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
Our hope is that we develop a filling material that is really permanent and does not fail in five to seven years’ time. We could really revolutionize how dental fillings are being done
“This idea came up really as an out-of-the-box thought that something revolutionary is much needed to fill this critical void,” says Neelakantan.
Neelakantan pulled together an interdisciplinary U of A team with the goal of designing a dental filling that can disinfect its own surface, either during regular chewing or with the application of ultrasound during a dentist visit
“A project of this nature requires collective intelligence and skills from specialties beyond dentistry or biomaterials,” says Neelakantan
His collaborators include Dr. A. Meldrum, professor of physics, Dr. Dan Romanyk, associate professor cross-appointed to both mechanical and biomedical engineering, Dr. Joao Soares, professor of chemical and materials engineering, ultrasound specialist Dr. Marleny Aranda Saldana, and Dr. Santiago Orrego of Temple University in Philadelphia.
The team was recently awarded one of six New Frontiers in Research Fund (NFRF) grants for U of A projects from the Social Sciences and Humanities Research Council, worth $250,000 over the next two years, and is applying for more. The NFRF grants support high-risk, high-reward Canadian-led research that transcends traditional disciplinary boundaries.
“We’ve done some strong pilot experiments and we showed that we could make the polymer,” says Neelakantan. “Now we want to make sure we are able to get consistent antimicrobial stimuli from our polymer.”
That’s the risk, but the reward will be well worth it if they are successful, Neelakantan says.
“Every time a filling breaks and we drill, we are removing part of the natural tooth structure, and over the course of time, your tooth weakens and starts fracturing,” he explains. “Our hope is that we develop a filling material that is really permanent and does not fail in five to seven years’ time
“We could really revolutionize how dental fillings are being done, and our technology could be adapted to control infection at other sites in the body as well.”
Prasanna Neelakantanis a member of theWomen and Children’s Health Research Institute, theLi Ka Shing Institute of Virologyand theCancer Research Institute of Northern Alberta.He holds an adjunct position in theDepartment of Medical Microbiology and Immunology
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