Doctors believed it to be impossible, now scientists find it to be possible.

Scientists in France are working on a gel, containing melanocyte-stimulating hormone (MSH) which works by promoting cells in teeth, to start multiplying.

This gel that can help decayed teeth grow back can mean the end to fillings (and the painful drilling!) – researchers say that in lab studies, it took just four weeks to fully restore teeth in their original healthy state.

They are saying that the gel will be ready in 3-5 years time.