Antimicrobial action of photodynamic therapy on Enterococcus faecalis biofilm using curing light, curcumin and riboflavin.

Abstract

The aim of this study was to assess the effect of antimicrobial photodynamic therapy (aPDT) with curcumin and riboflavin on three-week Enterococcus faecalis biofilm. At first the 15-mm root canals of 65 single rooted extracted human teeth (including maxillary incisors, mandibular and maxillary canines and mandibular premolars) were separated from the crown and were prepared with ProTaper instruments. After autoclave sterilisation, samples were inoculated with E.\xa0faecalis suspension, and incubated for three weeks. After ensuring biofilm formation by scanning electron microscopy (SEM) in two teeth, the remaining 63 teeth were randomly divided into seven groups (n\xa0=\xa09): aPDT\xa0+\xa0curcumin, aPDT\xa0+\xa0riboflavin, LED, curcumin, riboflavin, 5.25% NaOCl (positive control) and no intervention (negative control). For light source a LED unit with 390-480\xa0nm wavelength (peak of 460\xa0nm), power density of 1000\xa0±\xa0100 mW\xa0cm-2 and mean energy density of 60\xa0J\xa0cm-2 was used. The roots were horizontally sectioned into coronal, middle and apical thirds each with 5\xa0mm thicknesses. Dentin chips with equal weight (1\xa0±\xa00.005\xa0g) were collected from the root canal walls with Gates Glidden drills and were transferred into microtubes containing 1\xa0mL of sterile saline and vortexed for 30\xa0s. Next, 10 µL of the contents of each tube was serially diluted and eventually, 10 µL of each solution was cultured on BHI agar. The number of colony-forming units was determined. Data were analysed using the Kruskal-Wallis and Friedman tests. The colony reduction was not significantly different between NaOCl and either riboflavin\xa0+\xa0LED or Curcumin\xa0+\xa0LED. The 5.25% NaOCl group showed maximum reduction in colony count, compared with the negative control (P\xa0=\xa00.00). Groups with aPDT with Curcumin\xa0+\xa0LED (P\xa0=\xa00.005), and with riboflavin\xa0+\xa0LED (P\xa0=\xa00.011) showed significant reduction in colony count in all three canal thirds (P\xa0<\xa00.05) without any difference with one another. With significant reduction of E.\xa0faecalis colony count, aPDT with Curcumin and riboflavin can serve as an adjunct to routine root canal disinfection method.