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Decay and erosion are different processes and get confused constantly.
Decay needs bacteria: they consume sugar and produce acid in the plaque sitting on the tooth. Erosion needs no bacteria at all. Acid in the mouth dissolves enamel directly, across whole surfaces rather than in one spot.
Which is why sugar-free fizzy drinks still erode teeth. They just do not cause cavities.
What it looks like
Erosion is diffuse, which is what distinguishes it from decay:
- Teeth looking more yellow, as thinned enamel lets dentine show through
- Front teeth becoming see-through at the edges
- Biting surfaces developing shallow dished hollows, often with a filling standing proud of the surrounding tooth
- Edges chipping
- Generalised sensitivity to cold
- A smooth, glazed appearance rather than a chalky one
That raised filling is the single most reliable sign. The filling has not grown; the tooth around it has dissolved.
The usual sources
| Source | Why it matters |
|---|---|
| Fizzy drinks, including the diet versions, and flavoured sparkling waters | Carbonic, phosphoric and citric acid; the diet versions erode as readily. Plain, unflavoured sparkling water is a different matter: UK guidance puts it with still water, milk and tea in the least erosive group |
| Fruit juice and smoothies | Highly acidic even with no added sugar |
| Citrus fruit, especially sucked or held | Direct and prolonged contact |
| Sports and energy drinks | Acidic, and typically sipped over a long session |
| Wine, especially white | Acidic, and often drunk slowly |
| Vinegar-based foods | Frequent exposure adds up |
| Reflux, vomiting, morning sickness | Stomach acid is far stronger than anything you drink |
Why sipping is the real culprit
Saliva neutralises acid and puts minerals back, but it takes twenty minutes to an hour to finish. One drink is one exposure. The same drink nursed over two hours keeps the mouth acidic the entire time, and the repair never completes.
The pattern matters more than the quantity. A can of fizzy drink with lunch is far less damaging than the same can sipped across an afternoon.
What to do
- Drink acidic things with meals, and finish them reasonably promptly
- Use a straw for fizzy drinks, positioned past the front teeth
- Finish with water, or something neutral — milk or cheese are genuinely good
- Rinse with plain water, immediately. Waiting a while before brushing is often suggested, on the grounds that softened enamel brushes away more easily. The evidence for it is weak, and UK guidance does not treat the timing of brushing as important. If waiting would mean skipping your night brush, brush — that part is well established
- Use a fluoride toothpaste, and do not rinse after brushing
- Choose a non-abrasive toothpaste — whitening pastes are often the wrong choice here
If stomach acid is involved
Reflux, frequent vomiting and morning sickness cause the most severe erosion, because stomach acid is far stronger than dietary acid. The pattern is distinctive: worst on the inside surfaces of the upper front teeth, where you cannot see it.
Rinse with water, or with a little bicarbonate of soda dissolved in water, and do not brush immediately. The underlying cause is worth treating medically — and it is worth telling your dentist, because the wear pattern is often how it gets spotted.
Decay is about what you eat. Erosion is about how long it stays in your mouth.
