Lost and broken teeth could one day be regrown, scientists believe after finding the stem cells responsible for tooth formation and the gene that switches it on.

Scientists at the University of Plymouth discovered a new group of stem cells which form skeletal tissue and contribute to the making dentin - the hard tissue that surrounds the main body of the tooth. They also showed that a gene called Dlk1 sparks the stem cells into action, so they can mend damage such as decay, crumbling or cracked teeth.

Currently there is nothing to be done to repair damaged teeth apart from fillings or crowns.

But the body clearly has the capability of growing new teeth as seen by the new sets which grow back in childhood after the milk teeth fall out.

Dr Bing Hu, who led the research said: “Stem cells are so important, as, in the future, they could be used by laboratories to regenerate tissues that have been damaged or lost due to disease - so it's vital to understand how they work.

“By uncovering both the new stem cells that make the main body of a tooth and establishing their vital use of Dlk1 in regenerating the tissue, we have taken major steps in understanding stem cell regeneration.