Mouth ulcers from dentures and braces: why they happen and what helps

Badly fitting dentures, braces and other dental appliances are among the most common causes of mouth ulcers. The UK's National Health Service (NHS) lists them, with sharp teeth and rough fillings, as everyday triggers that can often be avoided.

Because this kind of ulcer usually has a clear cause, it tends to heal on its own once that cause is dealt with.

Why dentures and braces cause ulcers

The lining of the mouth is soft and thin. When something hard rubs the same spot again and again, the surface wears through and an ulcer forms. Dentists call this a traumatic ulcer, meaning it comes from an injury rather than an infection.

The usual culprits are:

• New dentures that have not yet settled, or older dentures that no longer fit because the gums have changed shape.
• A denture with a rough or sharp edge, or one that rocks when you chew.
• Braces, whose brackets and wires can rub the inside of the lips and cheeks, especially in the first weeks and after each adjustment.
• A loose wire, or one that has poked out at the back.
• Retainers and mouthguards that press on one area.

The Oral Health Foundation adds that an injury usually causes a single ulcer rather than several at once.

Looking after your mouth with dentures

If you wear dentures, the NHS advises:

• Allow a few weeks to get used to new dentures. Softer foods help in the meantime.
• Clean your dentures morning and evening, and rinse them after eating.
• Brush your gums, tongue and any natural teeth twice a day.
• Take your dentures out at night so your gums can rest, unless your dentist advises otherwise.
• Do not try to adjust or file a denture yourself.

Looking after your mouth with braces

If a bracket or the end of a wire is rubbing, ask your orthodontist about orthodontic wax. A small piece pressed over the spot can stop it rubbing the cheek while the area heals. Brush gently with a soft toothbrush, and keep the area around the brackets clean.

Expect some soreness for a few days after each adjustment. Never cut or bend a wire yourself. If one comes loose or sticks out, call your orthodontist.

Easing the discomfort while an ulcer heals

Whatever the cause, the NHS suggests a few simple steps:

• Eat softer foods, and avoid food that is very spicy, salty, acidic or crunchy.
• Choose cool drinks, through a straw if that helps, and avoid very hot ones.
• Use a soft toothbrush. If your toothpaste seems to irritate the ulcer, try one without sodium lauryl sulphate.
• Ask a pharmacist about a suitable product for the pain.

When to see a doctor or dentist

Go back to your dentist or orthodontist if a denture or brace keeps rubbing or causing pain, or if it feels loose, clicks or rocks. The appliance usually needs adjusting, and the ulcer will keep coming back until that is done.

See a doctor or dentist if an ulcer:

• lasts more than 3 weeks;
• keeps coming back in the same place;
• is larger than usual, or looks different from ulcers you have had before;
• bleeds, or becomes more painful and red;
• comes with a fever, or with feeling generally unwell.