title: Dentin extends the antibacterial effect of endodontic sealers against Enterococcus faecalis biofilms.
abstract: BACKGROUND
  The purpose of this study was to evaluate the antimicrobial effects of root canal sealers on Enterococcus faecalis biofilms in dentinal tubules by using a novel dentin infection model.
  
  
  METHODS
  Cells of E. faecalis were introduced into the dentinal tubules by centrifugation and incubated in brain-heart infusion broth for 3 weeks. An equal thickness of AH Plus, Endosequence BC sealer (BC sealer), and pulp canal sealer EWT (PCEWT) was placed on the root canal wall of the dentin specimens for 1, 7, and 30 days in humid conditions at 37°C. Gutta-percha and water were used in a similar manner as the tested sealers. The proportions of dead and live bacteria inside the dentinal tubules after exposure to root canal sealers were assessed by confocal laser scanning microscopy.
  
  
  RESULTS
  Significantly more bacteria were killed in the 3 sealer groups than in the 2 control groups (P < .05). BC sealer and AH Plus resulted in significantly more dead cells than PCEWT did. There was no statistically significant difference between BC sealer and AH Plus at any time point (P > .05). Thirty days of exposure to BC sealer and AH Plus resulted in significantly more dead bacteria in dentin than 7-day and 1-day exposures in the biofilms, whereas no statistically significant increase of the proportion of dead bacteria was detected between 7-day and 30-day PCEWT (P > .05).
  
  
  CONCLUSIONS
  The 3 endodontic root canal sealers had antibacterial effects against E. faecalis in the dentinal tubules. BC sealer and AH Plus had superior antibacterial effects compared with PCEWT. The antibacterial effects of sealers in dentinal tubules continued after setting.
authors.affiliation: Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, Canada; The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, China.
authors.forename: Zhejun
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, Canada.
authors.forename: Ya
authors.initials: Y
authors.lastname: Shen
authors.affiliation: Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, Canada. Electronic address: markush@dentistry.ubc.ca.
authors.forename: Markus
authors.initials: M
authors.lastname: Haapasalo
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001431:Bacteriological Techniques; D018441:Biofilms / Q000187:drug effects*; D002130:Calcium Phosphates / Q000494:pharmacology; D003804:Dentin / Q000382:microbiology* / Q000648:ultrastructure; D004338:Drug Combinations; D013293:Enterococcus faecalis / Q000187:drug effects*; D004853:Epoxy Resins / Q000494:pharmacology; D006171:Gutta-Percha / Q000494:pharmacology; D006801:Humans; D006813:Humidity; D050296:Microbial Viability / Q000187:drug effects; D018613:Microscopy, Confocal; D010087:Oxides / Q000494:pharmacology; D011897:Random Allocation; D012387:Root Canal Filling Materials / Q000494:pharmacology*; D017640:Silicates / Q000494:pharmacology; D013997:Time Factors; D046509:Tissue Culture Techniques; D015035:Zinc Oxide-Eugenol Cement / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D002130:Calcium Phosphates; D004338:Drug Combinations; C550603:EndoSequence root repair material; D004853:Epoxy Resins; D010087:Oxides; D012387:Root Canal Filling Materials; D017640:Silicates; D015035:Zinc Oxide-Eugenol Cement; C534916:epoxy resin-based root canal sealer; D006171:Gutta-Percha
keywords: Confocal laser scanning microscopy; Enterococcus faecalis; dentin; disinfection; sealer