What is it?
In obstructive sleep apnoea, the muscles around the throat relax as you fall asleep and the airway narrows. While the narrowing is only enough to make a sound, you snore; when airflow stops completely or almost completely, breathing pauses for a short time. These pauses can repeat dozens of times, sometimes more, over the course of a night.
At the end of each pause the brain sends a brief waking signal; the muscles recover, the airway opens again and breathing usually returns with a noisy breath. Most of these awakenings are not remembered. Even when the hours of sleep look sufficient, the depth of that sleep is broken up, so you do not feel rested in the morning.
A dentist can see signs of this picture in the mouth: worn teeth, tooth marks along the side of the tongue, a narrow high palate, morning dryness and tenderness in the chewing muscles are common companions. These do not make the diagnosis, but they do put a sleep assessment on the agenda. Left unaddressed, high blood pressure, irregular heart rhythms and the road risk that comes with daytime sleepiness can all increase.
Signs
You will not necessarily have all of these at once.
Why does it happen?
- 01
Anatomy that narrows the airway
A lower jaw set further back, a narrow upper jaw, a large tongue base, a long soft palate and enlarged tonsils reduce the cross-section of the airway. When the muscles relax during sleep, this narrow section closes more easily.
- 02
Weight and neck size
As fatty tissue around the neck and the tongue increases, the airway is pressed on from the outside. Putting on weight can make the condition more severe; losing weight can ease the symptoms, although it may not be enough on its own.
- 03
Things that increase muscle relaxation
Alcohol, sedatives and muscle relaxant medicines lower the tone of the throat muscles. Tissue support decreases with age; in women the condition becomes more common after the menopause.
- 04
Not being able to breathe through your nose
Allergic blockage of the nose, a deviated septum and enlarged adenoids narrow the airway at its upper end. Once breathing shifts to the mouth, the lower jaw slides back and down, and the base of the tongue narrows the airway further.
How does it progress?
- Measurement
How severity is worked out
A sleep study gives the number of breathing pauses and shallow breaths per hour. That number is read together with the drops in oxygen and your daytime symptoms; a figure on its own does not decide the treatment.
- Mild
Between five and fifteen events an hour
Daytime symptoms may be limited. Sleeping position, weight management and treating a blocked nose are reasonable places to start; a mandibular advancement device is one of the options often considered in this group.
- Moderate
Between fifteen and thirty events an hour
Daytime sleepiness and high blood pressure are more marked in this group. The choice between the machine and a mandibular advancement device is made by a sleep specialist, looking at the findings as a whole.
- Severe
More than thirty events an hour
The drops in oxygen become deeper and sleep is clearly broken up. In this group the first option is usually CPAP; a mandibular advancement device may come up where the machine cannot be tolerated.
How is it treated?
The diagnosis is made with a sleep study. Respiratory polygraphy carried out at home, or polysomnography carried out in a sleep laboratory, records the breathing events and your oxygen level. Requesting the test and interpreting the result is the job of a respiratory physician, a neurologist or an ear, nose and throat doctor. A dentist does not begin treatment without the test result.
A CPAP machine, which delivers continuous positive airway pressure, holds the airway open from the inside and is considered first in moderate and severe cases. A mandibular advancement device works differently: it holds the lower jaw slightly forward to widen the space behind the base of the tongue. It is made for mild and moderate cases, and also where the machine cannot be tolerated, on the direction of a sleep specialist.
The dentist's role is to take the impressions, make the device, adjust the amount of advancement step by step and monitor the effects on the jaw joint and the teeth. Once you start using the device, its effectiveness is expected to be reassessed with a sleep study. Weight management, reviewing your use of alcohol and sedatives, treating a blocked nose and avoiding sleeping on your back are part of the process at every stage.
- Falling asleep at the wheel or while talking
- Waking at night choking or gasping for breath
- Waking from sleep with chest pain or an irregular, racing heartbeat
- Seeing your child stop breathing during sleep
How is it prevented?
- Avoid alcohol and sedative medicines in the hours close to bedtime; both relax the throat muscles.
- If your symptoms are worse when you sleep on your back, try sleeping on your side.
- Do not let a blocked nose drag on; ask for an ear, nose and throat assessment of allergic and structural causes.
- A change in weight can directly affect how severe the condition is; keep track of it together with your doctor.
Frequently asked questions
- I do not snore. Can I still have sleep apnoea?
- Yes, you can. Snoring is a common companion, but it is not essential. In people who sleep alone and in some women, the picture shows itself less through snoring and more through tiredness, morning headaches, poor concentration and frequent waking at night. The answer comes from a sleep study.
- Can a mandibular advancement device be made without a sleep study?
- No. A device fitted without knowing whether apnoea is present, and how severe it is, can reduce the sound of snoring while hiding the real problem. Whether the device suits you is also decided only by weighing up the test result together with the state of your teeth and gums and an examination of the jaw joint.
- Can I use a mandibular advancement device instead of CPAP?
- That decision belongs to your sleep specialist. In mild and moderate cases the device is considered as an option. In severe cases CPAP is generally kept in front; the device may come up where the machine cannot be tolerated. How well each method works varies from person to person.
This content is for general information and does not replace an in-person examination. Symptoms overlap between conditions, and a diagnosis can only be made clinically.