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News / July 15, 2009

New tooth tech will fill the gap for longer

by Guy Hiscott

A dental expert has come up with an idea to extend the life of a tooth filling.

The researcher at the US Medical College of Georgia is hoping that a new nanotechnology technique will extend the fillings’ longevity.

Dr Franklin Tay, associate professor of endodontics in the MCG School of Dentistry, explains: ‘Dentin adhesives bond well initially, but then the hybrid layer between the adhesive and the dentin begins to break down in as little as one year. When that happens, the restoration will eventually fail and come off the tooth.’


Half of all tooth-coloured composite resin restorations fail within 10 years, and about 60% of all operative dentistry involves replacing them, according to research in the Journal of the American Dental Association.


Dr Tay aims to prevent the ageing and degradation of resin-dentin bonding by feeding minerals back into the collagen network.


With a two-year, $252,497 grant from the National Institute of Dental & Craniofacial Research, he will investigate guided tissue remineralisation, a new nanotechnology process of growing extremely small, mineral-rich crystals and guiding them into the demineralised gaps between collagen fibres.


His idea came from examining how crystals form in nature.


He says: ‘Eggshells and abalone [sea snail] shells are very strong and intriguing. We’re trying to mimic nature, and we’re learning a lot from observing how small animals make their shells.’


The crystals, called hydroxyapatite, bond when proteins and minerals interact. Dr Tay will use calcium phosphate, the primary component of dentin, enamel and bone, and two protein analogs also found in dentin so he can mimic nature while controlling the size of each crystal.


Dr Tay says: ‘When crystals are formed, they don’t have a definite shape, so they are easily guided into the nooks and crannies of the collagen matrix.’


In theory, the crystals should lock the minerals into the hybrid layer and prevent it from degrading. If Dr Tay’s concept of guided tissue remineralisation works, he will create a delivery system to apply the crystals to the hybrid layer after the acid-etching process.


‘Instead of dentists replacing the teeth with failed bonds, we’re hoping that using these crystals during the bond-making process will provide the strength to save the bonds,’ Dr. Tay says.


“Our end goal is that this material will repair a cavity on its own so that dentists don’t have to fill the tooth.’