Conditions · Tooth decay
Tooth decay
How to prevent it — and treat early decay at home.
Tooth decay (the medical term is dental caries) is when a tooth is weakened by repeated sugar attacks and plaque acid. Caught early it can sometimes be halted or reversed; left untreated it can spread and destroy the tooth.
What is tooth decay?
Tooth decay is when a tooth becomes weakened by sugar attacks and plaque acid. The normal bacteria in your mouth eat some of the sugar in your diet and produce acid; the acid removes calcium from the enamel and dentine, softening these weakened areas until they can crumble into a cavity.
Why does it matter?
Left untreated, decay spreads within a tooth and weakens the enamel and dentine until the tooth crumbles. It can affect chewing, the look of your smile and the way you speak, and cause bad breath, sensitivity and — in some cases — severe pain and infection needing urgent treatment.
How do you know if you have it?
Tooth decay often shows as a black, grey, brown or white mark, or a hole in a tooth. Sometimes it is sensitive or painful; sometimes it is not felt at all and is only found by a dentist during an examination.
How to prevent tooth decay
Every time you eat or drink something sugary, the bacteria in your mouth produce plaque acid that weakens your teeth for around 20 minutes. The more sugar attacks each day, the longer your teeth are under attack. So:
- Keep sugary snacks and drinks to mealtimes, not between them — and finish a treat in one sitting rather than grazing.
- Brush twice daily with a fluoride toothpaste, using a good technique; consider an electric toothbrush.
- Clean between your teeth daily with floss and/or interdental brushes.
- See your dentist for a check-up every 3–24 months, as they direct.
An oscillating-rotating brush such as the Oral-B Pro 1 (around £26) is rechargeable, has a two-minute timer and a pressure sensor that warns if you press too hard — and heads can be shared across the family. See it on Amazon.
Can tooth decay be reversed?
Early decay that has not yet crumbled into a cavity can sometimes be halted or even reversed with diet changes plus fluoride toothpaste and mouthwash — always directed by your dentist after an examination and usually some X-rays. Alongside the prevention advice above, your dentist may prescribe a high-fluoride toothpaste, suggest a fluoride mouthwash at a separate time to brushing, or apply a concentrated fluoride varnish, then monitor the area closely (often after 3–6 months).
When does decay need a filling?
Your dentist will advise if decay needs a filling or other restoration — usually when there is a cavity you cannot keep clean, when an X-ray shows the decay has spread past a threshold, or if you have sensitivity or pain. Your diet, how often you attend, your level of oral hygiene and how closely you follow advice all influence the decision.
Text and further advice adapted from dentalchoices.org.
Watch
See how decay starts — and stops
A short film on how sugar and plaque acid weaken a tooth, and the simple habits that keep decay away.
Common questions
Tooth decay — your questions answered
What causes tooth decay?
Plaque bacteria feeding on sugar in your diet and producing acid, which dissolves calcium from the enamel and dentine.
How do I know if I have tooth decay?
It may show as a dark or white mark or a hole, and can be sensitive — but often there are no symptoms and only a dentist finds it.
Can early decay be reversed?
Yes — decay that hasn’t yet formed a cavity can sometimes be halted or reversed with diet changes and extra fluoride, guided by your dentist.
How do I prevent decay?
Limit sugar to mealtimes, brush twice daily with fluoride toothpaste, clean between your teeth, and keep up regular check-ups.
When is a filling needed?
When there’s a cavity you can’t keep clean, the decay has spread on an X-ray, or you have sensitivity or pain.
Stop decay before it starts
The best defence is fewer sugar attacks and good daily cleaning.