The rule, stated first because it is the point
Any ulcer, sore area, lump, or red or white patch inside the mouth that has not resolved after about two weeks should be examined by a dentist or a doctor. Not monitored for another month, not treated with something from a pharmacy shelf, not searched for online. Examined.
That’s not because most such things are serious. The overwhelming majority are not. It’s because the small number that are serious behave in exactly this way — persisting quietly, often without much pain — and because the difference in outcome between finding something early and finding it late is substantial.
I would rather see twenty harmless things than miss one, and no dentist I know feels differently about being consulted over something that turns out to be nothing.
What ordinary mouth ulcers do
Common recurrent mouth ulcers are small, round or oval, with a pale center and a red rim, usually on the softer moving tissues — the inside of the lip or cheek, the side of the tongue, the floor of the mouth. They are painful out of all proportion to their size, and they typically heal within seven to fourteen days without leaving a mark.
Triggers vary between people and are often not identifiable. Minor trauma from a sharp tooth or an appliance, stress, hormonal cycles, certain foods and some nutritional deficiencies are all reported, and for many people they simply come and go. Frequent, unusually large, or unusually prolonged ulcers can occasionally point to an underlying condition, which is another reason for a proper assessment rather than a self-managed cycle.
A single ulcer that appears at the same spot repeatedly, particularly next to a rough edge, is often being caused by the edge. That is a fixable problem, and it is a good example of why someone looking is worth more than someone guessing.
The features that warrant prompt attention
Beyond the two-week duration, there are characteristics dentists are trained to notice: an ulcer with a raised, rolled or hardened edge; a lump that feels firm rather than soft; a patch that can’t be wiped away; an area that bleeds without provocation; numbness or altered sensation; difficulty swallowing or moving the tongue; a swelling in the neck; a tooth that becomes loose with no obvious dental explanation.
None of those descriptions is a diagnosis, and none of them should be used to reassure yourself either. They are the reasons to be seen quickly rather than eventually.
Risk factors that make prompt assessment more important include tobacco in any form, including smokeless products and paan, significant alcohol intake, and previous cancer of the head and neck. Where those apply, I would not wait two weeks.
What the soft tissue examination involves
At a routine check-up, a dentist is not only looking at teeth. A conventional soft tissue examination covers the lips, the inside of the cheeks, the tongue including its sides and underside, the floor of the mouth, the palate and the throat, and usually feeling the neck and under the jaw. It takes a couple of minutes and most patients barely register it happening.
Asking to have your tongue held in gauze and moved to the side is part of this rather than an oddity. The sides and undersurface of the tongue and the floor of the mouth are areas that need to be seen directly, and they are not visible in a bathroom mirror.
This is one of the strongest arguments for regular attendance even when nothing hurts, and one of the least discussed. A check-up is a screening appointment as much as a dental one.
What not to do while you wait
Do not apply strong household substances to a sore area. Undiluted preparations held against the lining of the mouth can cause a chemical burn, which converts a small problem into a larger and more painful one, and it complicates the examination when you do attend.
Do not assume that pain is the guide. Serious conditions in the mouth are frequently painless in their early stages, while a minor ulcer can be agonizing. Duration and appearance are far more informative than how much it hurts.
And don’t let embarrassment about the cause delay you. Dentists see the results of tobacco, of alcohol, of long gaps in attendance, and none of it changes how a persistent lesion is handled. Two weeks is the rule, and everything else in this article is context around it.
Common questions
I bite my cheek regularly and it ulcerates. Is that a concern?
Repeated trauma at the same spot has a cause worth finding, whether that is a sharp edge, the way the teeth meet, or a habit. It is also a situation where persistent irritation should not simply be tolerated, so mention it rather than living with it.
Are mouth ulcers ever contagious?
Common recurrent ulcers are not. Some other conditions that produce blisters or sores in the mouth are caused by viruses and can be transmissible. Distinguishing them is a clinical matter, which is a further reason not to self-diagnose from pictures.
What if it heals just before my appointment?
Go anyway and describe it. Something that appears and resolves repeatedly at the same site is useful information, and a photograph taken while it was present can be genuinely helpful to the person examining you.
Dental Surgeon, Dr. Shruti Goel
Dr. Shruti Goel is a dental surgeon in practice since 2006 — around 20 years of clinical work — at Advanced Dental Clinic in Faridabad. She writes here about hygiene and prevention: the part of dentistry that happens at home, between appointments, and that decides how much of the rest is ever needed.