Comparative Evaluation of Antimicrobial Efficacy of Sodium Hypochlorite, Silver Diamine Fluoride, Chitosan and Bioactive Glass Nanoparticles as Root Canal Irrigants against the Bacterial Strain of Enterococcus faecalis- An In vitro Study

Abstract

Introduction: Enterococcus faecalis (E. faecalis) is the most commonly encountered microorganism detected in persistent root canal infections. These bacteria possess certain virulence factors, invade dentinal tubules and resist nutritional deprivation. Proper irrigation is an essential step for success in root canal therapies which is achieved by using excellent endodontic irrigants. Aim: To evaluate the antimicrobial efficacy of Sodium Hypochlorite (NaOCl), Silver Diamine Fluoride (SDF), Chitosan Nanoparticles (CNPs) and Bioactive Glass Nanoparticles (BAGNP) as root canal irrigants against the bacterial strain of Enterococcus Faecalis (E. faecalis) using agar well diffusion method. Materials and Methods: In this in-vitro study, the test materials were manipulated in accordance with the manufacturer’s instructions. The antimicrobial properties of root canal irrigants were evaluated by using agar diffusion method using bacterial strain of Enterococcus faecalis (ATCC 29212). 0.25 mL of each irrigant was placed on to 6.5 mm diameter blotting papers which were placed in 7 mm diameter wells on the Mueller Hinton agar plates. Later, E. faecalis strains were inoculated with sterile cotton swab on to the agar plates. All the plates were incubated at 37°C and evaluated at 24, 48 and 72 hours after pre-diffusion of test materials for two hours at room temperature. A 0.5 mm precision ruler was used to measure the microbial inhibition zones and then the results were expressed as mean and standard deviation. The results were tabulated and analysed using One-way ANOVA to find out if there was a significant overall difference between the mean zones of inhibition of various irrigants and Post-hoc Tukey HSD test to find out where the differences occurred. The p-value <0.05 was considered as significant. Results: Sodium Hypochlorite showed the greatest zone of inhibition followed by SDF, Bioactive Glass Nanoparticles and Chitosan Nanoparticles respectively (p<0.0107). Mean zones of inhibition for Sodium Hypochlorite, SDF, Bioactive Glass Nanoparticles and Chitosan Nanoparticles were 11.6 mm, 6.6 mm, 5 mm, and 1.4 mm, respectively. There were no observable differences on 24, 48 and 72 hours. Conclusion: Sodium Hypochlorite was the most effective root canal irrigant followed by SDF and Bioactive Glass Nanoparticle whereas Chitosan Nanoparticles was the least efficacious compared to the rest against Enterococcus Faecalis.

Keywords

• disc diffusion
• endodontics
• re-infection
• zone of inhibition