Mouth Ulcers (Canker Sores)

What Causes Mouth Ulcers?

Mouth ulcers (canker sores) are small, painful lesions that develop on the soft tissues inside your mouth or at the base of your gums. While most are harmless and heal on their own within 1-2 weeks, recurring or unusually large ulcers may need professional attention.

Common Causes

• Minor injuries from dental work, biting your cheek, or hard brushing
• Sensitivity to acidic or spicy foods
• Stress or lack of sleep
• Vitamin deficiencies (B12, iron, folate)
• Hormonal changes
• Ill-fitting dentures or orthodontic appliance irritation
• Underlying conditions like celiac disease or Crohn's disease

When to See a Dentist

See a dentist if ulcers are unusually large, keep coming back, last longer than 3 weeks, are spreading, cause severe pain that interferes with eating or drinking, or are accompanied by fever. Persistent sores should always be evaluated to rule out oral cancer.

Treatment and Prevention

We can prescribe medicated mouth rinses, topical treatments, or recommend dietary changes to help manage recurring ulcers. If your ulcers are caused by dental appliances, we can adjust them for a better fit. We also perform oral cancer screenings as part of our comprehensive exams.

Home Remedies for Mouth Ulcers

Most mouth ulcers heal on their own within one to two weeks, but you can speed up the process and reduce pain with simple home remedies. Rinsing with warm salt water (half a teaspoon in eight ounces of water) several times a day helps cleanse the sore and reduce inflammation. Applying a small amount of milk of magnesia directly to the ulcer three to four times daily can coat and protect it. Avoid spicy, acidic, and salty foods that irritate the sore — stick to soft, bland foods while it heals. Over-the-counter topical gels containing benzocaine can numb the area and make eating more comfortable. Drinking through a straw can help bypass the ulcer when consuming acidic beverages. If you notice that ulcers appear after eating certain foods, keep a food diary to identify triggers. Ensuring adequate intake of B vitamins, iron, and folic acid through diet or supplements may help prevent recurring sores. For ulcers caused by irritation from Invisalign or braces, dental wax can provide a protective barrier.

When Ulcers Could Be Serious

While most mouth ulcers are harmless canker sores, some oral lesions require immediate professional evaluation. A mouth sore that has not healed within three weeks should be examined by a dentist, as persistent sores can be an early sign of oral cancer. Other warning signs include ulcers that are unusually large (over one centimetre), sores that are painless (cancerous lesions are often painless in early stages), white or red patches on the tongue or lining of the mouth, difficulty swallowing or moving the tongue, and unexplained numbness in the mouth or lips. At Redwater Dental Clinic, we include oral cancer screenings as part of every routine examination. Early detection of oral cancer dramatically improves treatment outcomes. If you have a mouth sore that concerns you, do not wait — call 780-942-4691 for a prompt evaluation.