DNA double-strand breaks caused by new and contemporary endodontic sealers

Int Endod J. 2016 Dec;49(12):1141-1151. doi: 10.1111/iej.12577. Epub 2015 Dec 8.

Abstract

Aim: To investigate the cytotoxicity and genotoxicity of a new silicate-based BioRoot RCS® sealer in comparison with contemporary sealers.

Methodology: A periodontal ligament cell line using lentiviral gene transfer of human telomerase reverse transcriptase (hTERT) was used and exposed to subtoxic concentrations of 24-h eluates from two epoxy resin-based (AH Plus Jet® and Acroseal® ), four various methacrylate-based endodontic sealers (EndoREZ® , RealSeal® , RealSeal SE® and Hybrid Root SEAL® ) and three silicate-based sealers (BioRoot RCS® , iRootSP® and MTA Fillapex® ). The XTT-based cell viability assay was used for cytotoxicity screening of materials. The γ-H2AX assay was used for genotoxicity screening. In the γ-H2AX immunofluorescence assay, PDL-hTERT cells were exposed to eluates of the substances for 6 h and DNA double-strand breaks (DSB) were detected microscopically. Induced foci represented DSBs, which can induce ATM-dependent phosphorylation of the histone H2AX. The statistical significance of the differences between the experimental groups was compared using the Student's t-test (P < 0.05).

Results: The cytotoxicity of the 24-h eluates could be ranked in the following order: Hybrid Root SEAL® >RealSeal® >Acroseal® >RealSeal SE® ≥ AH Plus Jet® > EndoREZ® >MTA Fillapex® > iRoot SP® >BioRoot RCS® . In negative controls (cells which received medium only) 4.08 ± 0.53 DSB foci (mean ± SEM) whilst in positive controls 10.76 ± 4.05 DSB foci/cell were found. BioRoot RCS® and RealSeal SE® exhibited significant differences in foci formation at 1/3 EC50 compared with their 1/10 EC50 concentration (P < 0.05). Both concentrations (1/10 and 1/3 of EC50) of AH Plus Jet® , Acroseal® , RealSeal® and MTA Fillapex® sealers were not significantly different when compared with the medium control (P < 0.05).

Conclusions: New BioRoot RCS® was not toxic whilst Hybrid Root SEAL® demonstrated more toxicity and DNA double-strand breaks when compared with other resin- and silicate-based root canal sealers.

Keywords: DNA double-strand breaks; PDL-hTERT cells; cytotoxicity; eluates; sealers.

MeSH terms

  • Cell Line
  • Cell Survival / drug effects
  • Composite Resins / toxicity
  • DNA Breaks, Double-Stranded / drug effects*
  • Epoxy Resins / toxicity
  • Humans
  • Mutagenicity Tests
  • Periodontal Ligament / cytology
  • Periodontal Ligament / drug effects
  • Pit and Fissure Sealants / toxicity*
  • Root Canal Filling Materials / toxicity*

Substances

  • Acroseal
  • Composite Resins
  • EndoRez
  • Epoxy Resins
  • Pit and Fissure Sealants
  • Root Canal Filling Materials
  • epoxy resin-based root canal sealer