Oregon Health & Science University (OHSU) researchers have developed a new dental adhesive and composite that, when combined, deliver longer-lasting dental restorations. The findings may lead to a more resistant dental composite and fewer trips to the dentist to have worn restorations replaced.
The study, “Use of (Meth)acrylamides as Alternative Monomers in Dental Adhesive Systems,” published in Dental Materials, describes how the adhesive was found to be 30% stronger after six months in use than adhesives currently used to hold dental composites in place.
In February 2019, the team published findings in Scientific Reports on a new composite infused with thiourethane—the same protective coating used for cars—that is two times more resistant to breakage than standard dental composites. These qualities allow it to hold up better to mastication than traditional composites. Jack Ferracane, PhD, chair and professor of restorative dentistry in the OHSU School of Dentistry, led the materials’ development.
“Every time we need to replace a restoration, more tooth structure is lost, and what started as perhaps a small lesion can turn into a large one—possibly requiring root canal treatment,” reports Carmem Pfeifer, DDS, PhD, an associate professor of restorative dentistry in the OHSU School of Dentistry, and corresponding author of the studies published in Scientific Reports and Dental Materials. Noting the more a dentist needs to drill, the weaker the tooth becomes, she suggests this material will decrease the likelihood of the tooth being further compromised.
While clinical trials are needed to determine how the material stands up in treatment, the researchers hold a positive outlook. “Based on the comparative performance of these materials with the commercially available controls, we project the restorations will last longer than today—with the important benefit that new caries lesions underneath the restorations will be less likely,” says Pfeifer. “This will mean the dentist does not have to replace the restorations as often, which, in turn, helps preserve natural tooth structure.”
The team is currently testing the adhesive and composite in vitro. Using a bioreactor and simulated cavity model, the researchers simulate caries in extracted teeth and incubate them in the presence of caries-forming bacteria. The machine then cycles through chewing motions to simulate the restoration in use.
Featured image: Steven Lewis, research associate in the Pfeifer Polymers Lab at OHSU’s School of Dentistry, runs an experiment to test filler particles which are part of composite restorations, Feb. 19, 2019. (OHSU/Kristyna Wentz-Graff)