How to fit a boil-and-bite snoring mouthpiece

What’s going on

A boil-and-bite mouthpiece has a soft lining that melts a little in hot water. You bite into it while it’s warm, and it sets in the shape of your teeth. It then holds your lower jaw slightly forward, which can reduce snoring. Jaw-advancing mouthpieces as a group Strong have strong evidence, but evidence for store-bought ones on their own is thinner.

The fit decides how well it works and how your teeth feel in the morning. A loose one falls out or does nothing. A badly molded one can make your teeth and jaw sore.

Before you start, check that a mouthpiece is right for you. Skip it if you’re under 18, might have sleep apnea, or have loose teeth, gum disease, dentures, braces or jaw joint problems. See who shouldn’t use a snoring mouthpiece.

A fitting video is coming. Until then, the steps below are general. Your mouthpiece’s own instructions come first, because times and temperatures differ between brands.

How to fit it, step by step

1. Read the whole booklet first. Note the soaking time, how to heat the water, and how many times you can refit. Some makers allow only one or two tries.
2. Set it to the starting position. Adjustable mouthpieces come at a factory setting. Leave it there for fitting unless the booklet says otherwise.
3. Brush your teeth. Clean teeth leave clearer marks.
4. Heat the water the way the maker says. One maker warns against a stove-top pan, because hot metal can damage the material.
5. Soak it for the time given, no longer. Use a timer. Lift it out with the handle or a spoon, not your fingers.
6. Dip it in cool water for a second or two. That takes the scalding surface heat off.
7. Center it and bite. Line the middle of the trays up with your front teeth, top tray on top. Bite into the soft lining for the time the booklet gives.
8. Let it set in cool water. Leave it for the full time listed before you handle it or try it on.
9. Check the marks. You should see clear prints of each tooth in both trays.

Common mistakes

• Biting too hard. Your teeth can push right through the soft lining to the hard tray. That leaves thin spots and a poor grip. Bite until your teeth are well seated, then hold.
• Water too hot, or soaking too long. The lining can get too soft and lose its shape. Heat also warps plastic, which is why Cleveland Clinic warns against hot water for mouth guards in general.
• Too far forward on day one. The expert panel of dental sleep specialists recommends moving the jaw forward conservatively. They note side effects rise as the jaw is pushed past half of its forward reach.
• Off center. If the mouthpiece sits to one side, your jaw will too. Look in a mirror while you bite.
• Skipping the setting time. Handling it warm can smear the tooth marks.

How to tell the fit is right

• It stays in when you open your mouth slightly, without you biting to hold it.
• Your teeth sit fully in their marks, with no rocking.
• Nothing presses hard on one tooth or digs into your gums.
• Your jaw feels gently held forward, not strained.

Some tenderness in the teeth, jaw or gums in the first days is common. So is extra saliva, which the expert panel says usually eases with time. One maker suggests wearing it for one to three hours while awake on the first two or three days, to get used to it.

Adjusting after the fit

If you still snore after a few nights, move the jaw forward by one small step. Then wait several nights before the next step. Stop at the setting where the snoring eases and your jaw feels fine.

A bite that feels different on waking is a known side effect. The expert panel’s first steps are waiting it out, jaw stretches, and a morning bite guide from a dentist. If the change lasts through the day, go back a step and talk to a dentist.

When to refit or replace it

Refit, if your mouthpiece allows it, when:

• The marks are faint or a tooth doesn’t sit in them.
• It slips out at night.
• You’ve had a filling, crown or other dental work that changed a tooth’s shape.

Replace it when the lining tears, the tray cracks, or it no longer holds. Cleveland Clinic says store-bought guards may need replacing a few times a year. If it never fits well after the allowed tries, don’t keep forcing it.

How to clean it

• Rinse it in cool water after each use.
• Clean it with a soft brush and mild soap, or as the booklet says.
• Skip bleach, alcohol mouthwash and hot water.
• Let it air dry, then keep it in a vented case away from heat and sunlight.

What a dentist or doctor can do

A dentist can check the fit, look for bite changes, and watch your teeth and gums over time. Tell your dentist you wear one at your next checkup. FDA guidance lists tooth movement, bite changes and jaw joint soreness among the possible effects.

If you snore loudly, someone has seen you stop breathing, or you’re sleepy all day, see a physician. A physician diagnoses sleep apnea; a snoring mouthpiece doesn’t treat it.