title: Concentration-dependent effect of sodium hypochlorite on stem cells of apical papilla survival and differentiation.
abstract: BACKGROUND
  Intracanal disinfection is a crucial step in regenerative endodontic procedures. Most published cases suggest the use of sodium hypochlorite (NaOCl) as the primary irrigant. However, the effect of clinically used concentrations of NaOCl on the survival and differentiation of stem cells is largely unknown. In this study, we tested the effect of various concentrations of NaOCl on the stem cells of the apical papilla (SCAPs) survival and dentin sialophosphoprotein (DSPP) expression.
  
  
  METHODS
  Standardized root canals were created in extracted human teeth and irrigated with NaOCl (0.5%, 1.5%, 3%, or 6%) followed by 17% EDTA or sterile saline. SCAPs in a hyaluronic acid-based scaffold were seeded into the canals and cultured for 7 days. Next, viable cells were quantified using a luminescence assay, and DSPP expression was evaluated using quantitative real-time polymerase chain reaction.
  
  
  RESULTS
  There was a significant reduction in survival and DSPP expression in the group treated with 6% NaOCl compared with the untreated control group. Comparable survival was observed in the groups treated with the lower concentrations of NaOCl, but greater DSPP expression was observed in the 1.5% NaOCl group. In addition, 17% EDTA resulted in increased survival and DSPP expression partially reversing the deleterious effects of NaOCl.
  
  
  CONCLUSIONS
  Collectively, the results suggest that dentin conditioning with high concentrations of NaOCl has a profound negative effect on the survival and differentiation of SCAPs. However, this effect can be prevented with the use of 1.5% NaOCl followed by 17% EDTA. The inclusion of this irrigation regimen might be beneficial in regenerative endodontic procedures.
authors: Department of Endodontics, University of Texas Health Science Center at San Antonio, Texas.
authors: David E
authors: DE
authors: Martin
authors: Department of Restorative Dentistry, Piracicaba School of Dentistry, State University of Campinas, São Paulo, Brazil.
authors: Jose Flavio A
authors: JF
authors: De Almeida
authors: Department of Endodontics, University of Texas Health Science Center at San Antonio, Texas.
authors: Michael A
authors: MA
authors: Henry
authors: Department of Biomedical Engineering, University of Texas, Austin, Texas.
authors: Zin Z
authors: ZZ
authors: Khaing
authors: Department of Biomedical Engineering, University of Texas, Austin, Texas.
authors: Christine E
authors: CE
authors: Schmidt
authors: Department of Endodontics, University of Texas Health Science Center at San Antonio, Texas.
authors: Fabricio B
authors: FB
authors: Teixeira
authors: Department of Endodontics, University of Texas Health Science Center at San Antonio, Texas. Electronic address: Diogenes@uthscsa.edu.
authors: Anibal
authors: A
authors: Diogenes
mesh_terms: D018929:Cell Culture Techniques; D002454:Cell Differentiation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D003771:Dental Papilla / Q000166:cytology; D003804:Dentin / Q000166:cytology; D004305:Dose-Response Relationship, Drug; D004492:Edetic Acid / Q000627:therapeutic use; D016326:Extracellular Matrix Proteins / Q000032:analysis / Q000187:drug effects; D006801:Humans; D006820:Hyaluronic Acid / Q000737:chemistry; D049408:Luminescent Agents; D009804:Odontoblasts / Q000187:drug effects; D010750:Phosphoproteins / Q000032:analysis / Q000187:drug effects; D012388:Root Canal Irrigants / Q000008:administration & dosage / Q000494:pharmacology*; D012795:Sialoglycoproteins / Q000032:analysis / Q000187:drug effects; D012973:Sodium Hypochlorite / Q000008:administration & dosage / Q000494:pharmacology*; D013234:Stem Cells / Q000187:drug effects*; D023822:Tissue Engineering / Q000379:methods; D054457:Tissue Scaffolds / Q000737:chemistry; D019227:Tooth Apex / Q000166:cytology; D000099311:Dentin Sialophosphoprotein
chemical_list: D004492:Edetic Acid; D016326:Extracellular Matrix Proteins; D006820:Hyaluronic Acid; D049408:Luminescent Agents; D010750:Phosphoproteins; D012388:Root Canal Irrigants; D012795:Sialoglycoproteins; D012973:Sodium Hypochlorite; D000099311:Dentin Sialophosphoprotein
keywords: Dentin conditioning; EDTA; dentin sialophosphoprotein; gene expression; irrigant; regenerative endodontics; sodium hypochlorite; stem cells of apical papilla; survival; viability