Open wide! Dental filling of the future kills bacteria and regenerates tooth
Filling contains calcium phosphate nanoparticles that rebuild tooth minerals



09:44 GMT, 4 May 2012

The dreaded trip to the dentist to replace a worn-out filling could soon be a thing of the past, thanks to a dental breakthrough.

Scientists have used nanotechnology to create the first cavity-filling composite that kills harmful bacteria and regenerates tooth structure lost to decay.

Rather than just limiting decay with
conventional fillings, the new material controls harmful bacteria, which co-exist in the natural colony
of microorganisms in the mouth.

The tooth hurts: Scientists expect their new type of dental filling to last far longer than the current standard

The tooth hurts: Scientists expect their new type of dental filling to last far longer than the current standard

It also works to remineralise the tooth, said study leader Professor Huakun Xu from Maryland University School of Dentistry.

He said: 'Tooth decay means that the mineral content in the tooth has been dissolved by the organic acids secreted by bacteria residing in biofilms or plaques on the tooth surface.

'These organisms convert carbohydrates to acids that decrease the minerals in the tooth structure.'

After a dentist drills out a decayed
tooth, the cavity still contains residual bacteria, which it's not
possible for a dentist to remove.

The researchers added antibacterial
agents containing silver nanoparticles into primer used to prepare a
drilled-out cavity and into adhesives that dentists spread into the
cavity to make a filling stick tight to the tissue of the tooth.

Prof Xu's dental weapon remineralises the tooth

Prof Xu's dental weapon remineralises the tooth

Prof Xu said: 'The reason we want to get the antibacterial agents also into primers and adhesives is that these are the first things that cover the internal surfaces of the tooth cavity and flow into tiny dental tubules inside the tooth.'

The main reason for failures in tooth restorations, says Xu, is secondary caries or decay at the restoration margins. Applying the new primer and adhesive will kill the residual bacteria. The antibacterial agent also has a high pH to limit acid production.

The prepared tooth would be filled with a nanocomposite containing calcium phosphate nanoparticles that regenerate tooth minerals.

Fillings made from the School of Dentistry's new nanocomposite, with antibacterial primer and antibacterial adhesive, should last far longer than the typical five to 10 years, though the scientists have not thoroughly tested longevity.

The new products have been laboratory tested using biofilms from saliva of volunteers.

Prof Xu's team is planning to next test its products in animal teeth and in human volunteers in collaboration with the Federal University of Ceara in Brazil.