse inward during sleep.
The effect is not quite as large as CPAP, which holds the airway open with positive pressure regardless of jaw position. But for mild to moderate obstructive sleep apnoea, randomised controlled trials have found mandibular advancement splints comparable to CPAP for symptom reduction, with substantially better compliance because people actually wear them.
At Whitehorse Dental, we fit two types.
Dorsal appliances have separate upper and lower components connected by a fin-and-slot mechanism. The lower component can be advanced in small increments after fitting, which allows the protrusion to be titrated over the first few weeks. Most people start at around 50 to 60 percent of their maximum protrusion and work forward until symptoms reduce.
Nylon mandibular advancement splints are a firmer, single-piece design. They are more durable and generally suit people with moderate to severe clenching, where the dorsal appliance would wear too quickly.
The assessment before fitting
We screen for obstructive sleep apnoea at comprehensive examinations as part of the routine assessment, which includes jaw joints, bite, and any wear patterns on the teeth. Bruxism and sleep apnoea coexist frequently, and the grinding is sometimes the first visible sign that the airway is under stress during sleep.
Before fitting a splint, we need one thing: a confirmed diagnosis. That means a sleep study, either a home-based device study (simpler, usually done via a GP referral) or a full overnight polysomnography. We do not fit a splint on the basis of snoring alone, because snoring without apnoea is a different problem and would not justify moving your jaw forward every night for years. The sleep study is also what determines severity, and it is what we send back with the patient to their GP or sleep physician so the treatment is part of a coordinated record.
Assuming a diagnosis comes back and the case is appropriate for dental management, we take records, scan with the Medit intraoral scanner to make the working models, and the splint goes to a dental laboratory. The second appointment is the fit and handover, and then we follow up after a few weeks to adjust the protrusion.
We do not use this appliance where: the patient has severe sleep apnoea (AHI above 30, or where oxygen desaturation is substantial), where the patient has significant temporomandibular joint symptoms that protrusion might worsen, or where there are insufficient teeth to support the appliance. These are all things we assess at the first appointment. Where a splint is not appropriate, we refer back to the sleep physician for CPAP or another pathway, and we say so plainly.
Snoring without apnoea
Snoring that is not associated with apnoea, no oxygen desaturation and no apnoeic events on the sleep study, is not a medical condition in the same sense. But it disrupts sleep for partners and sometimes for the snorer. A mandibular advancement splint will reduce or eliminate snoring in most cases where the cause is posterior tongue base collapse. We are transparent that the medical indication here is quality-of-life rather than disease management, and we discuss it on those terms.
The jaw side effects, and how we manage them
Advancing the mandible is not free. The most common side effects are morning tooth soreness and joint stiffness, which typically settle within an hour. Some people have transient occlusal changes: the bite feels different first thing, and for a small number of patients this is permanent. This is the reason we do not fit these appliances without a proper baseline record of the bite, and it is the reason we build in the adjustment appointments rather than posting the splint and hoping.
The compliance benefit over CPAP is clear: most people wearing a mandibular advancement splint keep wearing it, including people who failed CPAP. But it does require looking after. It needs cleaning each morning (not in the dishwasher; a toothbrush, cool water and a mild soap). It needs a review appointment at six to twelve months where we check the position and the bite. And the sleep study should be repeated after treatment to verify the AHI has reduced, which is the standard recommended by sleep medicine guidelines and is not always done but should be.
Where to start
If you snore, wake unrefreshed, or have already been told you have sleep apnoea but could not manage CPAP, it is worth a conversation. We assess this at a comprehensive examination where jaw joints, wear patterns and bite all get looked at together. The snoring and sleep apnoea service page sets out the full pathway.
We are at 129A Canterbury Road, Blackburn, with on-site parking and Saturday mornings available. Call (03) 8838 8820 or text 0435 025 318.
Related reading: why teeth break and chip covers how sleep bruxism shows up on teeth, and TMJ jaw pain is the service page for the joint symptoms that can accompany apnoea. If a custom mouthguard is the other appliance you are considering, how a mouthguard should fit explains what a well-fitted oral device should feel like.