Tooth Decay

Overview

Tooth decay is damage to a tooth's hard outer layer, called enamel. It happens when bacteria in the mouth turn sugars from food and drink into acid. This acid slowly eats away at the tooth, creating small holes called cavities. If left untreated, decay can cause pain, infection, and even tooth loss.

Yes, tooth decay is very common. Most adults have had at least one cavity at some point in their lives. It is one of the most widespread health conditions globally.

Tooth decay affects people of all ages. Children and teenagers are especially prone because their teeth are still developing. Older adults can also get decay around old fillings, crowns, or exposed tooth roots. People who eat a lot of sugary foods or do not brush regularly are more likely to develop cavities.

Symptoms

Common symptoms

• Toothache or a sharp pain in a tooth
• Sensitivity to sweet, hot, or cold foods and drinks
• Visible holes, pits, or dark spots on the teeth
• White, brown, or black stains on a tooth surface
• Pain when biting down

Symptoms in children

• Baby teeth can decay, especially if a child falls asleep with a bottle containing sugary liquids.
• A child may complain of tooth pain or avoid eating certain foods.
• You might see white spots, brown patches, or holes on their teeth.

Symptoms in older adults

• Decay often happens around old fillings or under crowns.
• Receding gums can expose tooth roots, which decay more easily.
• Dry mouth caused by some medicines can make decay more likely.

Causes

Main causes

• Bacteria in the mouth form a sticky film called plaque on your teeth.
• Plaque turns sugars from food and drink into acid.
• This acid attacks the enamel, the hard protective outer layer of the tooth.
• Over time, repeated acid attacks wear down the enamel and create cavities.

Risk factors

• Eating or drinking lots of sugary or acidic foods and drinks, such as candy, soda, and fruit juice
• Not brushing your teeth twice a day with fluoride toothpaste
• Not cleaning between your teeth with floss or an interdental brush
• Having a dry mouth, because saliva helps wash away food and acid
• Taking certain medicines or having health conditions that reduce saliva
• Skipping regular dental check-ups

When to see a doctor

See a doctor urgently if:

• Tooth pain that interferes with daily life or sleep
• Signs of infection, such as swelling in the face or gums, pus, or a fever
• A tooth that is chipped, cracked, loose, or knocked out

Book a routine appointment if:

• See a dentist regularly for check-ups and professional cleanings.
• If you notice any stains, holes, or lasting sensitivity, make an appointment.
• Children should see a dentist from an early age, usually by their first birthday.

Diagnosis

A dentist checks your teeth visually and may use a small tool to feel for soft spots. They will also ask about any pain, your eating habits, and how well you care for your teeth.

Tests that may be done

• Visual inspection of every tooth surface
• Dental X-rays to see decay between teeth or under fillings
• Sometimes a special light or dye to spot early decay that is hard to see

What to expect at your appointment

The dentist will gently examine your mouth and teeth. If they find decay, they will explain what they see and discuss treatment options. The visit is usually painless, and you can ask questions at any point.

Treatment

Treatment depends on how deep the decay has gone. Early decay can sometimes be stopped or reversed with fluoride. If a cavity has formed, the dentist will remove the decayed part and fill the tooth. More severe decay may need a crown, root canal treatment, or in rare cases, the tooth may need to be removed.

Self-care at home

• Brush your teeth twice a day with fluoride toothpaste.
• Clean between your teeth with floss or an interdental brush every day.
• Cut back on sugary and sticky foods and drinks, especially between meals.
• Rinse your mouth with water after eating if you cannot brush.
• If your dentist recommends a fluoride mouthwash, use it as directed.

Medical treatments

A dentist can apply fluoride varnish or gel to help repair very early decay. For cavities, the decayed part is removed and a filling is placed. If the decay reaches the inner pulp, a root canal treatment removes the infected nerve and tissue to save the tooth. In serious cases, the tooth may need a crown or extraction. Your dentist will talk you through the most suitable treatment. Pain relief can help during and after procedures, but always ask your dentist or pharmacist for advice on what to use.

When is surgery considered?

In advanced cases, a minor operation may be needed to remove an infected tooth or drain an abscess. This is usually done by a dentist or an oral surgeon under local anaesthetic.

Living with this condition

Keep brushing and flossing your teeth every day, even after treatment. If you have a filling, crown, or bridge, clean around it carefully. Go to your regular dental check-ups so any new decay can be caught early.

Lifestyle tips

• Limit sugary snacks and drinks to mealtimes rather than having them throughout the day.
• Chew sugar-free gum after meals to help your mouth produce more saliva.
• Drink plain water instead of sugary or acidic drinks.
• If you smoke, consider quitting. Smoking weakens your gums and increases the risk of decay and gum disease.

Diet and exercise

A balanced diet with plenty of fruits, vegetables, whole grains, and dairy products helps keep your teeth and gums strong. Drink water that contains fluoride if it is available in your area. Avoid sticky, sugary foods like candy, dried fruit, and chewy sweets between meals.

Mental health and emotional wellbeing

Dental problems can affect how you feel about your smile and can make you feel self-conscious. Tooth pain can also disrupt sleep and mood. It is completely normal to feel anxious or worried. Talking to your dentist about your concerns can make a big difference, and dental teams are trained to help nervous patients feel comfortable.

Prevention

Yes, most tooth decay can be prevented. Good oral hygiene, a low-sugar diet, regular dental check-ups, and using fluoride toothpaste all help protect your teeth. Drinking fluoridated water where available also strengthens enamel and helps prevent decay.

Screening programmes

Regular dental check-ups act as a screening tool for tooth decay. Dentists can spot early signs of decay before it becomes painful or serious. The NHS recommends seeing a dentist regularly, even if you have no symptoms. Your dentist will tell you how often you should come back.

Complications

If left untreated

• Severe, persistent toothache
• Infection that spreads to the jaw, face, or other parts of the body
• Abscess, a painful pocket of pus, which may cause swelling and fever
• Tooth loss
• Difficulty eating or speaking properly

Long-term outlook

Tooth decay is one of the most treatable health conditions. With early care, most people can keep their natural teeth and avoid serious problems. Even if decay is advanced, modern dental treatments can relieve pain, repair damage, and restore a healthy smile.

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