'Nanospheres' That Block Pain Of Sensitive Teeth

Preliminaryresearch presented today at the Institute of Physics conferenceEMAG-NANO 2005 shows that creating tiny spheres of a ceramic materialcalled hydroxyapatite could be a long term solution or cure forsensitive teeth.

Sensitive teeth or ‘dental hypersensitivity’ isa condition that arises when the dentine of the tooth is exposed. Thedentine is made up of thousands of tiny fluid-filled channels whichradiate outwards from the nerve endings at the centre of the tooth.Heat, some chemicals, and physical contact can cause the fluid in thesechannels to move – in or out – triggering the nerve endings and causingsharp pain.

If these channels (or ‘tubules’) are fully orpartially blocked, the flow can be reduced and the pain stopped orsignificantly reduced. Currently, the only way to treat this conditionis through good dental hygiene – using special toothpastes and fluorinemouthwashes which encourage re-mineralization of the dentine coating.

JonathanEarl, David Wood and Steve Milne from the Institute of MaterialsResearch at the University of Leeds have found that the most successfulparticle shape for filling these channels is a ‘nanosphere’ and are nowtrying to synthesize nanospheres of hydroxyapatite. Hydroxyapatite is aceramic material which is highly compatible with teeth and bone and sois widely used by medics for bone grafts or dental coatings (because itbinds strongly with the bone material).

Earl and his colleaguesgrew hydroxyapatite at various pH levels to vary the size of theparticles it is made up of. At normal pH, it is composed of longrod-like structures but at high pH levels the particles ofhydroxyapatite become smaller and more rounded, better for fittinginside the tiny channels in teeth.

To see whether nanosphereswould be successful at filling the channels they used commerciallyavailable silica nanospheres of around 40nm in diameter.

Earlsaid: “We found these tiny spheres are really good at filling thechannels in teeth, packing inside them quite evenly and going down theholes to a good depth. They'd be the perfect shape of particle forfilling these channels and reducing or preventing the pain caused bysensitive teeth”.

The next stage of their research will be towork out how to synthesize nanospheres of hydroyapatite or acombination of hydroxyapatite and fluorine which would fill the holesand encourage re-mineralization at the same time and so be anincredibly powerful repair tool for dentists.