Dra. Cléo Salustiano In this article
SummaryMost common causes of mouth soresWhat to do at home and warning signsFAQRead nextMouth Sore: What Could It Be and When to See a Dentist
Quick summary of this article+
Most mouth sores have a simple cause, such as a canker sore, a bite, a burn from hot food, a denture or braces rubbing or a crack at the corner of the mouth, and they heal within about two weeks. When there is a mechanical cause, such as a broken tooth or a loose denture, fixing it at the office is what lets the sore close. A sore that does not heal in about two weeks, feels hard, bleeds easily or comes with a white or red patch needs an assessment. Fever, spreading swelling or difficulty swallowing or breathing call for an emergency room. In Mooca, Dr. Cléo Salustiano (CRO-SP 170844) sees patients every day, from 8 a.m. to 10 p.m.
Most mouth sores have a simple cause and heal on their own within about two weeks: a canker sore, an accidental bite, a toothbrush or hard food that scraped the tissue, a denture or braces rubbing, a palate burnt by hot food, or a crack at the corner of the mouth. The sign that calls for attention is time. A sore that does not heal in about two weeks, keeps coming back in the same spot, feels hard, bleeds easily or comes with a white or red patch needs to be examined by a dentist or doctor.
At the office, many people arrive worried about a sore that, on examination, has a clear mechanical cause: the edge of a broken tooth, a rough filling or a denture that no longer fits well and started to rub. In these cases, treating the cause is usually what lets the sore close. Other times, the lesion is a typical canker sore, which hurts quite a bit but follows a well-known course.
Dr. Cléo Salustiano (CRO-SP 170844), a dentist in Mooca, explains the most common causes of mouth sores, how to tell them apart, what helps at home and which signs call for an assessment or urgent care.
This article comes from Dr. Cléo Salustiano's dental office in Mooca, São Paulo (care in English, Portuguese and Spanish). See the general dentistry page to learn how the treatment is done here and book your assessment.
Most common causes of mouth sores
Canker sore: the most familiar type. It is usually round and shallow, with a whitish or yellowish center and a reddish border, and appears inside the lips or cheeks, under the tongue or on the gums. It hurts, especially with acidic or salty food, and usually heals by itself in one to two weeks. It can be linked to stress, small injuries, hormonal changes or nutritional deficiencies; when it appears very often, it is worth investigating. The article canker sore on the gums has more details.
Injury: accidentally biting the cheek or tongue, a hard toothbrush, crunchy food, a toothpick or the sharp edge of a broken tooth can all cause sores. Dentures and braces can hurt too: a denture that has become loose, a new prosthesis that still needs adjusting, or a bracket or wire that came loose and rubs the cheek. The sore is usually exactly where the friction is and tends to close once the cause is fixed. Never try to file down or adjust a denture or braces at home.
Sore roof of the mouth: the most common cause is a burn from very hot food or drinks, such as pizza, melted cheese or coffee. The area becomes sore, may blister and peel, and usually improves in a few days. A hard, smooth, painless bump in the middle of the palate that has been there for years may be a torus palatinus, a harmless bony growth. Soft, bluish bumps, more common on the lower lip, may be a mucocele, related to a salivary gland. Any new bump that grows or hurts should be checked.
Sore at the corner of the mouth: cracks and redness at the corners of the lips are usually angular cheilitis. Saliva collecting in the skin fold causes irritation and sometimes a fungal or bacterial infection. It is more common in people who lick their lips, wear dentures that have lost height, have dry skin or a nutritional deficiency. Small clustered blisters on the lip that tingle before appearing and keep returning to the same spot suggest cold sores, which are contagious and should be assessed by a dentist or doctor.
