These nanoparticles, which have been approved by the U.S. Food and Drug Administration, break apart dental plaque, called acidic biofilm, through a unique pH-activated mechanism. Photo by Milenafoto/Wikimedia Commons
Aug. 1 (UPI) -- Researchers have found nanoparticles disrupt plaque and prevent tooth decay in a study of tooth enamel-like material and rodents.
These nanoparticles, which have been approved by the U.S. Food and Drug Administration, break apart dental plaque, called acidic biofilm, through a unique pH-activated mechanism. The findings, by researchers at University of Pennsylvania in the dental, medical and engineering and applied science schools, were published Tuesday in Nature Communications.
Sugar triggers the formation plaque on teeth, eroding the surface and leading to cavities.
But the researchers found a way to erode plaque with the bioparticles, which are used to treat iron deficiency.
"It displays an intriguing enzyme-like property whereby the catalytic activity is dramatically enhanced at acidic pH but is 'switched off' at neutral pH conditions," Dr. Hyun Koo, a professor in Penn Dental Medicine's Department of Orthodontics, said in a press release. "The nanoparticles act as a peroxidase, activating hydrogen peroxide, a commonly used antiseptic, to generate free radicals that potently dismantle and kill biofilms in pathological acidic conditions but not at physiological pH, thus providing a targeted effect."
Koo believes incorporating nanoparticles in a mouth rinse or toothpaste could be effective. He noted many of thee products already contain hydrogen peroxide and only a small amount of relatively inexpensive nanoparticles would need to be added.
The new therapy targets the tooth's caries-causing plaque, which is highly acidic, without harming the surrounding oral tissues or microbiota because it.
They believe nanoparticles at several-hundred-fold lower concentration than for iron deficiency would also be safe for human use in the mouth.
Researchers first conducted experiments on tooth-enamel-like material, and then they conducted experiments that more closely replicated the conditions of the human mouth.
"We used plaque samples from caries-active subjects to reconstruct these highly pathogenic biofilms on real human tooth enamel," Koo said. "This simulation showed that our treatment not only disrupts the biofilm but also prevents mineral destruction of the tooth's surface."
The researchers found no significant change in microbes in the mouth after therapy and no signs of tissue damage.
"This therapy isn't killing microorganisms indiscriminately, but rather it is acting only where the pathological biofilm develops," Koo said.
In studies with rodents, twice-a-day rinses of ferumoxytol and hydrogen peroxide greatly reduced the severity of caries on all of the surfaces of the teeth and totally blocked the formation of cavities in the enamel.
