title: Effects of root canal sealers on alkaline phosphatase in human osteoblastic cells.
abstract: BACKGROUND
  Histologic investigations have demonstrated that root canal sealers can induce mild to severe bone resorption. Alkaline phosphatase (ALP) is a membrane-bound glycoprotein, which is one of the osteogenic differentiation markers considered to indicate the formation of new bone. The aim of this study was to investigate the effects of an epoxy resin-based sealer AH26, a zinc oxide-eugenol-based sealer Canals, and a paste sealer N2 on the expression of ALP in human osteoblastic cell line U2OS cells.
  
  
  METHODS
  Freshly mixed materials were filled in glass rings and eluted in 10 mL of culture medium for 1 day. Subsequently, various dilutions (final dilution: 1/2, 1/4, and 1/8) of these extraction media were prepared for this study. Cytotoxicity was measured by the almar blue dye assay. Gene expression of ALP was examined by using reverse transcription-polymerase chain reaction. ALP activity was further evaluated by using substrate assay.
  
  
  RESULTS
  The results showed that AH26, Canals, and N2 were cytotoxic to U2OS cells in a concentration-dependent manner (P < .05). The exposure of U2OS cells to AH26 and N2 resulted in the down-regulation of ALP mRNA gene expression (P < .05). ALP activity was significantly suppressed by 3 root canal sealers (P < .05).
  
  
  CONCLUSIONS
  The inhibition of ALP expression might play an important role in the pathogenesis of root canal sealer-induced periapical bone destruction.
authors.affiliation: Department of Dentistry, Chung Shan Medical University Hospital, School of Dentistry, Chung Shan Medical University, Taichung, Taiwan.
authors.forename: Fu-Mei
authors.initials: FM
authors.lastname: Huang
authors.forename: Shun-Fa
authors.initials: SF
authors.lastname: Yang
authors.forename: Yu-Chao
authors.initials: YC
authors.lastname: Chang
mesh_terms: D000469:Alkaline Phosphatase / Q000037:antagonists & inhibitors / Q000187:drug effects*; D001729:Bismuth / Q000633:toxicity; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D004338:Drug Combinations; D004853:Epoxy Resins / Q000633:toxicity; D005054:Eugenol / Q000633:toxicity; D005557:Formaldehyde / Q000633:toxicity; D006801:Humans; D007202:Indicators and Reagents; D008422:Materials Testing; D010006:Osteoblasts / Q000187:drug effects* / Q000201:enzymology; D010078:Oxazines; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012387:Root Canal Filling Materials / Q000633:toxicity*; D012834:Silver / Q000633:toxicity; D014025:Titanium / Q000633:toxicity; D014966:Xanthenes; D015034:Zinc Oxide / Q000633:toxicity; D015035:Zinc Oxide-Eugenol Cement / Q000633:toxicity
chemical_list: D004338:Drug Combinations; D004853:Epoxy Resins; D007202:Indicators and Reagents; D010078:Oxazines; D012387:Root Canal Filling Materials; D014966:Xanthenes; D015035:Zinc Oxide-Eugenol Cement; C005843:resazurin; D005557:Formaldehyde; D012834:Silver; D005054:Eugenol; C028044:epoxy resin AH-26; C003799:N2 Dental Cement; D014025:Titanium; D000469:Alkaline Phosphatase; D015034:Zinc Oxide; D001729:Bismuth