- ADA: mouthhealthy.org
Mouth Sores
Dental health is not limited to your teeth. Sores or irritations can develop in and around the mouth. Fortunately, they usually heal on their own within a week or two. Mouth sores come in several different varieties and can have any number of causes, including:

Infections from bacteria, viruses or fungus
Irritation from a loose orthodontic wire, a denture that doesn’t fit, or a sharp edge from a broken tooth or filling.
The symptom of a disease or disorder.
Some common sores:
Canker Sores
Canker sores develop inside the mouth as small white or gray sores that have a red border. They are not contagious and may occur as one sore or several. Their exact cause is uncertain but some experts believe that immune system problems, bacteria or viruses may be involved. In some cases, trauma to the mouth’s soft tissues can cause a canker sore.
Canker sores usually heal on their own after one or two weeks. Over-the-counter topical anesthetics and antimicrobial mouthwashes may provide temporary relief. Stay away from hot, spicy or acidic foods that can irritate the sore. Antibiotics from your dentist and some oral bandages can reduce secondary infection.
Cold Sores
Cold sores, which are also called fever blisters, are groups of fluid-filled blisters that often erupt around the lips and sometimes under the nose or around the chin. Cold sores are caused by the herpes simplex virus type 1 and are very contagious. The initial infection (primary herpes) may be confused with a cold or flu and can cause painful lesions to erupt throughout the mouth. Once a person is infected with primary herpes, the virus stays in the body and causes occasional attacks.
Cold sore blisters usually heal in a week by themselves. Over-the-counter topical anesthetics can provide some relief. Your dentist may prescribe antiviral drugs to reduce these kinds of viral infections.
Oral Thrush
Thrush (also called Candidiasis or moniliasis) is a fungal infection that occurs when the yeast Candida albicans reproduce in large numbers. It is common among denture wearers. Most often it occurs in people with weak immune systems—the very young, elderly or those debilitated by disease, such as diabetes or leukemia. In addition, people with dry mouth syndrome are susceptible to candidiasis. Candida may also flourish after antibiotic treatment, which can decrease normal bacteria in the mouth.
Controlling candidiasis means focusing on preventing or controlling the condition that causes the outbreak.
Good oral hygiene is essential. Clean your dentures to remove Candida and remove them at bedtime. If the cause is dry mouth saliva substitutes and prescription medications may be helpful when the underlying cause of dry mouth is incurable or unavoidable.
Leukoplakia
Leukoplakia are thick, whitish-color patches that form on the inside of the cheeks, gums or tongue, these patches are caused by excess cell growth and are common among tobacco users. They can result from irritations such as an ill-fitting denture or the habit of chewing on the inside of the cheek. Sometimes leukoplakia is associated with oral cancer. Your dentist may recommend a biopsy if the patch appears threatening.
Your dentist will examine the lesion and checks the biopsy results to help determine how to manage the disease. Treatment begins with removing the factors that contribute to the lesion: quitting tobacco or replacing ill-fitting dentures or bridges.
* Your dentist should examine any mouth sore that lasts a week or longer.
This article, along with additional links, can be found at: https://www.mouthhealthy.org/en/az-topics/m/mouth-sores