10/14/13  Portland, Ore.

Two National Institutes of Health grants will allow dental researchers to explore longer-lasting composites for filling teeth

Oregon Health & Science University's School of Dentistry researchers recently received nearly $3 million in grants from the National Institute of Dental and Craniofacial Research, a branch of the National Institutes of Health (NIH), to study novel materials for longer-lasting dental composites, or fillings.

Principal investigators Carmem Pfeifer, D.D.S., Ph.D., assistant professor of biomaterials and biomechanics, and Jack Ferracane, Ph.D., chair and professor of restorative dentistry, will receive more than $2.4 million over five years to work independently toward the common goal of doubling the service life of dental composites. Their study is titled “Tertiary Methacrylamides and Thiourethane Additives as Novel Dental Composites.”

Current dental composites — the materials developed in the 1960s for tooth-colored restorations that harden when exposed to blue light — degrade over time.

“Restorations made with the current materials last on average six to seven years before they fail,” said Pfeifer. “Restorations are particularly susceptible to hydrolysis [when the material comes into contact with water in saliva] or are attacked by the naturally occurring enzymes that produce bacteria in peoples’ mouths.”

The OHSU School of Dentistry study will use new compounds to replace the current material based on methacrylates. The new materials will be more resistant to hydrolysis and enzymatic attack.

“Our materials will be based in methacrylamide chemistry, and won’t require that the dentist change operatory procedures before placing the composite,” said Pfeifer. “Our materials will still be activated by blue light and placed the same way as before,” adding that the OHSU study will incorporate pre-polymerized additives to make the new materials stronger. The OHSU team will test the basic mechanical resistance of the new materials as a screening tool, and then use bioreactors to simulate the conditions in the oral environment.

Pfeifer also recently received a three-year, $429,600 NIH grant to study “Thiourethanes as low-stress modifiers in dental composites.” Dental student research is a key part of the OHSU School of Dentistry’s curriculum and many dental students are actively pursuing research along with their dental studies. Student involvement is a key component of this grant, with dental students directly involved in helping to formulate, characterize, and test the newly developed composite materials, Pfeifer explained.