title: Proinflammatory Activity of Primarily Infected Endodontic Content against Macrophages after Different Phases of the Root Canal Therapy.
abstract: BACKGROUND
  This study investigated the presence of target bacterial species and the levels of endotoxins in teeth with apical periodontitis. Levels of inflammatory mediators (interleukin [IL]-1β and tumor necrosis factor [TNF]-α) were determined after macrophage stimulation with endodontic content after different phases of endodontic therapy using different irrigants.
  
  
  METHODS
  Thirty primarily infected root canals were randomly assigned into 3 groups according to the irrigant used for root canal preparation (n = 10 per group): GI: 2.5% sodium hypochlorite, GII: 2% chlorhexidine gel, and GIII (control group): saline solution. Root canal samples were taken by using paper points before (s1) and after root canal instrumentation (s2), subsequently to 17% EDTA (s3), after 30 days of intracanal medication (Ca[OH]2 + saline solution) (s4), and before root canal obturation (s5). Polymerase chain reaction (16S recombinant DNA) and limulus amebocyte lysate assay were used for bacterial and endotoxin detection, respectively. Macrophages were stimulated with the root canal contents for IL-1β/TNF-α measurement using enzyme-linked immunosorbent assay.
  
  
  RESULTS
  Porphyromonas gingivalis (17/30), Porphyromonas endodontalis (15/30), and Prevotella nigrescens (11/30) were the most prevalent bacterial species. At s1, endotoxins were detected in 100% of the root canals (median = 32.43 EU/mL). In parallel, substantial amounts of IL-1β and TNF-α were produced by endodontic content-stimulated macrophages. At s2, a significant reduction in endotoxin levels was observed in all groups, with GI presenting the greatest reduction (P < .05). After a root canal rinse with EDTA (s3), intracanal medication (s4), and before root canal obturation (s5), endotoxin levels reduced without differences between groups (P < .05). IL-1β and TNF-α release decreased proportionally to the levels of residual endotoxin (P < .05).
  
  
  CONCLUSIONS
  Regardless of the use of sodium hypochlorite or CHX, the greatest endotoxin reduction occurs after chemomechanical preparation. Increasing steps of root canal therapy associated with intracanal medication enhances endotoxin reduction, leading to a progressively lower activation of proinflammatory cells such as macrophages.
authors.affiliation: Department of Restorative Dentistry, Endodontics Division, Piracicaba Dental School, State University of Campinas, UNICAMP, Piracicaba, Brazil.
authors.forename: Ariane C S
authors.initials: AC
authors.lastname: Marinho
authors.affiliation: Department of Restorative Dentistry, Endodontics Division, Piracicaba Dental School, State University of Campinas, UNICAMP, Piracicaba, Brazil.
authors.forename: Frederico C
authors.initials: FC
authors.lastname: Martinho
authors.affiliation: Department of Semiology and Clinics, Periodontics Division, Pelotas School of Dentistry, Federal University of Pelotas (UFPel), Pelotas, Brazil.
authors.forename: Fábio R M
authors.initials: FR
authors.lastname: Leite
authors.affiliation: Graduate Program in Dentistry, Pelotas School of Dentistry, Federal University of Pelotas (UFPel), Pelotas, Brazil.
authors.forename: Gustavo G
authors.initials: GG
authors.lastname: Nascimento
authors.affiliation: Department of Restorative Dentistry, Endodontics Division, Piracicaba Dental School, State University of Campinas, UNICAMP, Piracicaba, Brazil. Electronic address: bpgomes@fop.unicamp.br.
authors.forename: Brenda P F A
authors.initials: BP
authors.lastname: Gomes
mesh_terms: D002710:Chlorhexidine / Q000627:therapeutic use; D006801:Humans; D053583:Interleukin-1beta / Q000032:analysis; D008070:Lipopolysaccharides / Q000032:analysis*; D008262:Macrophage Activation / Q000187:drug effects* / Q000276:immunology; D010485:Periapical Periodontitis / Q000276:immunology / Q000382:microbiology* / Q000628:therapy*; D045202:Porphyromonas endodontalis / Q000302:isolation & purification; D016966:Porphyromonas gingivalis / Q000302:isolation & purification; D045242:Prevotella nigrescens / Q000302:isolation & purification; D012388:Root Canal Irrigants / Q000627:therapeutic use*; D018915:Root Canal Preparation / Q000379:methods*; D012973:Sodium Hypochlorite / Q000627:therapeutic use; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis
chemical_list: D053583:Interleukin-1beta; D008070:Lipopolysaccharides; D012388:Root Canal Irrigants; D014409:Tumor Necrosis Factor-alpha; D012973:Sodium Hypochlorite; D002710:Chlorhexidine
keywords: Bacteria; chlorhexidine; cytokines; lipopolysaccharide; medication; sodium hypochlorite