title: Effect of dentin treatment on proliferation and differentiation of human dental pulp stem cells.
abstract: OBJECTIVE
  Sodium hypochlorite (NaOCl) is an excellent bactericidal agent, but it is detrimental to stem cell survival, whereas intracanal medicaments such as calcium hydroxide (Ca[OH]2) promote the survival and proliferation of stem cells. This study evaluated the effect of sequential NaOCl and Ca[OH]2 application on the attachment and differentiation of dental pulp stem cells (DPSCs).
  
  
  METHODS
  DPSCs were obtained from human third molars. All dentin specimens were treated with 5.25% NaOCl for 30 min. DPSCs were seeded on the dentin specimens and processed with additional 1 mg/mL Ca[OH]2, 17% ethylenediaminetetraacetic acid (EDTA) treatment, file instrumentation, or a combination of these methods. After 7 day of culture, we examined DPSC morphology using scanning electron microscopy and determined the cell survival rate with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. We measured cell adhesion gene expression levels after 4 day of culture and odontogenic differentiation gene expression levels after 4 wk using quantitative real-time polymerase chain reaction.
  
  
  RESULTS
  DPSCs did not attach to the dentin in the NaOCl-treated group. The gene expression levels of fibronectin-1 and secreted phosphoprotein-1 gene in both the Ca[OH]2- and the EDTA-treated groups were significantly higher than those in the other groups. All Ca[OH]2-treated groups showed higher expression levels of dentin matrix protein-1 than that of the control. The dentin sialophosphoprotein level was significantly higher in the groups treated with both Ca[OH]2 and EDTA.
  
  
  CONCLUSIONS
  The application of Ca[OH]2 and additional treatment such as EDTA or instrumentation promoted the attachment and differentiation of DPSCs after NaOCl treatment.
authors.affiliation: Department of Conservative Dentistry, Yonsei University College of Dentistry, Seoul, Korea.
authors.forename: Minjeong
authors.initials: M
authors.lastname: Park
authors.affiliation: Department of Advanced General Dentistry, Oral Science Research Center, Yonsei University College of Dentistry, Seoul, Korea.
authors.forename: Nan-Sim
authors.initials: NS
authors.lastname: Pang
authors.affiliation: Department of Conservative Dentistry, Yonsei University College of Dentistry, Seoul, Korea.
authors.forename: Il-Young
authors.initials: IY
authors.lastname: Jung
keywords: Calcium hydroxide; Cell attachment; Cell differentiation; Dental pulp stem cells; Regenerative endodontics; Sodium hypochlorite