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Member Research and Reports

Member Research and Reports

Naturally Occurring Amino Acid Could Improve Oral Health, Michigan Finds

Arginine, a common amino acid found naturally in foods, breaks down dental plaque, which could help millions of people avoid cavities and gum disease, researchers at the University of Michigan and Newcastle University have discovered.

Rickard Foxman
[Photo: Dr. Alexander Rickard (left) and Dr. Betsy Foxman]

Dr. Alexander Rickard, assistant professor of epidemiology at the University of Michigan School of Public Health, and colleagues discovered that in the lab L-arginine — found in red meat, poultry, fish, and dairy products, and already used in dental products for tooth sensitivity — stopped the formation of dental plaque.

“This is important as bacteria like to aggregate on surfaces to form biofilms. Dental plaque is a biofilm,” Dr. Rickard said. “Biofilms account for more than 50 percent of all hospital infections. Dental plaque biofilms contribute to the billions of dollars of dental treatments and office visits every year in the United States.”

Dental biofilms are the culprits in the formation of dental caries (cavities), gingivitis, and periodontal disease. Surveys indicate that nearly 24 percent of adults in the United States have untreated dental caries, and about 39 percent have moderate-to-severe periodontitis, a number that rises to 64 percent for those over age 65.

Most methods for dental-plaque control involve use of antimicrobial agents, such as chlorhexidine, which are chemicals aimed at killing plaque bacteria, but they can affect sense of taste and stain teeth. Antimicrobial treatments have been the subject of debate about overuse in recent years.

Pending further clinical trials to verify their lab findings, the researchers said L-arginine could take the place of the current plaque-controlling biocide substances including chlorhexidine and other antimicrobials.

The mechanism for how L-arginine causes the disintegration of the biofilms needs further study, the researchers said. It appears arginine can change how cells stick together, and can trigger bacteria within biofilms to alter how they behave so that they no longer stick to surfaces, they said.

In conducting their research, team members used a model system they introduced in 2013 that mimics the oral cavity. The researchers were able to grow together the numerous bacterial species found in dental plaque in the laboratory, using natural human saliva.

“Other laboratory model systems use one or a small panel of species,” Dr. Rickard said. “Dental plaque biofilms can contain tens to hundreds of species, hence our model better mimics what occurs in the mouth, giving us great research insight.”

U-M School of Public Health epidemiology professor Dr. Betsy Foxman also contributed to the study.

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