Mouth ulcers are small sores that can develop on the gums, tongue, cheeks, or lips. They’re often painful, especially when eating or talking, and can make the mouth feel sensitive.
Mouth ulcers are one of the many symptoms covered in our Common Concerns section, which explains common mouth and dental problems and when reassurance is enough.
What usually causes mouth ulcers?
Mouth ulcers are commonly caused by minor irritation inside the mouth, such as accidental biting, stress, or sensitivity to certain foods. Most ulcers are harmless and heal within one to two weeks. Ulcers that persist or recur frequently should be assessed professionally.
Mouth ulcers are usually minor injuries or reactions affecting the soft tissues of the mouth and are different from conditions that cause swollen gums, which involve inflammation of the gum tissue itself.
An ulcer doesn’t automatically indicate infection or serious disease, particularly if it’s small and short-lived.
Dentists often see mouth ulcers linked to:
Minor trauma, such as biting the inside of the cheek or irritation from dental appliances, is one of the most frequent triggers of mouth ulcers. Often, the exact cause isn’t clear, and ulcers may recur from time to time.
People with mouth ulcers may notice:
Sensitivity when brushing nearby areas can feel similar to bleeding gums, but ulcers are usually localised sores rather than widespread gum irritation.
Ulcers are often more noticeable because of the pain they cause.
It may be reasonable to monitor the situation if:
The ulcer is small and improving
Healing begins within a week
Pain is manageable
No other symptoms are present
Most mouth ulcers heal on their own without treatment.
It’s sensible to book a dental visit if:
An ulcer lasts longer than two weeks
Ulcers recur frequently
Pain is severe or worsening
You notice swelling, fever, or difficulty eating
You’re unsure whether a sore is an ulcer
Ongoing discomfort, especially if accompanied by a bad taste or bad breath, should be checked to rule out infection or other causes.
When you see a dentist about mouth ulcers, they typically:
Examine the ulcer’s size, shape, and location
Ask how long it’s been present
Check for local irritation or trauma
Review medical history if relevant
Advise on monitoring or further steps
Most assessments focus on reassurance and healing.
Mouth ulcers are common and usually harmless. While they can be painful, they often resolve on their own.
Knowing when to monitor and when to seek advice can help you manage them with confidence.
Most mouth ulcers heal within one to two weeks without treatment. If an ulcer lasts longer than three weeks, professional advice is recommended.
Common mouth ulcers are not contagious. However, certain viral infections that cause sores may spread.
Recurring ulcers may be linked to stress, nutritional deficiencies, minor trauma, or underlying medical conditions. Persistent recurrence should be discussed with a healthcare professional.
Seek advice if the ulcer is unusually large, extremely painful, persists beyond three weeks, or is accompanied by other symptoms.
Clear, calm dental explanations to help you understand symptoms, treatments, and what to expect without pressure or judgment.
© 2026 OralJourney. All rights reserved.
Professional dental nurse resources: dentalnursehub.com
Educational content only. Not a substitute for professional dental advice, diagnosis, or treatment.
Designed by oraljourney.com