Teeth could be repaired or regrown
Scientists believe they have found a way to grow teeth in the laboratory, a discovery that could put an end to fillings and dentures.
The US team from Oregon have located the gene responsible for the growth of enamel, the hard outer layer of teeth which cannot grow back naturally.
Other scientists are already growing the inner parts of teeth in animals - but they have no hard enamel coatings.
The Proceedings of the National Academy of Sciences work may plug this gap.
Experiments in mice have shown that the gene, a "transcription factor" called Ctip2, has several functions involving immune responses and the development of skin and nerves.
The work at Oregon State University made the link with enamel by studying mice bred to lack Ctip2.
Lead researcher Dr Chrissa Kioussi said: "It's not unusual for a gene to have multiple functions, but before this we didn't know what regulated the production of tooth enamel."
The scientists found that Ctip2 was crucial for the enamel-producing cells, called ameloblasts, to form and work properly.
Dr Kioussi said: "This is the first transcription factor ever found to control the formation and maturation of ameloblasts, which are the cells that secrete enamel."
Controlling the gene in conjunction with stem-cell technology could make the artificial creation of functional teeth a real possibility.
Alternatively, the knowledge could be used to strengthen existing enamel and repair damaged enamel, cutting decay and the need for fillings.
Dr Kioussi said: "A lot of work would still be needed to bring this to human applications, but it should work. It could be really cool, a whole new approach to dental health."
Paul Sharpe, an expert on tooth development at the Dental Institute at King's College London, said: "If you could find some way of growing ameloblasts that make enamel, you could find a way to repair teeth.
"Any gene like this is worth understanding. The more we learn about it the more we can use the information to make biological models of tooth repair."