A University of Alberta research lab is leading the development of a new generation of self-sterilizing materials for dental fillings.
The rationale for the project comes from the Minamata Convention on Mercury, a worldwide agreement to phase out the manufacture, import or export of dental amalgam containing mercury by 2034.
While the Canadian Dental Association still considers mercury amalgam fillings safe for most patients, they currently account for less than 10 per cent of all fillings used, and Health Canada advises dentists to avoid using it for pregnant women, people with kidney disease, and children whenever possible.
"Almost every adult develops at least one decayed tooth in their lifetime, and historically these decayed teeth were all filled with a metallic filling that was based on silver and mercury," explains principal investigator Dr. Prasanna Neelakantan, associate professor and Alberta Dental Association & College Chair in Oral Health Research in the Mike Petryk School of Dentistry.
The best replacements available to date are polymer-based fillings that shrink and degrade.
"The statistics show that 100 million dental fillings are placed in North America alone per year. Alarmingly, these fillings fail within five to seven years," Neelakantan notes, adding that these fillings cannot prevent new decay from developing.
"Some researchers have attempted to embed antibiotics or antiseptics into the coatings of fillings to protect them from decay, but these materials degrade over time and lose their antiseptic properties once all the additives leach out," he says.
He wondered if it would be possible to design a polymer that would disinfect its own surface so the fillings would not degrade.
After research and discussion with students and collaborators, the lab identified several types of polymers that have self-disinfecting properties when pressure is applied.
