October 4, 2025

Mouth ulcers are small, painful sores that can make eating, drinking, and talking uncomfortable. They’re often caused by irritation — like accidentally biting your cheek, sharp teeth, or friction from a denture — but sometimes they can appear without a clear reason. Most heal naturally within a week or two, but if an ulcer lasts longer than three weeks, it’s important to have it checked by your dentist. Persistent or recurring ulcers may be linked to other health conditions, so early evaluation helps ensure proper care and peace of mind.

Mouth Ulcers Causes and Treatment: When to See a Dentist

In this episode of the Iconic Smiles Podcast, Dr. Gerdan Lamorell breaks down everything you need to know about mouth ulcers — from their causes and symptoms to when you should seek professional care. If you’ve ever wondered why mouth ulcers appear, how to treat them, or when they might signal something more serious, this episode delivers clear, evidence-based answers.

What Are Mouth Ulcers?

Mouth ulcers are painful sores that develop inside the mouth, often appearing red or yellow. They differ from cold sores, which occur outside the lips and are caused by a viral infection. While they’re common and usually harmless, their discomfort can interfere with eating, speaking, and daily life.

Common Causes of Mouth Ulcers

Dr. Lamorell explains that the most common mouth ulcers causes include:

• Trauma or irritation — accidentally biting your cheek or tongue, sharp teeth, vigorous brushing, or poorly fitting dentures.
• Recurrent aphthous stomatitis (canker sores) — multiple ulcers that appear without an obvious cause, more common in children and young adults.

These are the two main categories:

• Traumatic ulcers: typically single, located near the source of irritation, and heal once the cause is removed.
• Recurrent ulcers: appear repeatedly, often in clusters, and may relate to the immune system or nutritional deficiencies.

Types of Mouth Ulcers

Mouth ulcers vary in size, number, and severity. Dr. Lamorell identifies three main types:

• Minor ulcers: The most common, about the size of a pencil eraser. They appear on the cheeks, gums, lips, or tongue and heal within 1–2 weeks.
• Major ulcers: Larger, deeper, and slower to heal — often lasting more than three weeks and requiring professional evaluation.
• Herpetiform ulcers: Clusters of tiny, painful ulcers that can number up to 100 at a time; though uncommon, they can significantly affect comfort and quality of life.

Any ulcer lasting longer than three weeks should be checked by your dentist.

Less Common Mouth Ulcers Causes

While most ulcers are harmless, less common causes include:

• Viral or bacterial infections
• Anemia and blood disorders
• Skin or gastrointestinal diseases
• Autoimmune conditions

In some cases, mouth ulcers may be the first sign of an underlying systemic condition, so persistent or recurring sores shouldn’t be ignored.

Can Mouth Cancer Cause Mouth Ulcers?

Yes — though rare, mouth cancer can initially present as a single, non-healing ulcer.

Warning signs include:

• Ulcers lasting longer than 2–3 weeks
• No clear cause (such as trauma or irritation)
• Ulcers on or under the tongue
• Associated habits such as smoking or heavy alcohol use, which greatly increase risk

If you notice these symptoms, schedule a dental examination immediately. Early detection saves lives.

Are Mouth Ulcers Contagious?

No — mouth ulcers are not contagious. You can’t catch them by kissing or sharing drinks. They are not caused by viruses like cold sores and cannot be spread from person to person.

Treatment for Mouth Ulcers

The right treatment depends on the cause:

• For traumatic ulcers, your dentist may smooth a sharp tooth or adjust a denture.
• For recurrent ulcers, medicated mouthwashes, gels, or nutritional supplements may help.
• Persistent or painful ulcers may require prescription anti-inflammatory or antimicrobial rinses.

If your ulcer lasts longer than two weeks, see your dentist or doctor for evaluation and potential testing.

Preventing Mouth Ulcers

You can reduce your risk of developing mouth ulcers with these habits:

• Maintain excellent oral hygiene
• Use a soft, high-quality toothbrush to avoid trauma
• Eat a balanced diet rich in vitamins A, C, and E
• Limit tobacco and alcohol use
• Visit your dentist regularly for oral cancer screenings and preventive care

When to See a Dentist About Mouth Ulcers

Dr. Lamorell’s “Golden Rules” for mouth ulcers are:

1. See your dentist or doctor if an ulcer lasts more than 2–3 weeks.
2. Seek medical attention if you feel unwell or have ulcers elsewhere (eyes, skin, genitals).
3. Consult your dentist if ulcers frequently return — this may indicate an underlying condition.

Being proactive and observant ensures early treatment and peace of mind.

Key Takeaways

• Most mouth ulcers heal naturally within one to two weeks.
• Persistent ulcers lasting more than three weeks should always be checked by a dentist.
• Good oral hygiene, balanced nutrition, and regular dental visits are your best defenses.
• Early detection of non-healing ulcers can prevent serious complications, including oral cancer.

Call to Action

If you’re experiencing painful or recurring mouth ulcers, don’t wait. Schedule an appointment with Dr. Gerdan Lamorell to identify the cause and get the relief you need.

Listen to the full episode and book your consultation here.

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