In vitro biocompatibility evaluation of a root canal filling material that expands on water sorption

Ashraf A. Eid, Sergey Y. Nikonov, Stephen Warwick Looney, Anthony Didato, Li Na Niu, Martin D. Levin, Frederick Rueggeberg, David Henry Pashley, Ikuya Watanabe, Franklin Chi Meng Tay

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11 Scopus citations

Abstract

Introduction: 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.

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Keywords

  • Alizarin red S
  • CPoint
  • MTT assay
  • alkaline phosphatase
  • biocompatibility
  • flow cytometry
  • qRT-PCR
  • vital cell staining

ASJC Scopus subject areas

  • Dentistry(all)

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