title: Vitality of Enterococcus faecalis inside dentinal tubules after five root canal disinfection methods.
abstract: OBJECTIVE
  To compare the vitality of Enterococcus faecalis within dentinal tubules after subjected to five root canal disinfection methods.
  
  
  METHODS
  Dentin blocks (n = 60) were colonized with E. faecalis. After 4 weeks of incubation, the dentin blocks were divided into one control and five test groups (n = 10 each). The root canals of test groups were subjected to one of the disinfection methods, namely, normal saline (NS), sodium hypochlorite (NaOCl), chlorhexidine digluconate (CHX), neodymium-doped yttrium aluminum garnet (Nd: YAG) laser, and diode laser. The effect of disinfection methods was assessed by LIVE/DEAD BacLight stain under the confocal laser scanning microscopy to determine the "zone of dead bacteria" (ZDB). Mean values were calculated for ZDB and the difference between groups was established.
  
  
  RESULTS
  Penetration of E. faecalis was seen to a depth of >1000 μm. Viable bacteria were detected with NS irrigation. NaOCl and CHX showed partial ZDB. When the root canals were disinfected with Nd: YAG and diode lasers, no viable bacteria were found.
  
  
  CONCLUSIONS
  E. faecalis has the ability to colonize inside dentinal tubules to a depth of >1000 μm. In contrast to conventional irrigants, both Nd: YAG and diode lasers were effective in eliminating the vitality of E. faecalis. NS, NaOCl, and CHX showed viable bacteria remaining in dentinal tubules.
authors.affiliation: Department of Endodontics, M.A. Rangoonwala Dental College and Hospital, Pune, Maharashtra, India.
authors.forename: Niranjan Ashok
authors.initials: NA
authors.lastname: Vatkar
authors.affiliation: Department of Endodontics, M.A. Rangoonwala Dental College and Hospital, Pune, Maharashtra, India.
authors.forename: Vivek
authors.initials: V
authors.lastname: Hegde
authors.affiliation: Department of Endodontics, M.A. Rangoonwala Dental College and Hospital, Pune, Maharashtra, India.
authors.forename: Sucheta
authors.initials: S
authors.lastname: Sathe
keywords: Chlorhexidine digluconate; Enterococcus faecalis; confocal laser scanning microscopy; neodymium-doped yttrium aluminum garnet laser and diode laser; normal saline; sodium hypochlorite