Aphthae and Canker Sores: What They Are, Why They Come Back and What Helps

A single small ulcer on the inside of your lip can make eating, drinking and even talking unpleasant for a week. In the United States these lesions are usually called canker sores. In German-speaking Europe and in most medical literature the same lesions are called aphthae — and that is exactly why so many people end up searching for a translation. The two words describe one and the same thing.

This page explains what an aphtha actually is, how the three clinical forms differ, what triggers them, how long they take to heal and where the line runs between a harmless recurring nuisance and a finding that needs a professional examination.

What are the three types of aphthae?

Classifying the lesion is the first thing a clinician does, because the type determines both the expected healing time and how aggressively it should be treated.

Minor aphthae account for roughly 80 percent of all cases. They are shallow, heal on their own and leave no trace. Most people who say they get canker sores mean this form.

Major aphthae — also called Sutton's disease — are deeper, considerably more painful and can interfere with swallowing when they sit far back. Because the ulceration reaches into deeper tissue, they can heal with a visible scar. Major aphthae that persist beyond three weeks always warrant an examination, since a long-standing solitary ulcer needs to be distinguished from other causes.

Herpetiform aphthae are the rarest form and the most misleadingly named. The name only refers to the grouped, herpes-like appearance — there is no herpes virus involved. Dozens of pinpoint ulcers appear at once and can merge into larger irregular areas. This form tends to start later in life and recurs more frequently than the others.

How long does a canker sore last?

A minor aphtha follows a predictable course. One to two days of burning or tingling before anything is visible, then a red spot, then the open ulcer with its white center, which is the most painful stage and lasts three to five days. Pain then subsides noticeably even though the lesion is still visible, and the mucosa closes over within seven to fourteen days from the start.

Major aphthae take two to six weeks. Herpetiform crops resolve in one to two weeks, but new crops may follow quickly enough that the mouth never feels entirely clear.

Nothing available over the counter shortens these timelines dramatically. The realistic goal of treatment is pain control and protecting the ulcer from further irritation while the mucosa does the healing itself.

Aphthae, dentures and dental implants

Anything with an edge that rubs the mucosa can seed an aphtha, which makes prosthetic dentistry directly relevant. A denture whose border presses into the vestibule, a crown with a rough margin, a clasp that has bent over the years or a brand-new appliance in its first weeks are all classic mechanical triggers. When lesions keep appearing in the same spot, the answer is almost never a stronger gel — it is finding and smoothing whatever is touching that spot.

This is also one of the underappreciated arguments for a fixed, implant-supported restoration. A removable denture rests on the mucosa and moves against it every time you chew; an implant-supported restoration transfers the load into the jawbone and leaves the soft tissue largely alone. Patients who switch from a loose lower denture to a titanium implant-retained restoration frequently report that their recurring sore spots simply stop.

A word on timing: if you have an open lesion, minor oral procedures are usually still possible, but elective surgery in that area is better postponed until the mucosa has closed. Tell the practice about a history of frequent aphthae before treatment — retraction, matrix bands and suction tips all cause exactly the kind of micro-trauma that sets off a new lesion, and the team can work more gently if they know.

Frequently asked questions

What is the English word for Aphthen?

Canker sore in American English, aphthous ulcer or aphtha in clinical English. German Aphthe corresponds to the singular aphtha, German Aphthen to the plural aphthae. The condition of repeated outbreaks is called recurrent aphthous stomatitis.

Are canker sores contagious?

No. Aphthae are not caused by a transmissible pathogen, so you cannot pass them to anyone by kissing, sharing utensils or drinking from the same glass. Cold sores, which are caused by herpes simplex virus, are contagious — which is the main reason the two are confused.

What is the difference between a canker sore and a cold sore?

Location and appearance. A canker sore is a single shallow ulcer with a white center and red rim on the movable lining inside the mouth, and it is not contagious. A cold sore starts as a cluster of small blisters on or around the lips, crusts over, and is caused by a virus you can transmit.

What deficiency causes canker sores?

Iron, vitamin B12, folate and zinc deficiencies are all associated with more frequent recurrences. They are contributing factors rather than direct causes, and they explain only a minority of cases. A blood test makes sense when lesions are frequent; taking supplements without a confirmed deficiency has not been shown to help.

How do you get rid of a canker sore fast?

You cannot make the mucosa heal faster than its own timeline, but you can remove the pain and stop making it worse. A barrier paste or patch over the ulcer, a topical anesthetic before meals, avoiding acidic and spicy food, and switching to an SLS-free toothpaste with a soft brush is the combination that works. For large or very frequent lesions, a dentist can prescribe a topical corticosteroid or cauterize the ulcer in the office.

Can stress cause canker sores?

Yes, indirectly. Stress and sleep deprivation are among the most consistently reported triggers, and many people can predict an outbreak from their workload. Stress does not create the lesion by itself — it lowers the threshold at which other factors, particularly minor trauma, set one off.

What are major aphthae?

Aphthae larger than one centimeter, also known as Sutton's disease. They are deeper than the common minor form, take two to six weeks to heal, often occur on the soft palate or in the throat where they interfere with swallowing, and can leave a scar. Any large ulcer that lasts longer than three weeks should be examined.

What are herpetiform aphthae?

A rare form in which ten to a hundred pinpoint ulcers, each one to three millimeters across, appear in crops and may merge into larger irregular areas. Despite the name there is no herpes virus involved — the term describes only the clustered appearance. This form recurs more often than minor aphthae and usually starts in adulthood.

Medically reviewed: This article was reviewed for medical accuracy by the specialist network of Leading Implant Centers. It provides general information and does not replace an individual examination and diagnosis.