Tooth decay
- Dr Gurmandeep Sond, former Clinical Development Manager at Bupa Dental Care
- Michelle Harrison, Freelance Health Editor
Tooth decay is when the surface of your tooth starts to wear away, sometimes causing a painful hole to form. It’s usually caused by eating sugary foods or not cleaning your teeth properly. Regular check-ups with your dentist can help find tooth decay early and stop it getting worse.
About tooth decay
When you eat food and drinks that contain sugar or starch, the bacteria that live in your mouth feed on them and make acids. The acids mix with the bacteria, food, and saliva in your mouth to create a sticky film that coats your teeth. This is known as plaque. If you don’t clean away the plaque properly, the acids in it start to erode the enamel (hard outer layer of your teeth). This creates tiny holes called cavities.
If tooth decay is found early, treatment can stop it from getting worse or even reverse the damage. But without treatment, the hole (cavity) can get bigger. This allows bacteria to enter the sensitive layers inside your tooth and cause pain. Eventually, you may need to have a filling, root canal treatment, or your tooth removed completely. So, the sooner you can see a dentist for tooth decay, the better.
What causes tooth decay?
Tooth decay happens when the acids in plaque start to build up and dissolve the surface of your tooth (enamel). This is more likely to happen if you:
- eat lots of sugary food and drinks
- don’t clean your teeth and gums properly
- snack in between meals, because your teeth don’t have time to recover from acid attacks
- have a condition called dry mouth, where you don’t produce enough saliva
- don’t get enough fluoride (a mineral that prevents cavities)
- have a dental problem that causes plaque to build up – for example, a broken filling
Symptoms of tooth decay
In the early stages, tooth decay might not cause any symptoms. But as it gets worse, you might have:
- toothache, which could be a dull ache or a sharp pain
- sensitive teeth, especially when you eat something hot, cold or sweet
If you can see it, tooth decay might look like:
- a small hole (cavity)
- white, brown or black spots on your teeth
If your tooth decay has developed into a tooth infection, you might also notice:
- swelling around your teeth or gums
- a bad taste or smell in your mouth
Diagnosis of tooth decay
If you have tooth pain, make an appointment to see a dentist as soon as possible. They’ll be able to see if you have tooth decay and recommend the best treatment for you. Your dentist will thoroughly examine your mouth and ask about your symptoms. They’ll likely put a bit of pressure on your teeth using dental instruments to see which ones are sensitive. They might also do a dental X-ray of your mouth, to check for any hidden cavities inside your teeth.
How to treat tooth decay
The type of tooth decay treatment you’ll need will depend on how advanced the decay is. Your dentist might recommend the following types of cavity treatment.
Fluoride treatments
If your tooth decay is still in the early stages, you dentist might recommend treating it with products that contain fluoride. Fluoride is a mineral that helps to repair the enamel on your teeth. It’s found in many toothpastes, mouthwashes and tap water. Fluoride can stop tooth decay from getting any worse, and sometimes even reverse it.
Your dentist might prescribe fluoride treatments for you to use at home. Or they might apply a stronger fluoride varnish, gel or paste to your teeth.
Fillings
If you have a hole (cavity) in your tooth, a filling might be the best treatment option. This is when your dentist removes the decay from inside your tooth, then fills the cavity with a composite resin or an amalgam. They then shape and polish the filling to match the natural shape of your tooth and harden it using a special light. It’s usually done under local anaesthesia to numb the area and you can go home the same day.
Dental crowns
If your tooth decay is too badly damaged for a filling, your dentist might suggest covering your tooth completely with a dental crown. This is an artificial cap the fits over your damaged tooth and looks like your other teeth. Your dentist will remove the decayed and damaged part of your tooth and fit a temporary crown while a custom-made one is prepared at a laboratory. Once this is ready, your dentist will remove your temporary crown and cement the permanent one in place.
Root canal treatment
If your tooth cavity has spread all the way to the root inside your tooth, you may need a root canal treatment. This aims to try and save badly damaged, infected or rotten teeth. Your dentist will numb the area and make a hole in the top of your tooth. They will then clean out the bacteria from inside your tooth and put in a temporary filling. You’ll have a second appointment to make sure all the bacteria are gone before putting in a permanent filling or a crown.
Tooth removal
If your tooth decay is severe, and your tooth can’t be repaired, your dentist will recommend removing it completely. To do this, they’ll numb the area using a local anaesthetic, gently loosen your tooth from its socket and carefully take it out. Sometimes they might need to put a small stitch in your gum to help it heal. If your dentist removes your tooth, they will also discuss your options for replacing it with an artificial one at a later date.
How to prevent tooth decay
The best way to avoid tooth decay is to take good care of your teeth and gums. Here are some tips.
- See your dentist and hygienist regularly for check-ups and cleaning. They’ll be able to spot signs of tooth decay early.
- Brush your teeth twice a day using a fluoride toothpaste.
- Spit instead of rinsing when you brush, to avoid washing away the fluoride in your toothpaste.
- Clean in between your teeth once a day, using floss or an interdental brush.
- Use a mouthwash that contains fluoride.
- Avoid eating lots of sugary food and drinks, and try to avoid snacking between meals.
- Drink tap water, because it’s fortified with fluoride.
- Chew sugar-free gum for 20 minutes after eating. It helps your mouth to make saliva, which washes away food particles and neutralises acids.
Other helpful websites
This information was published by Bupa's Dental Content Team and is based on reputable sources of medical evidence. It has been reviewed by appropriate medical or clinical professionals and deemed accurate on the date of review. Photos are only for illustrative purposes and do not reflect every presentation of a condition.
Any information about a treatment or procedure is generic, and does not necessarily describe that treatment or procedure as delivered by Bupa or its associated providers.
The information contained on this page and in any third party websites referred to on this page is not intended nor implied to be a substitute for professional medical advice nor is it intended to be for medical diagnosis or treatment. Third party websites are not owned or controlled by Bupa and any individual may be able to access and post messages on them. Bupa is not responsible for the content or availability of these third party websites. We do not accept advertising on this page.
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- Delivering better oral health: an evidence-based toolkit for prevention. Department of Health and Social Care. gov.uk, last updated November 2021
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