Polished to perfection( This release is available in A HREF ...),Health

Brush your teeth twice a day! Any child knows these days that regular tooth care is the only way to banish the bacteria that cause caries. Yet sometimes that is not enough. The tooth surface wears down and gets uneven ?and the problem is that dental plaque adheres particularly well to a rough surface. Dentists therefore offer professional cleaning services, removing plaque and discoloration with abrasive prophylactic pastes. This renders the tooth surface beautifully smooth, making it difficult for bacteria to gain a foothold. Yet there is a risk that the polishing treatment will also grind away precious tooth enamel and dentin at the exposed necks of teeth. The manufacturers therefore have to find the happy medium when developing their prophylactic pastes: The pastes should be just abrasive enough to remove superficial discoloration and plaque, but preferably not wear down the tooth enamel.

Until now, scientists lacked any realistic objective measuring techniques to assess tooth abrasion caused by chewing and by the effect of toothpastes. A leading manufacturer of dental hygiene products asked the Fraunhofer Institute for Mechanics of Materials IWM in Freiburg, one of whose specialties is the analysis and visualization of surface roughness, to help them develop new prophylactic pastes. The effectiveness of a prophylactic paste has so far been measured by how well the granules that it contains are able to smoothen a rough surface. The test is performed by first roughening tooth enamel or denture materials such as ceramics and titanium to a precisely defined value with an aggressive grinding material. But this does not truly reflect reality, as chewing wears out different materials at different rates. The new measuring method developed by the IWM researchers, a kind of chewing simulation, takes this factor
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