Tooth decay Dr Trisha Macnair The most common - and most preventable - problem affecting children's teeth is dental decay, or caries.

In this article

What is tooth decay? Symptoms

Causes and risk factors Treatment and recovery

Dental decay is a breakdown of the normal hard tissues on the outer surface of the teeth to form a soft cavity or hole. In severe decay, the cavity may be very deep, affecting the nerve and blood vessels in the central pulp.

At first, tooth decay may not cause any obvious symptoms, especially in milk teeth. But as it progresses it may cause toothache, or sensitivity to hot, cold or very sweet foods. If the nerve becomes affected, infection may establish and lead to an abscess, with severe pain, swelling of the jaw and fever.

Bacteria that thrive on the teeth cause tooth decay, particularly when there's a large amount of sugary food debris left in the mouth. The bacteria grow in a sticky coating on the teeth called plaque. They break down food sugars into acids that etch away at the surface enamel, leaking out the calcium and phosphate minerals to soften and destroy the enamel and dentine below.

Frequent consumption of sugary foods and drinks increases the risk of decay, especially if allowed to bathe the teeth for long periods (for example, if teeth aren't brushed regularly or if a baby sucks on a bottle full of sweet drink).

Dental decay is very common. The addition of fluoride to toothpaste has helped to protect teeth and cut decay, but the trend towards sweeter snack foods in children's diets is working against this.

Children should have check-ups at the dentist every six months so decay can be spotted early. If your child has toothache, get the advice of a dentist. They'll be able to spot decay by examining the teeth and may take an x-ray to investigate the extent of damage.

Very minor decay can sometimes remineralise on its own, if the plaque on the tooth is cleared and better oral hygiene started, with the use of a fluoride gel. But usually a filling will be needed. If the nerve inside the tooth is infected or damaged, the roots may need to be filled using a special technique or the tooth itself removed if it's a baby (milk) tooth.

Prevention is vital to avoid tooth decay. Cut down the amount of sweet snacks your child is allowed (including acidic fizzy drinks). Help your children brush their teeth twice a day and after meals, and take them for regular check-ups at the dentist. Make sure your water supply is fluorinated or discuss fluoride drops with the dentist.

You may also want to consider fissure sealant treatment for permanent teeth.

This article was last medically reviewed by Dr Orlena Kerek in March 2009