by ANASTASIA STEPHENS, Daily Mail

Dentists may soon be out of business, thanks to a vaccine that could rid us of tooth decay for ever.

Researchers in the U.S., at the Forsyth Institute in Boston, are researching a vaccine that targets mutans streptococci, the bacterium causing tooth decay.

When the bacteria break down food, they produce lactic acid, which wears away tooth enamel, producing cavities.

The cavity-fighting vaccine teaches the immune system to make antibodies that kill the enzymes which enable bacteria to stick to teeth. Unable to cling to tooth enamel, the bacteria are washed away by saliva, and the teeth are protected.

In experiments, rats given the vaccine developed almost no cavities. Trials on people have also found the vaccine to have a similar effect.

Ultimately, however, the vaccine would be given to children under the age of one while their teeth are developing, but before the plaque bacteria have become established.

'If given to children at a young age, we think it may prevent colonisation of plaque bacteria altogether,' says Dr Daniel Smith of the Forsyth Institute.

'The bacteria wouldn't be able to stick to teeth or gain a foothold. Children would be protected from caries for life.'

Given to adults, the vaccine protects teeth and reduces, rather than eradicates, bacteria in the mouth. It will probably be administered as nasal drops, sparing children and adults the ordeal of painful injections.

'The nose and mouth are connected. If you give the vaccine nasally, you get antibodies in the saliva,' says Dr Smith.

Dr Jacinta Yeo, of the British Dental Association, believes the vaccine, which may be available in a few years, could revolutionise dental health. 'The research sounds exciting. If bacteria can't stick to teeth, they can't do harm,' she says.

'Saliva can neutralise acids and kill bacteria, but it's not effective enough to prevent damage by bacterial acids. It sounds as if this vaccine could equip the body with a natural defence system.'