Targeting Biofilms With Nanotechnology: A Comparative Study of Silver and Selenium Nanoparticles

Introduction and aims: Silver fluoride is an effective topical agent for arresting early childhood caries. However, its use is somewhat limited by aesthetic concerns, particularly permanent tooth discolouration caused by the precipitation of ionic silver derivatives following application. Nanotechnology offers promising alternative antimicrobial formulations to overcome this limitation. This study evaluated the biofilm inhibition potential of 6 types of silver and selenium nanoparticles, capped with natural materials. Methods: Using microdilution assays, the minimum biofilm inhibitory concentration and percentage inhibition were measured on single- and dual-species biofilms of Streptococcus mutans and Candida albicans. Results: Silver nanoparticles, particularly those capped with casein and citrate, demonstrated superior biofilm inhibition, with concentrations of 28.7 and 121.6 µg/mL, achieving 91% and 94% inhibition, respectively. These results were comparable to the control of silver nitrate (31.3 µg/mL and 90% inhibition) and a commercial silver fluoride product, Riva Star Aqua (7.81 µg/mL and 94% inhibition). In contrast, selenium nanoparticles required high concentrations to achieve moderate efficacy. Conclusion: Silver nanoparticles showed significant biofilm inhibitory effects. Further investigations are warranted to evaluate their efficacy against complex multispecies oral biofilms and to determine their long-term stability.