Home > Press > New nanocomposites may mean more durable tooth fillings
|A calcium phosphate nanocomposite filling in a tooth. The nanocomposite can "smartly" release decay-fighting agents to buffer against acids produced by bacteria, and rebuild the lost tooth minerals by releasing ions into the mineral-deficient area of the tooth.|
The mouth is a tough environment—which is why dentists do not give lifetime guarantees. Despite their best efforts, a filling may eventually crack under the stress of biting, chewing and teeth grinding, or secondary decay may develop where the filling binds to the tooth. Fully 70 percent of all dental procedures involve replacements to existing repairs, at a cost of $5 billion per year in the United States alone.
New nanocomposites may mean more durable tooth fillings
Gaithersburg, MD | Posted on April 27th, 2007
Now, however, scientists at the American Dental Association's Paffenbarger Research Center, a joint research program at the National Institute of Standards and Technology (NIST), have shown that nanotechnology has the potential to lessen that toll by producing tooth restorations that are both stronger than any decay-fighting fillings available today, and more effective at preventing secondary decay. They report their findings in a recent issue of The Journal of Dental Research.*
The researchers' new technique solves a problem with the standard composite resin filling, a natural-looking restoration that is the method of choice when appearance is an issue. A dentist creates the filling by mixing the pure liquid resin with a powder that contains coloring, reinforcement and other materials, packing the resulting paste into the cavity, and illuminating the tooth with a light that causes the paste to polymerize and harden. For decay-fighting composite fillings, the problem arises from an additive that is included in the powder to provide a steady release of calcium and phosphate ions. These ions are essential to the long-term success of the filling because they not only strengthen the crystal structure of the tooth itself, but buffer it against the decay-causing acid produced by bacteria in the mouth. Yet the available ion-releasing compounds are structurally quite weak, to the point where they weaken the filling as a whole.
To get around this conundrum, the Paffenbarger researchers have devised a spray-drying technique that yields particles of several such compounds, one of which being dicalcium phosphate anhydrous, or DCPA, that are about 50 nanometers across—20 times smaller than the 1-micrometer particles in a conventional DCPA powder. Because these nanoscale particles have a much higher surface to volume ratio, they are much more effective at releasing ions, which means that much less of the material is required to produce the same effect. That, in turn, leaves more room in the resin for reinforcing fibers that strengthen the final filling. To exploit that opportunity, the Paffenbarger researchers also have developed nanoscale silica-fused fibers that produce a composite resin nearly twice as strong as the currently available commercial variety.
* H.H.K. Xu, M.D. Weir, L. Sun, S. Takagi and L.C. Chow. Effects of calcium phosphate nanoparticles on Ca-PO4 composite, J Dent Res 86(4):378-383m 2007.
About National Institute of Standards and Technology (NIST)
From automated teller machines and atomic clocks to mammograms and semiconductors, innumerable products and services rely in some way on technology, measurement, and standards provided by the National Institute of Standards and Technology.
Founded in 1901, NIST is a non-regulatory federal agency within the U.S. Commerce Department's Technology Administration. NIST's mission is to promote U.S. innovation and industrial competitiveness by advancing measurement science, standards, and technology in ways that enhance economic security and improve our quality of life.
For more information, please click here
Michael E. Newman
Copyright © National Institute of Standards and Technology (NIST)
If you have a comment, please Contact
Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.
ORNL microscopy pencils patterns in polymers at the nanoscale December 17th, 2014
Pb islands in a sea of graphene magnetise the material of the future December 16th, 2014
Graphene Applied in Production of Recyclable Electrodes December 13th, 2014
A golden thread through the labyrinth of nanomaterials December 12th, 2014
Creation of 'Rocker' protein opens way for new smart molecules in medicine, other fields December 18th, 2014
How does enzymatic pretreatment affect the nanostructure and reaction space of lignocellulosic biomass? December 18th, 2014
Silicon Valley-Based Foresight Valuation Launches STR-IP™, a New Initiative for Startups to Discover the Value of Their Intellectual Property December 18th, 2014
Iranian Scientists Use Nanotechnology to Increase Power, Energy of Supercapacitors December 18th, 2014
Longhorn beetle inspires ink to fight counterfeiting November 5th, 2014
Iran-Made Respiratory Nano Masks Provided to Hajj Pilgrims October 23rd, 2014
Japanese gold leaf artists worked on a nano-scale: Study demonstrates X-ray fluorescence spectroscopy is a non-destructive way to date artwork July 3rd, 2014
Harry Potter-style invisibility cloaks: A real possibility next Christmas? Forget socks and shaving foam, the big kids of tomorrow want an invisible cloak for Christmas December 19th, 2013
Nanocomposites Strengthen Bone Implants November 13th, 2014
NYU Researchers Break Nano Barrier to Engineer the First Protein Microfiber October 23rd, 2014
Nanoparticles Used to Improve Quality of Bone Cement September 29th, 2014
Diagnostic tool for therapeutic plasma medicine September 8th, 2014