title: Effect of Er:YAG laser-activated irrigation solution on Enterococcus Faecalis biofilm in an ex-vivo root canal model.
abstract: Abstract Objective: The purpose of this study was to evaluate mineral content and surface morphology of root canals coated with Enterococcus faecalis biofilm after treatment with several endodontic irrigation solutions, with and without Er:YAG laser-activated irrigation (LAI).
  
  
  BACKGROUND
  LAI has been introduced as a powerful method for root canal irrigation resulting in smear-layer removal from the root canal wall.
  
  
  METHODS
  Distal and palatal roots from 60 freshly extracted human molars were used in this study. The coronal of each tooth was removed. Roots were split longitudinally and placed in an ultrasonic bath to remove the smear layer, creating conditions for the formation of E. faecalis biofilm. After incubation, the two halves were reassembled in impression material to simulate clinical conditions. Specimens were divided into two main groups: roots rinsed with irrigation solutions and roots subjected to laser irradiation combined with irrigation solutions. Solutions tested were 2% chlorhexidine and 17% ethylenediaminetetraacetic acid (EDTA) and saline.
  
  
  RESULTS
  Surface morphology: 17% EDTA irrigant solution combined with Er:YAG laser showed the best results for removing bacteria from the root canal walls. Chemical analysis: all samples treated with combined laser irradiation and irrigation solution had low surface levels of Ca compared with samples treated with irrigation alone. The Ca/P ratio was highest in the laser-EDTA group. Overall, mineral changes caused by laser with irrigation solutions were minimal, and statistically nonsignificant.
  
  
  CONCLUSIONS
  In vitro irrigation solutions, combined with Er:YAG laser irradiation, were effective in removing E. faecalis biofilm from root canal walls. Irrigation solutions without laser irradiation were less effective, leaving a layer of biofilm on the dentin surface.
authors.affiliation: Department of Endodontics, Faculty of Dental Medicine, Hebrew University-Hadassah, Jerusalem, Israel. helft1@bezeqint.net
authors.forename: Sharonit
authors.initials: S
authors.lastname: Sahar-Helft
authors.forename: Adam
authors.initials: A
authors.lastname: Stabholtz
authors.forename: Joshua
authors.initials: J
authors.lastname: Moshonov
authors.forename: Vitaly
authors.initials: V
authors.lastname: Gutkin
authors.forename: Idan
authors.initials: I
authors.lastname: Redenski
authors.forename: Doron
authors.initials: D
authors.lastname: Steinberg
mesh_terms: D018441:Biofilms; D003786:Dental Pulp Cavity / Q000382:microbiology*; D013293:Enterococcus faecalis / Q000502:physiology*; D006801:Humans; D053844:Lasers, Solid-State; D012388:Root Canal Irrigants
chemical_list: D012388:Root Canal Irrigants