A canker sore can turn a normal day into a painful one fast. Coffee stings. Toothpaste burns. A crunchy chip hits the wrong spot and ruins lunch. Most people have had at least one, but when mouth sores keep coming back, last longer than expected, or make it hard to eat, it is worth understanding what may be causing them.
Canker sores are small ulcers that form inside the mouth. They often appear on the inside of the lips or cheeks, under the tongue, along the soft palate, or near the gum tissue. They usually look white, yellow, or gray in the center with a red border. They are not the same as cold sores, which usually appear on or around the lips and are caused by a virus.
Canker Sores vs. Cold Sores
This distinction matters. Canker sores are not contagious. You cannot spread them by sharing a drink, kissing, or touching the area. Cold sores are contagious and may start with tingling or burning before blisters appear near the lip. If you are not sure which one you have, a dental exam can help you sort it out.
Common Canker Sore Triggers
There is not one single cause for every patient. For some people, canker sores flare during stress, poor sleep, illness, or hormonal changes. Others notice a connection with acidic foods, spicy foods, citrus, cinnamon flavoring, or certain toothpastes. A small injury from a toothbrush, sharp chip, dental appliance, or accidental cheek bite can also set one off.
Nutrition and medical factors can play a role too. Low iron, B12, folate, immune conditions, gastrointestinal disease, and some medications may be linked with recurring mouth ulcers. That does not mean every canker sore signals a major problem, but a pattern is worth discussing.
When a Mouth Sore Needs Attention
Call for an exam if a sore lasts more than two weeks, keeps returning in the same spot, is unusually large, bleeds, appears with fever or swelling, or makes it hard to eat and drink. Slow-healing mouth sores should not be ignored.
What Helps at Home
Most small canker sores heal on their own within 7 to 14 days. While they heal, the goal is to reduce irritation and keep the area clean. Use a soft toothbrush. Avoid spicy, salty, crunchy, and acidic foods. Choose bland foods and cool drinks when the sore is tender. If toothpaste burns, ask your dental team whether a sodium lauryl sulfate free toothpaste may be worth trying.
Do not scrape or pop the sore. That delays healing and can make pain worse. Over the counter protective gels may help shield the area before meals. Warm saltwater rinses can feel soothing for some patients, although they may sting at first. If sores are severe or frequent, prescription rinses or topical medication may shorten the painful phase. Keeping a simple note of foods, stress, sleep, and toothpaste changes can also reveal patterns.
How a Dentist Can Help
At Elite Dental Smiles, we look at the location, size, shape, history, and healing pattern of the sore. We also check for broken teeth, rough fillings, sharp edges, gum infection, bite trauma, appliance irritation, and signs that the sore may not be a routine canker sore.
If the sore appears typical, we can help you manage pain and identify triggers. If it is unusual, persistent, or suspicious, we may recommend additional evaluation. That is not meant to scare patients. It is simply good oral health care. The mouth often gives early warning signs, and early evaluation is always better than waiting months.
Common Questions About Canker Sores
Are canker sores contagious?
No. Canker sores are not contagious. Cold sores are different and can spread through close contact.
How long should a canker sore last?
Most small canker sores heal within 7 to 14 days. Sores that last longer than two weeks should be checked.
Can dental work cause canker sores?
Dental work does not usually cause canker sores directly, but tissue irritation, cheek biting, or stress can trigger them in people who are prone to outbreaks.
What helps canker sore pain?
Avoid spicy or acidic foods, use a soft toothbrush, keep the area clean, and ask your dentist about protective gels or prescription rinses if sores are severe.
When should I call Elite Dental Smiles about a mouth sore?
Call if a sore lasts more than two weeks, keeps coming back, is unusually large, bleeds, appears with fever, or makes eating and drinking difficult.
Have a Mouth Sore That Will Not Heal?
Call Elite Dental Smiles for an exam and a clear plan to protect your oral health.