IT'S the news generations of children have been waiting for - chocolate is good for your teeth.

Researchers have discovered that antibacterial agents in cocoa beans offset the high sugar content of chocolate and reduce the chances of having tooth decay.

The agents are most plentiful in the cocoa bean husk (CBH) - the outer part of the bean normally thrown away during chocolate production.

Japanese researchers now believe the husk extract could be put in mouthwash or toothpaste to fight tooth decay.

Tooth cavities start when the bacteria which cause tooth decay, streptococcus mutans, produce a sticky molecule called glucan.

This helps the bacteria anchor themselves to teeth and form plaque. Within plaque, bacteria converts sugar to acid which eats away the tooth enamel.

Japanese researchers from Osaka University found that when CBH extract was added to a culture of S. mutans it blocked glucan production.

Rats given CBH extract in their drinking water had healthier teeth.

After three months, rats infected with S. mutans and fed a high sugar diet had 14 cavities on average. But those given CBH had no more than six.

Takashi Ooshima, who led the research, told New Scientist magazine: "It may be possible to use CBH extract in a mouthwash or toothpaste."

It could also be added to chocolate confectionery to make it better for teeth.

But good oral hygiene is still considered a much better route to healthy teeth than eating chocolate.

A spokeswoman for the British Dental Association said: "If it's true that chocolate does help reduce dental decay that can only be a good thing, but you must remember that chocolate contains sugar.

"Our advice remains the same: if people want to eat sugary sweets and drinks they should limit them to meal times, and visit their dentist regularly.