Combine a diet high in sugar with poor oral hygiene habits and dental cavities, or caries, will likely result. The sugar triggers the formation of an acidic biofilm, known as plaque, on the teeth, eroding the surface. Early childhood caries is a severe form of tooth decay that affects one in four children in the U.S. and millions globally. It's a particularly severe problem in underprivileged populations.
In a study published in Nature Communications, researchers led by Dr. Michel Koo, Professor at Penn Dental Medicine, showed that twice-daily rinses with FDA-approved nanoparticles and hydrogen peroxide effectively disrupted biofilms and prevented tooth decay in both an experimental human-plaque-like biofilm and in an animal model that mimics early-childhood caries.
The nanoparticles break apart dental plaque through a unique pH-activated antibiofilm mechanism.
"The nanoparticles act as a peroxidase, activating hydrogen peroxide, a commonly used antiseptic, to generate free radicals that dismantle and kill biofilms in pathological acidic conditions but not at physiological pH, thus providing a targeted effect," says Koo.
Because the caries-causing plaque is highly acidic, the new therapy can precisely target pathogenic biofilms without harming the surrounding oral tissues or microbiota.
The particular iron-containing nanoparticle used in the experiments, ferumoxytol, is already FDA-approved to treat iron-deficiency, a promising indication that a topical application of the same nanoparticle would also be safe for human use.
"We used plaque samples from caries-active subjects to reconstruct these highly pathogenic biofilms on real human tooth enamel," says Koo. "This simulation showed that our treatment not only disrupts the biofilm but also prevents mineral destruction of the tooth's surface."
As further evidence of the treatment's targeted effect, the researchers found no significant change in the microbiome in the mouth after therapy and no signs of tissue damage.
Incorporating nanoparticles in a rinse or toothpaste could be a cost-effective way to significantly improve their effectiveness, says Koo. With evidence backing this approach in both an animal model and a human-like model of tooth decay, the research team is working to test its clinical efficacy.
Koo was recently awarded the IADR William H. Bowen Research in Dental Caries Award for his consistent record of developing innovative ways to treat caries.
