title: Influence of working length and foraminal enlargement on foramen morphology and sealing ability.
abstract: OBJECTIVE
  The present study evaluated the influence of the working length and foraminal enlargement on the sealing ability and anatomy of the apical region of the root.
  
  
  METHODS
  Fifty-five roots were divided into three groups: G1, instrumentation 1 mm short of the major foramen; G2, instrumentation in the limit of the apical foramen; and G3, instrumentation 1 mm beyond the foramen. All groups were prepared using nickel-titanium rotary files and obturated with AH Plus and Gutta-percha. Photomicrographs were taken using a scanning electron microscopy (SEM) before instrumentation, after instrumentation with each file, and after root canal filling. Moreover, bacterial microleakage with Enterococcus faecalis was performed.
  
  
  RESULTS
  The results were analyzed using Mann-Whitney, Friedman, Kruskal-Wallis and Kaplan-Meier tests at a significance level of 5%. The cemental canal was uninstrumented in G1. No statistical differences regarding foramen deviation was observed when compared G2 and G3 (P > 0.05). SEM analysis showed that G2 and G3 resulted in good apical foramen obturation. Microleakage showed no statistically significant differences between all of the groups tested.
  
  
  CONCLUSIONS
  Under the conditions of this study, it can be concluded that foramen enlargement resulted in more apical deviation; however, no differences in bacterial microleakage was observed among the experimental groups.
authors.forename: Juliana Melo
authors.initials: JM
authors.lastname: Silva
authors.forename: Gustavo A
authors.initials: GA
authors.lastname: Brandão
authors.affiliation: Department of Endodontics, Grande de Rio University (UNIGRANRIO), RJ, Brazil.
authors.forename: Emmanuel João Nogueira Leal
authors.initials: EJ
authors.lastname: Silva
authors.forename: Alexandre Augusto
authors.initials: AA
authors.lastname: Zaia
mesh_terms: D003763:Dental Leakage / Q000517:prevention & control*; D003786:Dental Pulp Cavity; D013293:Enterococcus faecalis; D006171:Gutta-Percha; D006801:Humans; D012387:Root Canal Filling Materials; D012389:Root Canal Obturation; D018915:Root Canal Preparation
chemical_list: D012387:Root Canal Filling Materials; D006171:Gutta-Percha