Broken Tooth Edge Cutting Your Tongue? Immediate Relief and Next Steps

It starts as a mild novelty — something has changed on one of your teeth and your tongue keeps checking it. Within a day the checking has become compulsive and the side of your tongue is raw.

This is one of the more disproportionately miserable dental problems. The chip itself might be tiny. The soreness it produces can make eating, speaking and sleeping genuinely unpleasant.

There is a straightforward way to interrupt it, and it takes about a minute.

What gives immediate relief?

Cover the edge. Dry the tooth with a tissue, then press a small piece of orthodontic or dental wax firmly over the sharp area — sugar-free chewing gum works if you have no wax. This stops the abrasion immediately and allows the ulcer to begin healing. Rinse with warm salt water several times a day, take suitable over-the-counter pain relief if needed, and avoid acidic or spicy food while the tissue is sore. Then contact your practice, since smoothing a sharp edge is usually a very short appointment and the underlying cause needs identifying.

Biting something hard — ice, a boiled sweet, an olive stone, a popcorn kernel — or a knock to the face. Enamel is the hardest tissue in the body but is brittle, and it fractures rather than deforming.

A broken filling often leaves a sharp margin, either of the remaining material or of the unsupported tooth around it. This is one of the most common causes.

Decay undermines enamel from beneath. The surface eventually collapses, leaving thin, sharp remnants at the edge of the cavity. Because tooth decay often produces no symptoms until this point, the sharp edge can be the first thing you notice.

Bruxism wears teeth unevenly and creates sharp, chipped incisal edges on front teeth in particular. It is also a major cause of restorations fracturing. A night guard addresses the underlying habit.

A fall, a sporting knock or an accident. Our article on urgent care after a broken tooth covers this in detail.

The tongue is one of the most densely innervated structures in the body and is mapped to a disproportionately large area of the sensory cortex. It detects changes in the shape of your teeth far below the threshold of what you could see, and it is strongly drawn to anything unfamiliar.

That is where the problem lies. Every time the tongue investigates the sharp edge, the lateral border is abraded. Repeated over hours, this produces a traumatic ulcer — a shallow, painful lesion at the exact point of contact.

Traumatic ulcers are painful out of proportion to their size, because they are constantly bathed in saliva and disturbed by speech and eating. Crucially, they cannot heal while the cause remains, which is why people can spend weeks with a sore tongue that keeps almost getting better.

Once the sharp edge is covered or smoothed, most traumatic ulcers settle within a week to ten days.

There is one caveat worth stating plainly: any ulcer that persists for more than three weeks should be examined, even where a cause seems obvious.

• Cover the sharp edge. Dry the tooth first — wax will not adhere to a wet surface. Roll a small piece into a ball and press it over the edge. Replace it after meals

• If you have no wax, sugar-free chewing gum pressed over the edge is a reasonable substitute

• Rinse with warm salt water — half a teaspoon in a glass of warm water — several times a day, particularly after eating

• Manage discomfort with over-the-counter pain relief if suitable for you. A protective ulcer gel from a pharmacy can help. Never place aspirin against the gum or the ulcer

• Avoid aggravating the area. Acidic food and drink, spicy food, salty snacks, crisps and very hot items all sting an ulcerated tongue. Alcohol-containing mouthwash does the same

• Keep brushing gently, including near the sore area, and use a soft brush

• Try consciously not to explore it with your tongue — difficult, but it reduces the abrasion

Do not attempt to file the tooth with a nail file or emery board. These are unsterile, damage enamel, and can worsen the fracture without addressing the underlying problem.

Smoothing and polishing. For a small chip, the edge is smoothed with fine instruments and polished. This is quick, usually requires no anaesthetic and frequently no drilling of sound tooth. In many cases it is all that is needed.

Composite bonding. Where enough tooth has been lost that smoothing would leave an obvious notch, tooth-coloured material is bonded and shaped to restore the contour. Completed in one visit. Our article on why bonding feels rough at first explains what to expect afterwards.

White filling replacement. Where a broken restoration or decay is the cause.

Dental crown or onlay. Where a substantial portion of the tooth has fractured or the remaining walls are weakened.

Porcelain veneers. For front teeth with more extensive edge damage, particularly where several teeth are involved.

Addressing the underlying cause. This is the part that prevents recurrence — a night guard for grinding, treatment of decay, replacing failing restorations, or occasionally adjusting the bite where a particular tooth is taking excessive load.

Book an appointment if:

• A sharp edge is repeatedly cutting your tongue or cheek

• You have a chipped tooth or a broken tooth

• A filling has broken or come out

• The ulcer has not started improving within a few days of covering the edge

• Any ulcer persists beyond three weeks — this should always be assessed

• You have tooth sensitivity at the fractured tooth

• Bleeding from the tongue does not settle

Seek urgent care through an emergency dentist if you have severe toothache, facial or jaw swelling, fever, or bleeding that will not stop.

• Wear a night guard if you grind

• Do not bite ice, boiled sweets, nut shells, olive stones or packaging

• Do not use your teeth to open things or hold objects

• Wear a custom mouthguard for contact sport

• Clean between the teeth daily to prevent decay at filling margins

• Attend routine check-ups so weakened cusps and crack lines can be spotted before they fracture

• Attend hygiene appointments at your recommended interval

• Report a rough edge early, while smoothing is still all that is needed

• Dental wax over the edge gives immediate relief and lets the ulcer heal

• A traumatic ulcer cannot heal while the sharp edge is still in contact

• Never file a tooth yourself

• Most traumatic ulcers settle within a week to ten days once the cause is removed

• Any ulcer lasting more than three weeks needs assessment

• Smoothing is often a very short appointment with no drilling of sound tooth

• Grinding, decay and failing fillings are the common underlying causes

The NHS guidance on caring for your teeth and gums covers day-to-day oral care.

If your tongue is sore, the fastest useful thing you can do is dry the tooth and put wax over the edge. Relief is immediate and the ulcer can finally start healing.

The appointment itself is usually short. What is worth spending a few extra minutes on is why the edge appeared — because if the answer is grinding or an old failing restoration, smoothing this one will not be the last time.

To have a sharp tooth edge treated, book an appointment at 22 Wimpole St, London W1G 8GQ, or call 020 7183 0692.

Dental symptoms and treatment options should always be assessed individually during a clinical examination.

This article is for general educational information only and is not professional dental advice, diagnosis, or a treatment recommendation. Information here is general and cannot replace an in-person assessment by a qualified, GDC-registered dental professional. Symptoms, suitability, fees, timelines, and outcomes vary according to individual clinical circumstances. If you have pain, swelling, or other concerning symptoms, seek prompt professional dental care. Always request a written treatment plan and cost estimate before proceeding with treatment.

Written Date: 25 August 2026 Next Review Date: 25 August 2027