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Effect of dentin treatment on proliferation and differentiation of human dental pulp stem cells
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Minjeong Park, Nan-Sim Pang, Il-Young Jung
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Restor Dent Endod 2015;40(4):290-298. Published online September 23, 2015
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DOI: https://doi.org/10.5395/rde.2015.40.4.290
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Abstract
PDFPubReaderePub
- Objectives
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). Materials and MethodsDPSCs 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. ResultsDPSCs 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. ConclusionsThe application of Ca[OH]2 and additional treatment such as EDTA or instrumentation promoted the attachment and differentiation of DPSCs after NaOCl treatment.
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Assessment of sterilization effect and the alteration of surface texture and physical properties of gutta-percha cone after short-term chemical disinfection
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Nan-Sim Pang, Il-Young Jung, Yoon-Jung Yu, Kee-Yeon Kum
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J Korean Acad Conserv Dent 2006;31(2):133-140. Published online March 31, 2006
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DOI: https://doi.org/10.5395/JKACD.2006.31.2.133
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Abstract
PDFPubReaderePub
The purposes of this study were firstly to identify the microbial species on gutta-percha (GP) cones exposed at clinics using polymerase chain reaction, and secondly to evaluate the short-term sterilization effect of three chemical disinfectants. It also evaluated the alteration of surface texture and physical properties of GP cones after 5-min soaking into three chemical disinfectants. 150 GP cones from two endodontic departments were randomly selected for microbial detection using PCR assay with universal primer. After inoculation on the sterilized GP cones with the same microorganism identified by PCR assay, they were soaked in three chemical disinfectants: 5% NaOCl, 2% Chlorhexidine, and ChloraPrep for 1, 5, 10, and 30 minutes. The sterilization effect was evaluated by turbidity and subculture. The change of surface textures using a scanning electron microscope and the tensile strength and elongation rate of the GP cones were measured using an Instron 5500 (Canton). Statistical analysis was performed.
Four bacterial species were detected in 29 GP cones (19.4%), and all the species belonged to the genus Staphylococcus. All chemical disinfectants were effective in sterilization with just 1 minute soaking. On the SEM picture of NaOCl-soaked GP cone, a cluster of cuboidal crystals was seen on the cone surface. The tensile strength of NaOCl-soaked group was significantly higher than the other groups (p < 0.05). Also, all disinfectants significantly increased the elongation rate of GP cones compared to the fresh GP cone (p < 0.05). Present data demonstrate that three chemical disinfectants are useful for rapid sterilization of GP cone just before obturation.
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