Professor Nigel Pitts, from the university's Dental Institute, said:
"The way we treat teeth today is not ideal. When we repair a tooth by putting in a filling, that tooth enters a cycle of drilling and re-filling as, ultimately, each 'repair' fails.
"Not only is our device kinder to the patient and better for their teeth, but it's expected to be at least as cost-effective as current dental treatments.
"Along with fighting tooth decay, our device can also be used to whiten teeth."
A Scottish firm, Reminova Ltd, is now trying to find private investment to develop the technique.
Tooth decay could soon be treated with a painless "remineralisation" technique developed in London, that means damaged enamel repairs itself, dentists said today.
The technique, which spells the end of drilling, could be available in three years.
The new treatment, developed at King's College London, is called Electrically Accelerated and Enhanced Remineralisation and is expected to cost around the same as fillings.
It speeds up the natural movement of calcium and phosphate minerals into the damaged tooth, which then repairs itself.
Decay is normally removed by drilling, followed by a filling with a material such as amalgam or composite resin.
The new process prepares the damaged area of enamel, then uses a tiny electric current to push minerals into the repair site so the enamel can repair itself.
Researchers at some of London's top hospitals are to receive£28 million pounds of government money to study the impact long termconditions on the NHS.
The money will fund thirteen pioneering teams at Kings,Chelsea and Westminster and Bart's Healthcare Trust.
Scientists at King's College are celebrating the 21st birthday of a special unit dedicated to sets of twins.
12,000 siblings have been registered with the Department of Twin Research, since it was set up in 1992 to carry out genetic tests. Sangeeta Kandola reports.