Nanoparticle May Stop Tooth Decay Before it Starts

Scientists have created a nanoparticle that might provide an alternative treatment that would help prevent caries, rather than treat lesions once they impact dentition. This new cerium nanoparticle formation could potentially be applied to teeth in the dentist’s office. 

The project’s lead investigator Russell Pesavento, DDS, PhD, an assistant professor at University of Illinois at Chicago (UIC) College of Dentistry, would like to see an intraoral agent that would prevent caries and not “randomly kill” bacteria in the mouth. His team presented the early stages of this proof of concept at the American Chemical Society Fall 2020 Virtual Meeting & Expo.

Streptococcus mutans are associated with caries, as the bacteria create an adherent biofilm that is not easily removed with daily brushing. The acid byproducts created as the bacteria metabolizes sugar negatively affect dentition by dissolving tooth enamel, creating a pathway for caries to form. Pesavento and team prepared cerium oxide nanoparticles by dissolving ceric ammonium nitrate or sulfate salts in water. When researchers seeded polystyrene plates with S. mutans in growth media and fed the bacteria sugar in the presence of the cerium oxide nanoparticle solution, the formulation reduced biofilm adherence by 40% compared to plates without these specific nanoparticles—though they weren’t able to dislodge existing biofilms. Neither silver nitrate nor other commercially available cerium oxide formulations showed a reduction in biofilm adherence under similar conditions.  They also found they didn’t kill the bacteria under these conditions. 

Unlike other treatments that kill many types of oral bacteria, this formulation appears to only inhibit plaque by limiting its ability to stick to a surface. “Right now, we can coat the particles and stabilize them in the pH 7-8 region, which is the area of the pH of saliva, and they have retained activity,” he says. “ We are trying to make it more suitable for future application in the oral cavity.”

Researchers will test the formulation in the presence of other microbial strains typically present in the oral cavity, as well as test its effects on human cells of the lower digestive tract to ensure its safety in these applications.

Pesavento is also working with bacteria linked to the development of gingivitis and has found one particular coated nanoparticle that outcompeted stannous fluoride in limiting the formation of adherent biofilms under similar conditions, according to the American Chemical Society. 

Pesavento acknowledges funding from the National Institute of Dental and Craniofacial Research.