Mouth Ulcers (Aphthous Ulcers): Causes and Management Options
Mouth ulcers are small sores that develop on the soft tissues inside the mouth. They may appear on the cheeks, lips, tongue, or gums and can cause discomfort, especially during eating or speaking.
Many ulcers heal naturally, but recurrent or persistent ulcers may benefit from professional evaluation to help identify possible underlying factors and guide appropriate care.
Professional Assessment
A thorough clinical evaluation can assess the mouth, identify potential sources of irritation, and help determine the most appropriate course of care.
“I’d been getting mouth ulcers repeatedly — the team identified a rough filling that was causing the problem.”
What Are Mouth Ulcers (Aphthous Ulcers)?
Aphthous ulcers are small, round or oval sores that form on the soft tissues inside the mouth. They typically appear with a white or yellow centre and a red border, and may develop on the inner cheeks, lips, tongue, or gums. The condition may cause tenderness or irritation, particularly when eating, drinking, or speaking.
Common Presentation
Most aphthous ulcers are small — typically a few millimetres in diameter — and appear as shallow, well-defined sores on the soft mucosal tissues. They may occur singly or in small clusters. The surrounding tissue is usually inflamed and tender, and the ulcer itself may be painful when touched or when food comes into contact with it.
Typical Healing
Most minor aphthous ulcers heal naturally within one to two weeks without leaving a scar. During the healing period, the ulcer may be uncomfortable but should gradually become less painful. Ulcers that persist beyond this timeframe, or that are unusually large, may benefit from professional assessment to rule out other causes.
Not Usually Infectious
Aphthous ulcers are not caused by infection and are not contagious. They differ from cold sores, which are caused by the herpes simplex virus and typically appear on the outer lip. Not all mouth ulcers are related to serious health problems, though recurrent episodes may sometimes warrant further investigation.
A can evaluate the oral tissues, identify any potential sources of irritation, and help determine the most appropriate course of care for mouth ulcers.
Common Causes of Mouth Ulcers
Mouth ulcers may develop due to a range of contributing factors. In many cases, more than one factor may be involved simultaneously. Understanding the possible causes can help guide appropriate assessment and management.
1Minor Injury to the Mouth
Accidental biting of the cheek, lip, or tongue is one of the most common triggers for mouth ulcers. Minor trauma from vigorous tooth brushing, eating hard or crunchy foods, or inadvertently catching the soft tissues can damage the mucosal surface and lead to ulcer formation. These ulcers typically develop within a day or two of the injury.
2Irritation from Sharp Tooth Edges or Appliances
Sharp or rough edges on teeth — whether from chipping, wear, or decay — can repeatedly rub against the soft tissues of the mouth. Similarly, dental appliances such as dentures, braces, or retainers that do not fit properly may cause localised irritation and contribute to ulcer development. Professional adjustment may help address these issues.
3Stress or Fatigue
Periods of heightened stress, anxiety, or physical fatigue are commonly associated with increased frequency of mouth ulcers in some individuals. The precise mechanism is not fully understood, but stress may affect immune function and the body's ability to maintain healthy mucosal tissues. Managing stress may help reduce recurrence in susceptible individuals.
4Nutritional Factors
Deficiencies in certain nutrients — including iron, vitamin B12, folate, and zinc — have been associated with recurrent mouth ulcers in some studies. While nutritional deficiency is not the cause in every case, ensuring adequate intake of these nutrients through diet may be relevant. Your dentist or doctor can advise on whether further investigation may be appropriate.
5Hormonal Changes
Some individuals notice that mouth ulcers coincide with hormonal fluctuations, such as during menstruation. While the relationship between hormonal changes and ulcer development is not fully established in all cases, it is a recognised pattern for some people. Awareness of these patterns can help in discussions with healthcare professionals.
6Certain Foods
Some individuals find that particular foods appear to trigger or exacerbate mouth ulcers. Commonly reported triggers include acidic fruits (such as citrus), spicy foods, chocolate, coffee, and certain preservatives. Sensitivity varies between individuals, and identifying personal dietary triggers may help manage the frequency of ulcers.
