title: Influence of apical enlargement and complementary canal preparation with the Self-Adjusting File on endotoxin reduction in retreatment cases.
abstract: OBJECTIVE
  To compare the effectiveness of large apical preparations and complementary canal preparation with the Self-Adjusting File (SAF) in removing endotoxins from the root canal of teeth with apical periodontitis.
  
  
  METHODS
  Ten single-rooted and single-canaled teeth with post-treatment apical periodontitis were selected. Endotoxin samples were taken after removal of the root filling (S1), after chemomechanical preparation (CMP) using 2.5% NaOCl and an R25 file (S2), after CMP using 2.5% NaOCl and an R40 file (S3) and after complementary CMP using the SAF system (S4). Limulus amebocyte lysate (LAL) was used to measure endotoxin levels. The Friedman and Wilcoxon tests were used to compare endotoxin levels at each clinical intervention (P < 0.05).
  
  
  RESULTS
  After root filling removal, endotoxin was detected in 100% of the root canals (S1, 4.84 EU mL-1). CMP with the R25 file was able to significantly reduce endotoxin levels (P < 0.05). Increased levels of endotoxin removal were achieved by apical preparation with the R40 file (P < 0.05). Complementary CMP with SAF did not significantly reduce endotoxin levels (P > 0.05) following the use of the R40 instrument.
  
  
  CONCLUSIONS
  Apical enlargement protocols were effective in significantly reducing endotoxin levels. Complementary preparation with the SAF system failed to eliminate residual endotoxin contents beyond those obtained with the R40 instrument.
authors.affiliation: Department of Endodontics, School of Dentistry, Grande Rio University (UNIGRANRIO), Duque de Caxias, RJ, Brazil.
authors.forename: E J N L
authors.initials: EJNL
authors.lastname: Silva
authors.affiliation: Department of Endodontics, School of Dentistry, Grande Rio University (UNIGRANRIO), Duque de Caxias, RJ, Brazil.
authors.forename: V M
authors.initials: VM
authors.lastname: Ferreira
authors.affiliation: Department of Endodontics, School of Dentistry, Grande Rio University (UNIGRANRIO), Duque de Caxias, RJ, Brazil.
authors.forename: C C
authors.initials: CC
authors.lastname: Silva
authors.affiliation: Department of Endodontics, Campinas State University (UNICAMP), Piracicaba, SP, Brazil.
authors.forename: D R
authors.initials: DR
authors.lastname: Herrera
authors.affiliation: Department of Endodontics, School of Dentistry, Grande Rio University (UNIGRANRIO), Duque de Caxias, RJ, Brazil.
authors.forename: G
authors.initials: G
authors.lastname: De-Deus
authors.affiliation: Department of Endodontics, Campinas State University (UNICAMP), Piracicaba, SP, Brazil.
authors.forename: B P
authors.initials: BP
authors.lastname: Gomes
mesh_terms: D003762:Dental Instruments; D004731:Endotoxins / Q000032:analysis*; D006801:Humans; D010485:Periapical Periodontitis / Q000382:microbiology / Q000628:therapy*; D019233:Retreatment; D018915:Root Canal Preparation / Q000295:instrumentation*; D012973:Sodium Hypochlorite / Q000627:therapeutic use
chemical_list: D004731:Endotoxins; D012973:Sodium Hypochlorite
keywords: apical enlargement; endodontic retreatment; endotoxins; self-adjusting file