title: Induction of cytotoxicity, oxidative stress and genotoxicity by root filling pastes used in primary teeth.
abstract: OBJECTIVE
  To evaluate the cytotoxicity, oxidative stress and genotoxicity in vitro of four iodoform pastes and three calcium hydroxide pastes.
  
  
  METHODS
  Peripheral blood mononuclear cells (PBMCs) and pure calf thymus DNA (dsDNA) were exposed to extracts of the pastes. Cytotoxicity was assessed with the MTT assay. Generation of reactive oxygen species (ROS) was evaluated using a DCFH-DA assay, and lipid peroxidation was evaluated using a TBARS assay. Genotoxicity was evaluated using the alkaline comet assay and Genomodifier capacity assay (GEMO). All tests were performed after 24 h and 72 h of cell exposure, except GEMO. After performing the Kolmogorov-Smirnov test, data were analysed by Kruskal-Wallis and Dunn's post-tests, and anova with Dunnett's post-test, with a significance level established at P < 0.05.
  
  
  RESULTS
  The MTT assay revealed that chlorhexidine, Maxitrol and neomycin sulphate + bacitracin pastes decreased cell viability after 24 h (P < 0.05). No group was associated with a significant decreased cell viability or lipid peroxidation after 72 h. Calcium hydroxide pastes increased the cell viability levels at both experimental times (P < 0.05). Lipid peroxidation was observed with the exposure of cells to calcium hydroxide pastes after 24 h (P < 0.05). Exposure to chlorhexidine, Guedes-Pinto and calcium hydroxide pastes resulted in a significant increase in ROS after 24 h (P < 0.05), whereas iodoform pastes and Calen thickened with zinc oxide significantly increased the ROS after 72 h (P < 0.05). The comet assay revealed that exposure of the PBMCs to iodoform pastes did not damage DNA at either period of time (P > 0.05). However, chlorhexidine paste caused DNA damage in dsDNA (P < 0.05). Calcium hydroxide pastes caused DNA damage in both tests (P < 0.05).
  
  
  CONCLUSIONS
  The pastes varied in their ability to induce cytotoxicity, genotoxicity and oxidative stress. In general, Guedes-Pinto, Maxitrol and neomycin sulphate + bacitracin pastes exhibited better biocompatibility in vitro.
authors.affiliation: Postgraduate Program in Dental Sciences, Federal University of Santa Maria (UFSM), Santa Maria, Brazil.
authors.forename: C W
authors.initials: CW
authors.lastname: Pires
authors.affiliation: Postgraduate Program in Dental Sciences, Federal University of Santa Maria (UFSM), Santa Maria, Brazil.
authors.forename: G
authors.initials: G
authors.lastname: Botton
authors.affiliation: Postgraduate Program in Biological Sciences, Federal University of Santa Maria (UFSM), Santa Maria, Brazil.
authors.forename: F C
authors.initials: FC
authors.lastname: Cadoná
authors.affiliation: Postgraduate Program in Pharmacology, Federal University of Santa Maria (UFSM), Santa Maria, Brazil.
authors.forename: A K
authors.initials: AK
authors.lastname: Machado
authors.affiliation: Postgraduate Program in Pharmacology, Federal University of Santa Maria (UFSM), Santa Maria, Brazil.
authors.forename: V F
authors.initials: VF
authors.lastname: Azzolin
authors.affiliation: Department of Morphology, Federal University of Santa Maria (UFSM), Santa Maria, Brazil.
authors.forename: I B M
authors.initials: IB
authors.lastname: da Cruz
authors.affiliation: Biomedicine Course, Franciscan University Center (UNIFRA), Santa Maria, Brazil.
authors.forename: M R
authors.initials: MR
authors.lastname: Sagrillo
authors.affiliation: Department of Stomatology, Federal University of Santa Maria (UFSM), Santa Maria, Brazil.
authors.forename: J R
authors.initials: JR
authors.lastname: Praetzel
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002417:Cattle; D004247:DNA / Q000187:drug effects*; D004249:DNA Damage; D006801:Humans; D006847:Hydrocarbons, Iodinated / Q000494:pharmacology*; D007963:Leukocytes, Mononuclear / Q000187:drug effects* / Q000378:metabolism; D008422:Materials Testing; D018384:Oxidative Stress / Q000187:drug effects*; D017382:Reactive Oxygen Species / Q000378:metabolism; D012387:Root Canal Filling Materials / Q000494:pharmacology*; D018709:Statistics, Nonparametric; D014094:Tooth, Deciduous; D018675:Toxicity Tests
chemical_list: D006847:Hydrocarbons, Iodinated; D017382:Reactive Oxygen Species; D012387:Root Canal Filling Materials; D004247:DNA; C010473:iodoform
keywords: biocompatibility; calcium hydroxide; deciduous tooth; iodoform; pulpectomy; root canal filling materials