Dental erosion: wear without friction

What is dental erosion?

An acid needs no movement to act. Wherever it stays in contact with the tooth, it gradually dissolves the minerals in the enamel, over the whole surface it reaches, and not only where two teeth meet. This is what gives erosion its appearance: a diffuse, even loss that progresses without any telltale movement.

It has nothing to do with decay. In decay, the acid is produced on the spot by plaque bacteria, from sugars; it creates a cavity in one specific place. In erosion, the acid comes from the diet or from the stomach, without bacteria, and it attacks clean surfaces. The two can coexist in the same person, but they are not prevented in the same way.

In the mouth, erosion rarely works alone. The acid softens the surface layer of the enamel; the tongue, the opposing teeth or the toothbrush then remove this weakened layer. It is this combination that specialists call erosive tooth wear, and it is what is seen at the examination.

How can you recognise it?

By teeth that look smooth and shiny, as if polished, without the fine lines found on intact enamel. Often, a narrow band of enamel is preserved right along the gum line, protected by plaque or by the fluid from the gum, and the eroded surface begins just beyond it. On the front teeth, the edges become thin, slightly translucent, sometimes chipped. On the molars, small cup-shaped hollows form at the tips of the cusps, and old fillings or composite restorations seem to stand above the surface, because the tooth around them has dissolved away.

The teeth may turn more yellow, because the darker dentine shows through the thinned enamel, and they may become sensitive to cold or to acid. Wear on the inner surfaces of the upper teeth, the ones the tongue touches, points to a cause coming from the stomach.

These signs become visible late. At first, nothing hurts and nothing is noticeable; it is the examination that picks them up, and grades them with a simple score, area by area, so that changes can be followed over time.

Where do the acids come from?

From the diet, first of all: fizzy drinks and energy drinks, fruit juices, citrus fruit, wine, cider, vinegar and vinaigrettes, some sour sweets, as well as certain medicines and supplements, such as effervescent tablets or chewable vitamin C. What makes a drink erosive is its acidity and its ability to stay acidic in the mouth; the calcium it contains, by contrast, reduces its effect. Whole fruit matters mainly when it is nibbled over a long time.

From the stomach, next. Gastro-oesophageal reflux brings acid up into the mouth, often at night, sometimes without any heartburn being felt. People with reflux are two to four times more likely to have erosive tooth wear, and around one adult in three with erosion has reflux. Repeated vomiting, whatever the cause, acts in the same way. When a cause of this kind is suspected, assessing it is not a matter for the dental examination alone, and a doctor’s opinion is part of the management.

Less often, the acid comes from work, when acidic fumes are breathed in or acidic liquids are handled.

Why does frequency matter more than quantity?

Because what causes wear is the length of time the surface stays acidic. The same amount taken in one go, with a meal, or spread out over the day does not put the enamel in the same situation. A study that compared 300 people with erosion with 300 people without it put figures on this: having acidic food or drink between meals, sipping a drink, holding it in the mouth or nibbling fruit over a long time multiplied the risk by around ten. Three acidic intakes a day did the same. Fruit eaten with a meal, on the other hand, was not associated with the risk.

The rule that follows is simple: less often, more quickly, with meals rather than between them. An acidic drink finished in a few minutes exposes the teeth less than a bottle nursed all afternoon.

What saliva does, and what it does not do

The mouth does not passively take whatever it receives. Saliva dilutes the acid, clears it away through swallowing, neutralises it thanks to its buffering capacity, then redeposits calcium and phosphate on the enamel: a softened surface can in this way partly harden again. It is the most important biological factor in protection, and it explains why two people exposed to the same acids do not wear at the same rate.

It does not rebuild what has been lost. Once the layer has been worn away, the tooth does not grow back. And its protection diminishes when there is too little of it: a dry mouth caused by certain medicines, dehydration, intense sport. Drinking water and chewing sugar-free gum after an acidic intake help saliva do its job.

Should you wait before brushing your teeth?

It is common advice, and it deserves some qualification. It comes from laboratory studies in the 2000s, in which enamel that had just been softened by acid wore away more under a toothbrush. Clinical data do not confirm it: in the European survey that examined more than 3,000 young adults, waiting after breakfast was not associated with less wear, and in the case-control study mentioned above, brushing within ten minutes of having something acidic was not associated with any change in risk. A 2024 review concludes that brushing with a fluoride toothpaste straight after an acidic intake does not increase wear.

Waiting does no harm, but it is no substitute for anything. What protects is a fluoride toothpaste, a soft brush and light pressure. Toothpastes containing stannous fluoride protect enamel better against acids in short-term studies, with one reservation: independent studies give more mixed results than the manufacturer’s.

How can the damage be limited?

By first identifying the source, because no toothpaste can make up for repeated acid exposure. The questions asked at the examination help with this: what you drink, when and how; heartburn or acid coming back up; medication; sport. Then by acting on what can be changed: spacing out acidic intakes, keeping them to mealtimes, no longer sipping, rinsing with water afterwards, treating reflux with your doctor.

Restorations come afterwards, and only if the wear is causing problems: sensitivity, appearance, function. Restoring a tooth that is still being exposed to acid is like repairing a roof in the rain.

When does it need treating?

The score recorded at the examination guides the decision. In each of the six areas of the mouth, the most affected surface is scored from 0 to 3; the total points to the course of action: monitoring and a check-up some time later when it is low, advice and follow-up with photographs when it is moderate, reinforced prevention and, if the wear is still progressing, restorations when it is high. This score, the BEWE (Basic Erosive Wear Examination), is the one recommended by the European consensus.

Working out the respective roles of erosion, grinding and brushing is a matter for the clinical examination: the page on tooth wear describes how this is done. And if you have noticed something without knowing what to make of it, the article “Worn teeth: what should you do first?” explains what to look out for while you wait for your appointment.