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While the exact cause of aphthous stomatitis is unknown, there are a few possible causes, including stress, insufficient sleep, gastrointestinal problems, nutritional deficiency, local trauma, and sodium lauryl sulfate. There is no well-established cure for aphthous stomatitis, but a healthy lifestyle, ample sleep, regular exercise, a good diet, and proper dental hygiene are the best and most proven approaches to manage the condition.
Aphthous stomatitis (commonly called canker sores) is a dental condition wherein there is the recurring formation of small shallow lesions (or simply mouth ulcers) inside your mouth or on your lips.
The term is imported from the Greek word aphtha, meaning mouth, and stomatitis, meaning inflammation of mucous membranes. Although mouth ulcers are painful, they are mostly non-contagious and cure themselves within a week or two. Many studies have been carried out by doctors, dentists and other qualified professionals to identify a causative organism behind the formation of canker sores, but aphthous stomatitis appears to be benign, non-infectious, and not sexually transmittable. Interestingly, despite aphthous stomatitis patients being found around the world, this condition is more common in developed countries, especially the US.

Before we delve any deeper, let’s look at a few interesting statistics of aphthous stomatitis that I have compiled from various reports and publications in the dental domain:
- More than 60% of people will develop a mouth ulcer at least once in their lifetime.
- Around 20% of people will get recurring mouth ulcers (aphthous stomatitis).
- Over 80% of people with aphthous stomatitis first developed the condition before the age of 30.
- More than 40% of people with aphthous stomatitis have a family history of canker sores.
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Types Of Aphthous Stomatitis
Based on the latest studies in this domain, the dental condition of recurring mouth ulcers can be classified into three types:
1. MiAU
Minor aphthous ulceration (MiAU) is the most common type of aphthous stomatitis, accounting for 80-85% of all cases. Some dental experts prefer to call this minor recurrent aphthous stomatitis (MiRAS). The lesions of this subtype of aphthous stomatitis are referred to as minor aphthae. These lesions are ovular in shape, with the diameter being less than 10 mm (usually about 2–3 mm). This type of canker sore takes around seven to ten days for recovery, and the good thing is, they don’t leave any scarring behind!
2. MaAU
Major aphthous ulcers (MaAU) are a slightly more serious type of aphthous stomatitis. They account for roughly 10% of ulceration cases. Although similar to MiAU, the size of the lesion is often more than 10mm and ulceration is typically deeper. These larger, deeper lesions take longer to heal (around 20-30 days). They are not in a well-rounded (or ovular) shape and have irregular borders. Moreover, they are notorious for leaving some signs of the past in the form of a scar.
3. Herpetiform Ulcers
This is the rarest breed of aphthous stomatitis, and is also called stomatitis herpetiformis, because the lesions resemble a primary infection caused by the herpes simplex virus. Fortunately, herpetiform ulceration is not caused by malevolent herpes viruses. Although in singularity they are the smallest of the three forms, measuring less than 1mm in diameter, over time, multiple lesions develop within that small vicinity and they collude to form apparently large ulcers. Healing takes a minimum of two weeks, but they don’t leave any ugly scars like MaAU. This type of ulceration usually affects elderly people.
Also Read: What Is Odynophagia (Pain When Swallowing Food)?
Causes Of Aphthous Stomatitis
While there is no well-established study corroborating the actual cause of these excruciating ulcers, I have compiled a list of a few probable causes of aphthous stomatitis:
- Stress: This is observed to be the most common reason for recurring mouth ulcers in numerous studies. As aphthous stomatitis typically affects teenagers and young adults, you’ll often find students developing painful ulcers during exam time.
- Insufficient sleep: This is another contributor to ulceration. The less you sleep, the more likely you are to get canker sores.
- Gastrointestinal problems: People suffering from constipation, acidity or other digestion-related problems often complain about the recurring formation of tormenting ulcers.
- Nutritional deficiency: Regularly eating fast food and avoiding green leafy vegetable can cause a deficiency of vitamin B, iron and folic acid, which in turn expedites the likelihood of ulceration.
- Local trauma: A minor injury from customary dental work, overzealous toothbrushing, or an accidental bite of food with sharp edges may lead to the development of canker sores.
- Sodium lauryl sulfate: Sodium lauryl sulphate (SLS) is a chemical that is present in some brands of toothpaste and other oral health care products. SLS is known to be the culprit of aphthous stomatitis for many sufferers.
- Other allergens: Sometimes, recurring canker sores may be a manifestation of an allergic reaction due to the intake of certain foods items, such as chocolate, strawberries, cheese, eggs, coffee, nuts, tomatoes, and other highly acidic foods.
Strange as this may seem, the occurrence of aphthous stomatitis is rare in people who smoke. In fact, quitting smoking can precede the onset of aphthous stomatitis in people who are otherwise unaffected by canker sores. Some studies have also reported that quitting cigarette smoking suddenly can exacerbate the condition in those who were already suffering from aphthous ulceration.
Also Read: Why Don’t Cuts And Wounds Inside The Mouth Get Infected By Bacteria?
Treatment For Aphthous Stomatitis
Although you might be very interested in learning the permanent cure for this dental illness, unfortunately, there is none. That may sound a little harsh, but presently, there is no well-established cure for aphthous stomatitis. Treatments that dietitians/dentists/other medical experts suggest simply ameliorate your pain, improve healing time or at the most reduce the frequency of ulceration occurrence. In a capitalistic society with a booming pharmaceutical industry, you can easily find hundreds of over-the-counter medicines for mouth ulcers, often in the form of topical gels/creams. However, no scientific studies state that they actually help in “curing” aphthous stomatitis. A healthy lifestyle, ample sleep, regular exercise, a good diet, and proper dental hygiene are the best and most proven approaches to manage/conquer aphthous stomatitis.
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References (click to expand)
- Preeti, L., Magesh, K., Rajkumar, K., & Karthik, R. (2011). Recurrent aphthous stomatitis. Journal of Oral and Maxillofacial Pathology. Medknow.
- C Scully. Oral and Maxillofacial Medicine - ScienceDirect.com. ScienceDirect
- Bruch J. M.,& Treister N. (2016). Clinical Oral Medicine and Pathology. Springer International Publishing