AARHUS, Denmark: Recent research increasingly highlights the importance of ecology-based strategies in caries prevention. A new human clinical study has provided evidence that arginine, a naturally occurring amino acid, can influence dental biofilm development in a way that reduces its harmful potential and may help protect against caries. Conducted in patients with active caries, the study demonstrates that arginine alters biofilm acidity, structure and microbial composition in a manner that preserves biofilm ecology.