Tooth decay happens when acids damage the hard outer layers of a tooth.
Over time, this damage can lead to a hole, known as a cavity.

Tooth decay is sometimes called dental decay or dental caries. They all mean the same thing.

---

What causes tooth decay?

Tooth decay is caused by plaque acids.

Plaque is a sticky film of bacteria that forms on your teeth every day.
When you eat or drink foods that contain sugar, the bacteria in plaque produce acids.

These acids:

• Soften the tooth surface.
• Gradually dissolve the tooth structure.
• Can eventually create a cavity.

If decay is not treated, it can lead to pain, infection, or tooth loss.

---

What is a tooth made of?

Understanding the parts of a tooth helps explain how decay develops.

• Enamel: The hard outer layer of the tooth. It is the strongest substance in the body and does not feel pain.
• Dentine: The layer under the enamel. It is softer and contains tiny nerve endings, which is why decay here can cause sensitivity.
• Pulp: The soft centre of the tooth. It contains nerves and blood vessels.

---

Why do teeth decay?

Tooth decay happens when sugars react with bacteria in plaque.

This creates acid attacks that can last around an hour each time you eat or drink sugar.

Saliva helps repair early damage by neutralising these acids and hardening the enamel again.

Problems happen when sugar is eaten often, especially between meals.
This leaves teeth under constant acid attack, with little time to recover.

---

What are the signs of tooth decay?

Early tooth decay often has no symptoms.

When decay is still in the enamel:

• You may not feel anything at all.

As decay reaches the dentine:

• Teeth may become sensitive to hot, cold or sweet foods.

If decay reaches the pulp:

• Pain can become severe.
• Infection or an abscess may develop.
• The tooth may need more complex treatment or removal.

Regular dental visits help spot decay early, when it is easier to treat.

---

What treatment might I need?

Treatment depends on how advanced the decay is.

• Fillings: Used when decay is small or moderate.
• Root canal treatment: Needed if the nerve inside the tooth is infected or dying.
  The tooth can then be restored with a filling or a crown.
• Tooth removal: Sometimes necessary if the tooth is badly damaged.

---

How can I prevent tooth decay?

Good daily habits make a big difference.

Try to:

• Brush for two minutes last thing at night and at least once more during the day.
• Use fluoride toothpaste every time you brush.
• Clean between your teeth once a day using floss or interdental brushes.
• Lower how often you have sugary foods and drinks. Try to keep sugar to mealtimes.
• Visit your dental team regularly, as advised.

---

Need advice?

If you’re worried about tooth decay or have pain or sensitivity, speak to your dental team.
Early care can prevent small problems from becoming bigger ones.

---

People who viewed this page also visited...

• Dental x-rays

• Pit and fissure sealants

• Sugar-free gum