| What the sore looks like | Likely cause | What to do |
|---|---|---|
| Round, shallow, white center and red border, painful | Canker sore | Local care; get it checked if it does not heal in about 2 weeks or comes back often |
| Where a tooth, denture or braces touch | Injury or friction | Fix the cause at the office |
| On the palate, after hot food | Burn | Avoid hot and hard food; improves in a few days |
| Hard, smooth, painless bump in the middle of the palate for years | Possible torus palatinus | Show it to your dentist at your next visit |
| Crack and redness at the corner of the mouth | Angular cheilitis | Assessment to find the cause |
| Clustered blisters on the lip that return to the same spot | Possible cold sore | Assessment by a dentist or doctor |
| Sore that does not heal, feels hard or has a white or red patch | Needs investigation | Assessment as soon as possible |
What to do at home and warning signs
While the sore heals, it helps to keep brushing gently with a soft brush, avoid acidic, very salty, spicy, crunchy or very hot food, drink water and avoid touching the sore with your tongue or fingers. Mouthwashes with alcohol may sting. Do not put alcohol, lemon, vinegar, coarse salt, straight baking soda or crushed tablets on the sore, and do not pop blisters. Medications and ointments should only be used as advised by a dentist, doctor or pharmacist and according to the label.
If the sore is caused by a denture, braces, a broken tooth or a rough filling, the treatment is to fix the cause at the office: adjusting or relining the denture, protecting or rebonding a bracket, smoothing or restoring the tooth. If a denture is hurting, leave it out of your mouth as much as you can until the appointment. For other changes in the mouth, such as white coatings, see white tongue: causes and when to see a dentist.
Get an assessment if the sore does not heal in about two weeks, keeps returning to the same spot, is hard, painless and persistent, bleeds easily, or comes with a white or red patch that does not go away, a lump in the neck, numbness or difficulty chewing. Smokers and people who drink alcohol often should pay extra attention. The dentist examines the mouth and, when needed, orders tests or refers you for further investigation. Many sores at once with fever and feeling unwell, especially in children, call for a medical assessment.
Fever, swelling in the face or neck that is spreading, difficulty swallowing, breathing or opening the mouth are emergency signs: go to an emergency room. This content is for information only and does not replace an exam. Consult a dentist if you have any doubt about a sore. In Mooca, Dr. Cléo Salustiano sees patients every day, from 8 a.m. to 10 p.m., including Sundays and holidays, for general dentistry and dental emergencies in Mooca.
What could a mouth sore be?
+
The most common causes are canker sores, accidental bites, a toothbrush or hard food, a denture or braces rubbing, burns from hot food and cracks at the corner of the mouth. Most heal on their own within about two weeks. If the sore does not close in that time or keeps returning to the same spot, get it assessed.
How long does a mouth sore take to heal?
+
Simple sores, such as canker sores and small injuries, usually heal in one to two weeks; mild burns on the palate improve in a few days. If a sore lasts more than about two weeks without closing, it should be examined by a dentist or doctor, even if it does not hurt.
What is the sore at the corner of my mouth?
+
Most often it is angular cheilitis: cracking and redness at the corners of the lips, encouraged by saliva collecting in the skin fold and sometimes by fungi or bacteria. It is more common in people who lick their lips or wear dentures that have lost height. An assessment helps identify and treat the cause.
What is the bump on the roof of my mouth?
+
It depends on what it is like. A hard, smooth, painless bump in the middle of the palate that has been there a long time may be a torus palatinus, a harmless bony growth. A blister after eating something hot is usually a burn. A new bump that grows, hurts or bleeds needs to be examined.
My denture or braces are hurting my mouth. What should I do?
+
Do not try to adjust them at home. If it is a denture, leave it out of your mouth as much as possible until the appointment. With braces, orthodontic wax can protect the cheek for a while. The dentist adjusts or relines the denture or fixes the bracket or wire, and the sore tends to heal afterwards.
When is a mouth sore a concern?
+
When it does not heal in about two weeks, feels hard, bleeds easily, or comes with a white or red patch that does not go away, a lump in the neck or numbness. Fever, spreading swelling or difficulty swallowing or breathing call for an emergency room. Smokers should pay extra attention.
Where can I have a mouth sore checked in Mooca?
+
In Mooca, Dr. Cléo Salustiano (CRO-SP 170844) sees patients at Rua Hipódromo, 1141, near Bresser-Mooca station, Monday to Sunday, from 8 a.m. to 10 p.m., including holidays. She examines the mouth, treats causes such as a broken tooth or a rubbing denture and refers you when needed. Appointments via WhatsApp (11) 97409-7834, in Portuguese, English or Spanish.
