Arginine, a naturally occurring amino acid, may counteract the destructive effects of dental biofilms, in turn reducing the risk of caries, according to an article published on January 11 in SciTech.
A group of researchers, led by doctoral student Yumi C. Del Rey and Dr. Sebastian Schlafer of the department of dentistry and oral health at Aarhus University in Denmark, grew biofilms and tested arginine’s effects in people with active tooth decay. They found that arginine altered the makeup of dental biofilms in multiple ways. The findings were published in the International Journal of Oral Science.
Biofilm, that colorless, “fuzzy” layer that forms on teeth, ultimately hardening into plaque on teeth, becomes a hub for producing acid and inflammation that leads to cavities and gingivitis.
To investigate the impact of arginine -- an amino acid found in meat, nuts, legumes, and some dairy products -- on the pH, bacterial composition, and carbohydrate structure of biofilms in patients with active tooth decay, 12 people with active caries were fitted with specially designed dentures that enabled biofilm growth on both sides of the jaw, allowing a comparison of treatments.
The dentures were immersed in a sugar solution for five minutes, followed by a 30-minute treatment with distilled water or arginine. This process was repeated three times daily, with arginine applied to the same side. After four days, when biofilm grew, the dentures were removed and analyzed.
Using a pH-sensitive dye, C-SNARF-4, researchers measured the pH inside the biofilms. The biofilms exposed to the arginine treatment had a higher pH, or lower acidity, at 10 minutes and 35 minutes after being exposed to the sugar solution.
“Our results revealed differences in acidity of the biofilms, with the ones treated with arginine being significantly more protected against acidification caused by sugar metabolism,” said Del Rey.
Arginine also reshaped the biofilms’ makeup and the oral microbiome
Besides reducing the acidity of biofilms, arginine changed the biofilms’ structure by reducing galactose-containing carbohydrates. Galactose and fucose significantly comprise biofilms, creating acidic “pockets” that further contribute to tooth decay. Arginine changed the spatial distribution of both carbohydrates, possibly weakening the biofilm’s harmful effects, the researchers said.
Lastly, the studied biofilms mainly comprised the Streptococcus and Veillonella species. Streptococci also produce acid. The arginine significantly reduced the mitis/oralis group of Streptococci and increased arginine metabolizers, which improved pH.
“Overall, arginine made the biofilms less harmful by reducing their acidity, altering their carbohydrate structure, and reshaping the microbiome within them,” they wrote.
The researchers said future studies should explore the interplay between arginine treatment and biofilm architecture.
“Dental caries, being prevalent across all ages and regions, could be combated using strategies such as supplementation of arginine in toothpastes or oral rinses for people who are more susceptible to them. Arginine … could find application even in children,” the SciTech article states.
