Biofilm modulatory response of arginine-fluoride varnish on multi-species biofilm

To examine the biofilm modulatory effect of arginine (Arg)-fluoride (F) varnish on multi-species biofilms. Experimental varnishes were prepared by incorporating L-Arg (1, 2, and 4%) in 5% NaF varnish, which served as the control. Multi-species biofilms comprising Streptococcus mutans, Streptococcus sanguinis and Streptococcus gordonii were grown on hydroxyapatite (HA) discs and treated with the Arg and F released from the experimental and control groups. The HA discs with treated biofilms were examined for biofilm composition. The biofilm thickness and live/dead counts were investigated using confocal microscopic imaging, while biofilm polysaccharides, proteins, and extracellular DNA (eDNA) were assessed spectrophotometrically. Bacterial composition in biofilms was analysed using viability real-time quantitative polymerase chain reaction (qPCR). The relative gene expression (RGE) was determined for gtfB, SMU.150, nlmD, arcA, and sagP. Both the 2 and 4% Arg-NaF groups reduced biofilm thickness, with the 4% Arg-NaF group showing a significantly greater proportion of dead bacteria, followed by 1 and 2% Arg-NaF (p