Effect of different activations of silver nanoparticle irrigants on the elimination of Enterococcus faecalis.

OBJECTIVES: This study aimed to compare the efficacy of silver nanoparticles (AgNPs) irrigating solution alone and following activation with photon-induced photoacoustic streaming (PIPS), photodynamic therapy (PDT) with indocyanine green (ICG), passive ultrasonic irrigation (PUI), and manual dynamic activation (MDA) method for elimination of Enterococcus faecalis (E. faecalis) from the root canal system. MATERIALS AND METHODS: A total of 59 extracted human single-rooted teeth were collected and prepared. E. faecalis was inoculated into the root canals and incubated for 4 weeks. The teeth were then randomly divided into five experimental groups (n = 10): the AN group, irrigation with AgNPs alone; the AN/ICG/DL group, irrigation with AgNPs and ICG, then activation with diode laser; the AN/PIPS group, irrigation with AgNPs and activation with 0.3 W Er: YAG laser; the AN/MDA group, irrigation with AgNPs and activation with tapered gutta-percha; and the AN/PUI group, irrigation with AgNPs and activation with ultrasonic. Also, two control groups of irrigation with 2.5% sodium hypochlorite (n = 5) and no intervention (n = 4) were also used. Samples were collected from the dentinal chips before and after the intervention, and the percentage of reduction in colony count was calculated. RESULTS: A significant reduction in E. faecalis colony count was noted in all groups (P < 0.05). Maximum reduction in colony count was noted in AN/PIPS and AN/PUI groups by 91.03 and 91.29%, respectively. Minimum reduction was noted in the AN group alone. CONCLUSION: Activation with PUI and PIPS enhanced the efficacy of AgNPs irrigating solution for elimination of E. faecalis from the root canal system. CLINICAL RELEVANCE: AgNPs activated by ultrasound or PIPS can be used as an adjunct for disinfection of the root canal system in endodontic treatment.

Evaluation of antimicrobial photodynamic therapy with toluidine blue against Enterococcus faecalis: Laser vs LED.

AIM: This study aimed to compare the antibacterial effect of antimicrobial photodynamic therapy (aPDT) by use of light emitting diode (LED) and diode laser light sources with toluidine blue (TBO) photosensitizer on Enterococcus faecalis (E. faecalis) biofilm in root canals of extracted single-canal human teeth. METHODS: Eighty-five sound human single-canal teeth were chosen for this study and standardized to have 15 mm of root length. The root canals were prepared with ProTaper rotary files and inoculated and incubated with E. faecalis for one week. Samples were divided into five experimental (n = 15) groups of PDT with TBO/LED, TBO/diode laser, LED, TBO and diode laser and one negative (NaOCl) and one positive (no treatment) control group. Dentin chip samples were collected from inside the canals using size 40 hedstrom file. The number of colony forming units (CFUs) in each group was calculated. RESULTS: Irrespective of the light source used for activation of photosensitizer (diode or LED), PDT was significantly more effective than other experimental groups (P < 0.001). No significant difference was noted between aPDT with diode laser or LED (P > 0.05). No significant difference was noted in colony count among other groups (LED, TBO, diode; P > 0.05). CONCLUSION: The results showed that aPDT significantly decreased residual bacteria in the canal. Thus, it may be used as an adjunct for root canal disinfection. Both diode and LED are suitable light sources for this purpose and can be used alternatively.