Antibacterial effect of silver nanoparticles against Enterococcus faecalis

Abstract

Objective: This study aimed to investigate the bactericidal effect of silver nanoparticles (AgNPs) in reducing bacterial infection in root canal when used as intracanal medicament alone or in addition to the conventionally used calcium hydroxide (Ca(OH)2). Materials and Methods: The root canals of 110 single-rooted teeth were cleaned, shaped, and sterilized. All groups, except for negative control, were inoculated with Enterococcus faecalis for 48 h. Then, teeth were divided into five groups according to the intracanal medicaments to be used. Group I (n = 30): Ca(OH)2. Group II (n = 30): AgNP. Group III (n = 30): AgNP + Ca(OH)2. Group IV (n = 10) was used as a positive control where the root canals were inoculated with E. faecalis and left without treatment. Group V (n = 10) was used as a negative control where the root canals were checked for the absence of bacterial growth. Specimens were incubated for 1 and 2 weeks. Pre- and post-medication samples were obtained by paper points, and the colony-forming units were counted. Results: Ca(OH)2 resulted in a higher percentage of bacterial reduction in both 1 and 2 weeks of application (81.5% and 98%, respectively). AgNP was ineffective against E. faecalis with 32.9% bacterial reduction in 1 week and 56.5% after 2 weeks. Conclusion: It was concluded that the antibacterial effect of AgNP was lower than Ca(OH)2 or combination of both materials.