title: One-visit versus two-visit root canal treatment: effectiveness in the removal of endotoxins and cultivable bacteria.
abstract: BACKGROUND
  This clinical study was conducted to compare the effectiveness of 1-visit versus 2-visit root canal treatment in removing endotoxins and cultivable bacteria from primarily infected root canals.
  
  
  METHODS
  Forty-eight primarily infected root canals were selected and randomly divided into 4 groups: G1, 1% NaOCl; G2, 2% chlorhexidine (CHX) gel; G3, 1% NaOCl + Ca(OH)2; and G4, 2% CHX gel + Ca(OH)2 (all, n = 12). G1 and G2 involved 1-visit treatment, whereas G3 and G4 involved 2-visit treatment with the placement of Ca(OH)2 medication for 14 days. Samples were collected before and after root canal procedures. A chromogenic LAL assay test was used to quantify endotoxins. Culture techniques were used to determine bacterial counts.
  
  
  RESULTS
  Endotoxins and cultivable bacteria were detected in 100% of the initial samples. All treatment protocols were effective in reducing bacterial load from infected root canals: G1 (1% NaOCl, 99.97%), G2 (2% CHX gel, 99.75%), G3 (1% NaOCl + Ca(OH)2, 99.90%), and G4 (2% CHX gel + Ca(OH)2, 96.81%), respectively (P < .05). No differences were found in bacterial load reduction when comparing 1-visit and 2-visit treatment groups, irrespective of the irrigant tested (P > .05). Higher median percentage values of endotoxin reduction were achieved in the 2-visit treatment groups (G3, 98.01% and G4, 96.81%) compared with 1-visit treatment groups (G1, 86.33% and G2, 84.77%) (all P < .05).
  
  
  CONCLUSIONS
  Both 1-visit and 2-visit root canal treatment protocols were effective in reducing bacteria and endotoxins, but they were not able to eliminate them in all root canals analyzed. Furthermore, 2-visit root canal treatment protocols were more effective in reducing endotoxins than 1-visit root canal treatment protocols.
authors.affiliation: Department of Restorative Dentistry, Endodontic Division-UNESP-UNIV Estadual Paulista, São José dos Campos Dental School, São José dos Campos, São Paulo, Brazil.
authors.forename: Ana Claudia C
authors.initials: AC
authors.lastname: Xavier
authors.forename: Frederico C
authors.initials: FC
authors.lastname: Martinho
authors.forename: Adriana
authors.initials: A
authors.lastname: Chung
authors.forename: Luciane D
authors.initials: LD
authors.lastname: Oliveira
authors.forename: Antônio O C
authors.initials: AO
authors.lastname: Jorge
authors.forename: Márcia C
authors.initials: MC
authors.lastname: Valera
authors.forename: Cláudio A T
authors.initials: CA
authors.lastname: Carvalho
mesh_terms: D000891:Anti-Infective Agents, Local / Q000627:therapeutic use; D001071:Appointments and Schedules; D001419:Bacteria / Q000187:drug effects; D058491:Bacterial Load; D001431:Bacteriological Techniques; D002126:Calcium Hydroxide / Q000627:therapeutic use; D002710:Chlorhexidine / Q000627:therapeutic use; D002863:Chromogenic Compounds; D003786:Dental Pulp Cavity / Q000187:drug effects* / Q000382:microbiology; D004731:Endotoxins / Q000032:analysis*; D006801:Humans; D008033:Limulus Test; D012388:Root Canal Irrigants / Q000627:therapeutic use*; D018915:Root Canal Preparation / Q000295:instrumentation / Q000379:methods; D012390:Root Canal Therapy / Q000379:methods*; D012973:Sodium Hypochlorite / Q000627:therapeutic use; D016896:Treatment Outcome
chemical_list: D000891:Anti-Infective Agents, Local; D002863:Chromogenic Compounds; D004731:Endotoxins; D012388:Root Canal Irrigants; D012973:Sodium Hypochlorite; D002126:Calcium Hydroxide; D002710:Chlorhexidine
keywords: Endotoxin; LAL; limulus amebocyte lysate assay; root canal