Multiple factors may contribute to mouth ulcer development simultaneously. Professional assessment can help identify which factors may be most relevant in your individual case.
When Mouth Ulcers May Need Professional Assessment
While most mouth ulcers are minor and heal without intervention, certain signs may suggest that professional evaluation could be helpful. Assessment can determine whether underlying factors are contributing and whether any preventive measures may be appropriate.
Ulcers That Persist Longer Than Expected
Most minor aphthous ulcers heal within one to two weeks. If a mouth ulcer persists beyond two to three weeks, professional assessment may be appropriate to evaluate the sore and rule out other potential causes.
Frequent or Recurrent Episodes
If you experience mouth ulcers frequently — for example, new ulcers developing before previous ones have fully healed, or episodes occurring every few weeks — this pattern may warrant investigation to identify possible contributing factors.
Unusually Large or Painful Sores
While most aphthous ulcers are small, some individuals develop larger sores (sometimes called major aphthous ulcers) that may be deeper, more painful, and slower to heal. These may benefit from professional evaluation and clinical management.
Difficulty Eating, Drinking, or Speaking
If mouth ulcers are significantly affecting your ability to eat, drink, or speak comfortably, professional assessment can help evaluate the situation and discuss management options that may help improve comfort.
When to Seek Assessment
Professional evaluation may be helpful if you notice any of the following. These signs do not necessarily indicate a serious problem, but timely assessment can support informed decisions about care.
A mouth ulcer that has not healed within two to three weeks
Ulcers that recur frequently or develop in clusters
Sores that are unusually large, deep, or painful
Difficulty eating, drinking, or speaking due to ulcers
Ulcers accompanied by other symptoms such as fever or fatigue
New ulcers developing in the same location repeatedly
Assessment and advice for mouth ulcers are available at our London clinic, where professional evaluation can help identify possible underlying causes.
Oral Health Factors Linked to Recurrent Ulcers
While mouth ulcers have many possible causes, certain dental and oral health factors may contribute to irritation of the oral tissues and increase the likelihood of ulcer formation. Professional dental care may help address these underlying factors.
Identifying and managing dental sources of irritation can be an important part of reducing the recurrence of mouth ulcers for some individuals.
Potential Dental Contributing Factors
Rough, sharp, or chipped tooth edges can repeatedly irritate the soft tissues of the cheeks, lips, or tongue. Similarly, worn, fractured, or rough fillings may create areas of friction that contribute to ulcer development. Smoothing these surfaces through tooth contouring or restoration repair may help reduce irritation.
Poor oral hygiene leading to plaque build-up may contribute to inflammation of the gum tissues. Inflamed or irritated gum tissue may be more susceptible to ulcer formation. Regular professional cleaning and good home care routines can help maintain healthy oral tissues.
Dentures, orthodontic braces, retainers, or other dental appliances that do not fit correctly may rub against the soft tissues and cause localised trauma. This repeated irritation can trigger ulcer formation in the areas of contact. Professional adjustment of the appliance may help resolve the issue.
Occasionally, mouth ulcers may develop following dental treatment — for example, from contact with dental instruments or from the placement of new restorations. These ulcers are usually temporary and heal as the tissues recover. If irritation persists, professional review can assess whether adjustment is needed.
Preventive and Professional Care
Managing mouth ulcers involves identifying and addressing contributing factors where possible. Regular dental examinations and professional care can play an important role in monitoring oral health and reducing the frequency of recurrent ulcers.
Monitoring and Preventive Measures
Regular dental examinations help monitor oral health and identify potential sources of irritation before they become problematic.
Good oral hygiene — including gentle brushing with a soft-bristled toothbrush and regular flossing — helps maintain healthy mucosal tissues.
Being aware of personal triggers — such as certain foods, stress, or fatigue — may help some individuals reduce the frequency of ulcers.
