29 May 2009

New treatment could banish dental fillings

By
Cosmos Online
Australian scientists have invented a liquid which repairs damage to tooth enamel while you sleep, according to research presented this week.
Dental treatment

The technology should be available within five years, and will be able to fight early stage tooth-decay without the need for expensive, painful fillings. Credit: iStockphoto

SYDNEY: Australian scientists have invented a liquid which repairs damage to tooth enamel while you sleep, according to research presented this week.

The technology should be available within five years, and will be able to fight early stage tooth decay without the need for expensive, painful fillings, they said.

“As a working dentist, I thought that there needs to be a better way to treat this problem,” said Nathan Cochrane, a dental scientist from the University of Melbourne. He presented his work at the annual meeting of the Australian Collaborative Research Centres Association (CRCA) in Canberra this week.

History of decay

Tooth decay has plagued humanity throughout history. Our teeth are covered in a community of bacteria, which feed on carbohydrates in the mouth. They excrete acid as a waste product, wreaking havoc on tooth enamel, said Cochrane. The acid gradually erodes the enamel, showing as whitish spots on teeth. Eventually the enamel collapses in on itself, painfully exposing the sensitive inner parts of the tooth.

For over 100 years, the only treatment has involved boring into the tooth, removing the rotting material and refilling the hole with metal. Fillings, however, are prone to failure, often need replacing, look ugly and can be painful to install. To find a better solution to the early stages of tooth decay, Cochrane’s team turned to the molecules which enamel is made of.

They found that they could reverse some of the damage by immersing teeth in a solution containing calcium, phosphate and fluoride – the building blocks of tooth enamel. In the lab, they exposed fragments of damaged enamel, chipped off dead wisdom teeth, to various formulations of the solution. Under the right conditions, the solution infused into the damaged enamel, repairing the crystalline structure from within.

Magic ingredient

A protein, casein phosphopeptide, isolated from milk, proved to be the secret ingredient. Under natural conditions, this protein helps babies grow bones; in the solution it stabilises the building blocks required for repair. Appropriate pH also turned out to be vital – at an acidic pH of 5.5, the molecules combined into a special, electrically neutral, deep-penetrating form.

The researchers tested the quality of repaired tooth enamel in the lab using an electron microscope. The results revealed that the solution had penetrated the tooth, and restored the enamel in three dimensions, rather than just on the surface as in traditional fluoride treatment. “The enamel we developed was more resistant to future attacks,” said Cochrane.

A similar product, ‘tooth mousse’, was developed by the same team. However it is a cream, not a liquid, and is thought to be less efficient at penetrating teeth.

A clinical trial testing the effectiveness of the new treatment in people is about to begin. Patients will be fitted with a custom-made mouth tray, tightly moulded to the shape of their teeth. In the mouth, a saliva-proof sealing gel will hold the tray in place and the solution will be squirted into the tray’s cavity through a valve, surround the teeth.

The invention has the potential to stop tooth decay dead in its tracks – provided you go to the dentist early enough, said Cochrane. He cautioned that by the time a hole appears, it’s too late for this treatment to be effective. Prevention and regular check ups are the best cure, he stressed.

Paul Sharpe, from the Dental Institute at Kings College London, in Britain, agrees that the technique may be a good preventative. “Treatments such as this one may help protect or strengthen enamel,” he told Cosmos Online.

Being able to grow totally new enamel, however, is a long way off, but might one day be possible with stem cell treatments. “Tooth enamel is a very complex and intricate substance whose formation is orchestrated by special cells,” he said.

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