Mouth Ulcers: Causes, How to Relieve Them & When to See a Dentist

A mouth ulcer is a small, painful sore inside the mouth, usually found on the cheeks, lips, tongue or gums. Most mouth ulcers are harmless and heal on their own within 1 to 2 weeks, although they can cause discomfort when eating, drinking and speaking.

Mouth ulcers can occur for several reasons, including minor injuries, stress or nutritional deficiencies. Understanding the possible causes, how to relieve discomfort and when to see a dentist can help you manage them more effectively.

Common Causes of Mouth Ulcers in Everyday Life

Mouth ulcers can develop due to various triggers, many of which are related to everyday habits and routines.

Spicy and acidic foods are common triggers. Bird’s eye chillies, sambal, curry and other spicy foods can irritate the soft lining inside the mouth, especially if there is already a small wound or sensitive tissue. Acidic fruits such as pineapple and oranges, as well as some fruit juices, can have a similar effect.

Accidentally biting the inside of your cheek or tongue is another common trigger. This can happen when you eat too quickly or talk while chewing. Minor injuries like these can cause an ulcer to develop.

Other common causes include:

Stress and lack of sleep — Some people find that mouth ulcers appear more frequently when they are stressed or sleep-deprived.
Nutritional deficiencies — Low levels of nutrients such as iron, vitamin B12 or folate may be associated with recurring mouth ulcers.
Toothpaste that is too harsh — Some toothpastes contain an ingredient called sodium lauryl sulphate (SLS), which may irritate the mouth lining in some individuals.
Hormonal changes — Women may experience mouth ulcers during their menstrual cycle or pregnancy.
Dental treatment or braces — Sharp edges on dental fillings, braces or dentures can rub against the cheeks or gums and cause sores.

Dehydration can also be a contributing factor, particularly in Malaysia’s hot weather. Not drinking enough water throughout the day can cause dry mouth and make the tissues more prone to irritation.

How to Relieve Mouth Ulcers

Most mouth ulcers do not require prescription medication to make you more comfortable. Several simple measures can help reduce pain and discomfort while the ulcer heals.

Rinse with salt water — Dissolve half a teaspoon of salt in a glass of warm water, rinse for about 30 seconds and then spit it out. You can repeat this several times a day. Salt water may sting when it comes into contact with the ulcer, so stop if it causes significant discomfort.
Choose soft foods — Porridge, soft rice, yoghurt and other easy-to-chew foods can make mealtimes more comfortable while the ulcer heals.
Keep your mouth clean — Continue brushing your teeth with a soft-bristled toothbrush as part of your daily oral hygiene routine. Be gentle around the ulcer to avoid causing additional irritation.
Stay hydrated — Drink enough water to keep your mouth comfortable, especially if your mouth feels dry or sore.
Try cold foods or drinks — Cold water or chilled soft foods may provide temporary relief and make eating and drinking more comfortable.
Consider SLS-free toothpaste — If you frequently develop mouth ulcers, toothpaste without sodium lauryl sulphate (SLS) may help reduce irritation for some individuals.
Use over-the-counter oral products — Certain oral gels or mouthwashes may provide temporary relief while the ulcer heals. Ask a pharmacist or dentist about suitable options for you.
Check for sources of irritation — Braces, dentures, sharp fillings or other dental treatments can sometimes rub against the inside of the mouth. If you notice recurring irritation in the same area, a dentist can examine it and address the underlying cause.

What to Avoid Temporarily

When you have a mouth ulcer, certain foods and habits can make the discomfort worse. Try to avoid:

Spicy foods — This includes sambal for the time being. Chilli and other spices can irritate the ulcer and increase pain.
Acidic foods and drinks — Fruit juices, citrus fruits and carbonated drinks can cause stinging and interfere with the healing process.
Hot drinks — Allow coffee or teh tarik to cool slightly before drinking, as heat can make the ulcer more uncomfortable.
Hard or crunchy foods — Crackers, crispy biscuits, toast and foods with rough textures can rub against the ulcer and cause further irritation.
Toothpaste containing SLS — If you frequently develop ulcers, consider switching to a gentler, SLS-free toothpaste.

Merokok juga boleh melambatkan proses penyembuhan, jadi sebaiknya kurangkan atau elakkan merokok ketika mengalami ulser.

How Can a Dentist Help Treat Mouth Ulcers?

Most mouth ulcers heal on their own within 1–2 weeks. You should consider seeing a dentist if your ulcer:

Lasts for more than 2–3 weeks
Keeps coming back
Is unusually large or painful
Makes it difficult to eat or drink
Bleeds or becomes increasingly swollen
Occurs together with other symptoms such as fever
Shows no signs of healing even after the source of irritation has been removed

A dentist will examine the ulcer and look for possible causes, such as irritation from braces, dentures, fillings or accidentally biting the inside of the cheek.

If treatment is needed, the dentist may recommend products or medication to help reduce pain and inflammation and support the healing process. If the ulcer is caused by a dental appliance or another source of irritation, the dentist can also help address the underlying cause.

If a mouth ulcer does not heal or keeps recurring, a dental examination can help identify the cause and ensure that you receive appropriate treatment.

Managing Mouth Ulcers

Mouth ulcers may be small, but they can interfere with everyday activities. Eating, drinking and speaking can become uncomfortable. The key is to maintain good oral hygiene, avoid known triggers and give the ulcer time to heal.

In most cases, rinsing with salt water, choosing soft foods and allowing the ulcer time to heal are enough. However, if an ulcer lasts for more than three weeks, do not ignore it. A dentist can examine the condition and help identify the cause and appropriate treatment.