If you’ve ever had a painful little sore inside your mouth that made eating or talking uncomfortable, chances are it was a canker sore. These small but mighty irritations are very common — and although they usually go away on their own, they can be frustrating while they last.
Here’s what you need to know about what causes canker sores, how to manage them at home, and when to talk to your dentist.
What Are Canker Sores?
Canker sores (also called aphthous ulcers) are small, shallow ulcers that form inside the mouth — typically on the inner cheeks, lips, tongue, or the soft palate.
They are not contagious, unlike cold sores, which are caused by the herpes virus and appear outside the mouth.
Canker sores usually look like:
- A round or oval ulcer with a white or yellow centre
- A red border around the sore
- Usually less than 1 cm in diameter
- Can appear singly or in small clusters
Common Symptoms
- Sharp or burning pain, especially when eating, drinking, or brushing
- Mild swelling around the sore
- Temporary difficulty speaking or chewing (in more severe cases)
Most canker sores heal on their own within 7–14 days.
What Causes Canker Sores?
The exact cause isn’t always clear, but several triggers may contribute:
- Stress or lack of sleep
- Minor mouth injuries (e.g., biting the inside of your cheek, braces, dental work)
- Acidic or spicy foods (like citrus fruits or hot sauces)
- Vitamin deficiencies, especially B12, iron, or folate
- Hormonal changes
- Food sensitivities (e.g., to gluten or sodium lauryl sulfate in toothpaste)
- In rare cases, autoimmune conditions or gastrointestinal diseases (like celiac or Crohn’s)
How to Treat Canker Sores
Most canker sores will heal on their own — but there are ways to relieve the discomfort and promote healing:
✅ 1. Rinse with salt water or baking soda
Mix 1 tsp of salt or baking soda with warm water and gently swish for 30 seconds. This helps reduce bacteria and soothe irritation.
✅ 2. Use over-the-counter oral gels
Products like benzocaine (Orajel®, Anbesol®) can provide temporary numbing relief.
✅ 3. Avoid spicy, salty, or acidic foods
Stick to soft, bland foods until the sore heals.
✅ 4. Use a soft-bristled toothbrush
This prevents further irritation. Avoid whitening toothpastes or those with harsh foaming agents (like sodium lauryl sulfate).
✅ 5. Apply ice chips
Letting ice dissolve slowly in the mouth can help reduce pain and inflammation.
When to See a Dentist
Book a visit with your dentist if:
- A canker sore lasts longer than two weeks
- You’re getting frequent or severe outbreaks
- The sore is unusually large or painful
- You’re having difficulty eating, drinking, or speaking
- There are other symptoms like fever, swollen lymph nodes, or fatigue
Your dentist may recommend a prescription mouth rinse, topical steroid, or refer you to a physician if there’s an underlying condition.
Can Canker Sores Be Prevented?
While not all canker sores can be prevented, here are some helpful tips:
- Manage stress with relaxation techniques
- Maintain a balanced diet with enough iron, B12, and folate
- Use non-irritating toothpaste
- Protect your mouth during sports or dental treatments
- Stay hydrated and avoid overly spicy or acidic foods if you’re prone to sores
Final Thoughts
Canker sores are a common (and uncomfortable) part of life for many people — but with the right care, they’re manageable. If you’re dealing with frequent or stubborn sores, don’t hesitate to talk to your dentist. A simple check-up can rule out more serious issues and help you find long-term relief.
Dealing with mouth pain or recurring canker sores? We’re here to help.
Our team provides gentle, professional care and personalized advice for all your oral health concerns. Book a consultation today and get the relief and guidance you need to feel your best.