Say goodbye to dentures: Humans could one day regrow their own teeth by copying the behaviour of a tropical fish

We only have two sets of teeth to last us a lifetime.

But cichlid fish in Lake Malawi have an endless supply. Whenever they lose a tooth, a new one drops neatly into place.

Now new research suggests humans could one day be able to regrow their own teeth in the same way as cichlids, spelling the end for dentures.

Working with hundreds of cichlids, scientists are attempting to find out which genes help the fish maintain their teeth throughout their adult lives.

By studying the chemicals that change cells into teeth and taste buds in embryonic fish, they hope to be able to turn on the tooth regrowing mechanism in humans.

The research, which also included looking at dental differences in mice, showed the process could remain active for longer than previously thought.

This suggests the process could be triggered in human adults.

Professor Todd Streelman, of Georgia Institute of Technology, said: 'We've uncovered developmental plasticity between teeth and taste buds.

'We are trying to understand the pathways that mediate the fate of cells toward either dental or sensory development.

'The potential applications to humans makes this interesting to everybody who has dealt with dental issues at one time or another in their lives.'
Lake Malawi's extraordinary population of cichlids evolved from a single ancestor thousands of years ago.

It's hoped the fish could hold the key to helping almost 60 percent of the human population who have lost all their teeth by the time they reach sixty.

Beyond the painful dental health issues, this can causes medical and nutritional problems that can shorten life.

The study, published in the journal Proceedings of the National Academy of Sciences, found the teeth and taste buds grow from the same surface tissues in embryonic fish.

Unlike humans fish have no tongues so their taste buds are mixed in with their teeth - sometimes in adjacent rows.

The Lake Malawi cichlids have adapted their teeth and taste buds to thrive in the unique conditions where they live.

One species eats plankton and needs few teeth because it locates its food by sight and swallows it whole.

Another lives on algae which has to be scraped or snipped from rocky lake formations -  needing both many more teeth and more taste buds to distinguish food.

By studying the genetic differences in the fish - and mice - the scientists believe it's possible the same tissue in humans could also be able to regenerate new teeth.

By bathing embryonic fish in chemicals that influence the developmental pathways, they boosted the growth of taste buds at the expense of teeth.

These changes began just five or six days after the fish eggs were fertilised at a stage when the fish had eyes and a brain - but were still developing jaws.

Professor Streelman said: 'There appear to be developmental switches that will shift the fate of the common epithelial cells to either dental or sensory structures.'

Teeth and taste buds begin in the same kind of epithelial tissue in the developing jaws of embryonic fish and differentiate later forming teeth with hard enamel - or soft taste buds.

'It's not until later in the development of a tooth that it forms enamel and dentine,' Streelman added.

'At the earliest stages of development, these structures are really very similar.

'It was not previously thought development would be so plastic for structures that are so different in adult fish.

'Ultimately this suggests the epithelium in a human's mouth might be more plastic than we had previously thought.

'The direction our research is taking, at least in terms of human health implications, is to figure out how to coax the epithelium to form one type of structure or the other.'

But the researchers would also need to understand how nerves and blood vessels grow into teeth to make them viable.

They are now working to find out how far into adulthood the plasticity between teeth and taste buds extends - and what can trigger the change.