title: In Vitro biocompatibility evaluation of a root canal filling material that expands on water sorption.
abstract: BACKGROUND
  CPoint is a polymeric endodontic point that takes advantage of water-induced, non-isotropic radial expansion to adapt to canal irregularities. This study evaluated the effects of CPoint on the viability and mineralization potential of odontoblast-like cells.
  
  
  METHODS
  The biocompatibility of CPoint and commercially available gutta-percha points was evaluated by using a rat odontoblast-like cell line (MDPC-23). Cell viability was evaluated with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, flow cytometry, and confocal laser scanning microscopy. The mineralization potential of MDPC-23 cells, in the presence of the root-filling materials, was evaluated by examining the changes in osteogenic gene marker expression (quantitative real-time polymerase chain reaction), alkaline phosphatase activity, alizarin red S assay, and transmission electron microscopy.
  
  
  RESULTS
  CPoint showed higher initial cytotoxicity compared with gutta-percha and Teflon (P < .05), which became nonsignificant after 4 immersion cycles. Significant differences were also found between eluents from CPoint and gutta-percha at 1:1 concentration (P < .05) but not at 1:10 or 1:100 concentration. Both materials induced minimal apoptosis-induced alteration in plasma membrane permeability, as evidenced by flow cytometry and confocal laser scanning microscopy. Compared with the Teflon negative control, CPoint and gutta-percha groups showed up-regulation of most osteogenic gene markers except for dentin sialophosphoprotein, which was down-regulated. Alkaline phosphatase activity and alizarin red assay for CPoint and gutta-percha were both significantly higher than for Teflon but not significantly different from each other (P > .05). Transmission electron microscopy showed discrete nodular electron-dense mineralization foci in all 3 groups.
  
  
  CONCLUSIONS
  The in vitro biocompatibility of CPoint is comparable to gutta-percha with minimal adverse effects on osteogenesis after elution of potentially toxic components.
authors.affiliation: Department of Dental and Biomedical Material Sciences, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.
authors.forename: Ashraf A
authors.initials: AA
authors.lastname: Eid
authors.forename: Sergey Y
authors.initials: SY
authors.lastname: Nikonov
authors.forename: Stephen W
authors.initials: SW
authors.lastname: Looney
authors.forename: Anthony
authors.initials: A
authors.lastname: Didato
authors.forename: Li-na
authors.initials: LN
authors.lastname: Niu
authors.forename: Martin D
authors.initials: MD
authors.lastname: Levin
authors.forename: Frederick A
authors.initials: FA
authors.lastname: Rueggeberg
authors.forename: David H
authors.initials: DH
authors.lastname: Pashley
authors.forename: Ikuya
authors.initials: I
authors.lastname: Watanabe
authors.forename: Franklin R
authors.initials: FR
authors.lastname: Tay
mesh_terms: D000042:Absorption; D000180:Acrylic Resins / Q000737:chemistry* / Q000633:toxicity; D000181:Acrylonitrile / Q000737:chemistry / Q000633:toxicity; D000327:Adsorption; D000469:Alkaline Phosphatase / Q000187:drug effects; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001672:Biocompatible Materials / Q000737:chemistry* / Q000633:toxicity; D002113:Calcification, Physiologic / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D002463:Cell Membrane Permeability / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D016326:Extracellular Matrix Proteins / Q000187:drug effects; D006171:Gutta-Percha / Q000737:chemistry / Q000633:toxicity; D008422:Materials Testing; D046529:Microscopy, Electron, Transmission; D009757:Nylons / Q000737:chemistry* / Q000633:toxicity; D009804:Odontoblasts / Q000187:drug effects; D010012:Osteogenesis / Q000187:drug effects; D010750:Phosphoproteins / Q000187:drug effects; D011138:Polytetrafluoroethylene / Q000737:chemistry / Q000633:toxicity; D011145:Polyvinyls / Q000737:chemistry / Q000633:toxicity; D011760:Pyrrolidinones / Q000737:chemistry / Q000633:toxicity; D051381:Rats; D012387:Root Canal Filling Materials / Q000737:chemistry* / Q000633:toxicity; D012795:Sialoglycoproteins / Q000187:drug effects; D013499:Surface Properties; D015854:Up-Regulation; D014867:Water / Q000737:chemistry*; D000099311:Dentin Sialophosphoprotein
chemical_list: D000180:Acrylic Resins; D000181:Acrylonitrile; D000469:Alkaline Phosphatase; D001672:Biocompatible Materials; D016326:Extracellular Matrix Proteins; D006171:Gutta-Percha; D009757:Nylons; D010750:Phosphoproteins; D011138:Polytetrafluoroethylene; D011145:Polyvinyls; D011760:Pyrrolidinones; D012387:Root Canal Filling Materials; D012795:Sialoglycoproteins; D014867:Water; D000099311:Dentin Sialophosphoprotein; C000589422:CPoint