title: Effect of immediate and delayed post space preparation on coronal bacterial microleakage in teeth obturated with a methacrylate-based sealer with and without accelerator.
abstract: OBJECTIVE
  To investigate the sealing properties of root fillings with resin-coated gutta-percha cones and a methacrylate-based resin endodontic sealer with and without an accelerator component in root canals subjected to immediate or delayed post space preparation.
  
  
  METHODS
  Forty-eight extracted human teeth with single straight root canals were treated endodontically. Specimens were then assigned to four groups of 10 teeth each (n=10). After autoclaving, the following operative procedures were carried out under strict aseptic conditions. In Group 1 the root canals were filled with resin-coated gutta-percha cones and a methacrylate based resin endodontic sealer (EndoREZ). Post space preparations were performed 2 minutes after the sealer had set. In Group 2 the root canals were filled as in Group 1 but with the addition of a chemical accelerator. The post space preparations were also performed 2 minutes after the sealer had set. Groups 3 and 4 were filled as in Groups 1 and 2 respectively, however the post space preparations were done 7 days after the root canal filling was completed. One positive and one negative control tooth per group was added. All specimens were subjected to a coronal bacterial leakage of E. faecalis during a 60-day period using a dual chamber microbial leakage model. Data was analyzed among groups with the Kaplan-Meier survival analysis while significant pairwise differences were analyzed with the log-rank test (P<0.05).
  
  
  RESULTS
  No significant differences (P>0.05) in bacterial leakage were observed between Groups 1 and 2 and between Groups 3 and 4. However, Groups 1 and 2 differed significantly from Groups 3 and 4 (P<0.05).
authors.affiliation: Faculty of Medicine, School of Dentistry, University of El Salvador/AOA, Buenos Aires, Argentina.
authors.forename: Osvaldo
authors.initials: O
authors.lastname: Zmener
authors.forename: Cornelis H
authors.initials: CH
authors.lastname: Pameijer
authors.forename: Susana
authors.initials: S
authors.lastname: Alvarez Serrano
mesh_terms: D003188:Composite Resins; D003763:Dental Leakage / Q000382:microbiology / Q000517:prevention & control*; D013293:Enterococcus faecalis; D006171:Gutta-Percha; D006801:Humans; D053208:Kaplan-Meier Estimate; D044367:Phase Transition; D011176:Post and Core Technique; D012387:Root Canal Filling Materials; D012389:Root Canal Obturation / Q000379:methods*; D013997:Time Factors
chemical_list: D003188:Composite Resins; C481259:EndoRez; D012387:Root Canal Filling Materials; D006171:Gutta-Percha