Ensuring adequate nutritional intake, particularly of iron, vitamin B12, and folate, may be relevant for individuals with recurrent ulcers.
Professional Treatment Options
Where dental factors are contributing to recurrent ulcers, your dentist may recommend addressing the source of irritation. This could include to smooth rough edges, repair or replacement of damaged restorations, or adjustment of dental appliances.
If a sharp or chipped tooth is contributing to ulcers, or may be considered to restore smooth contours and reduce tissue irritation.
Professional evaluation determines the most appropriate care for each individual. Treatment depends on clinical findings and the specific factors contributing to ulcer development.
Temporary Measures Before Assessment
If you are experiencing a mouth ulcer, the following general measures may help manage comfort while professional assessment is arranged. These do not replace professional dental care.
Recommended
Avoid foods that may irritate the ulcer, such as spicy, acidic, salty, or very hot items.
Maintain gentle oral hygiene to keep the mouth clean and support natural healing.
Use a soft-bristled toothbrush to reduce further irritation to the affected area.
Drink plenty of water and choose softer foods if chewing is uncomfortable.
Arrange professional dental assessment if ulcers persist beyond two to three weeks or recur frequently.
Avoid
Do not attempt to scrape, pick at, or remove the ulcer — this may worsen the sore and delay healing.
Avoid using harsh or alcohol-based mouthwashes on the affected area, as these may cause further irritation.
Do not ignore persistent ulcers that last longer than two to three weeks — professional assessment is recommended.
Avoid very hot beverages or foods that may aggravate the ulcer and increase discomfort.
Do not stop brushing around the area entirely — gentle cleaning helps maintain oral hygiene and supports healing.
These measures are general guidance only and do not replace professional dental care. If you are concerned about a mouth ulcer, please contact us to arrange an assessment.
Related Treatments
Frequently Asked Questions
Mouth Ulcer Assessment
If you are experiencing persistent or recurrent mouth ulcers, a professional dental assessment can help identify possible causes and determine whether preventive care or treatment may be appropriate.
Professional Mouth Ulcer Assessment
Whether you are experiencing a persistent mouth ulcer, recurrent episodes, or would like to identify possible contributing factors, our South Kensington team can assess your situation and discuss the most appropriate care.
20 Old Brompton Road, South Kensington, London SW7 3DL
Registered & Regulated
Our team are fully registered and regulated for practice in the United Kingdom. Our patients should expect nothing less.
Meet The Experts
Our hand-picked team of clinicians is dedicated to the art and science of your smile.
Dr. Yasha Y Shirazi
Principal Dentist & Clinical Director
GDC: 195843
Meticulous preventative care meets high-quality cosmetic dentistry. Yasha offers complicated surgical extractions, complex treatments, and smile makeovers.
View Profile
Dr. Kamran Yazdi
Dentist
GDC: 197926
Conservative dentistry specialist with postgraduate degrees from UCL Eastman. Believes in preserving as much natural tooth structure as possible.
View ProfileDr. Andreia Phipps
Dentist
GDC: 229601
Friendly and enthusiastic dentist passionate about cosmetic and aesthetic restorative dentistry. Patient-centred care is at the heart of everything she does.
View ProfileDr. Reza Davari
Dentist
GDC: 302422
Award-winning dentist with the London Gold Medal. Combines advanced clinical skill with a calm, gentle manner.
View Profile
Dr. Narges Ameri
Dentist
GDC: 325081
Specialist-trained prosthodontist and implantologist. Former Assistant Professor at Tehran University with expertise in complex restorative cases.
View Profile
Jack Button
Dental Hygienist & Dental Therapist
GDC: 244367
Clinical Director and only Dental Hygienist awarded Fellowship to the International Academy for Dental Facial Esthetics.
View Profile
Laila Alhussein
Dental Hygienist
GDC: 328882
UCL-trained hygienist dedicated to promoting oral health in a warm, welcoming environment. Passionate about patient comfort and connection.
View Profile