title: Cytotoxicity and genotoxicity of sodium percarbonate: a comparison with bleaching agents commonly used in discoloured pulpless teeth.
abstract: OBJECTIVE
  To evaluate the cytotoxicity and genotoxicity of sodium percarbonate (SPC) in comparison with bleaching agents used on discoloured pulpless teeth.
  
  
  METHODS
  The cytotoxicity and genotoxicity of bleaching agents were evaluated both in their pure form as well as at concentrations commonly used in clinical practice. Hydrogen peroxide (HP), carbamide peroxide (CP), sodium perborate (SP) and SPC were diluted in Dulbecco's modified Eagle's medium (DMEM) in series. To evaluate the cytotoxicity, the survival of 3T3/NIH mouse fibroblasts was measured photometrically using an 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay after a 24 h-exposure period. Genotoxicity was indicated by micronuclei (MN) formation, and modification of the normal cell was analysed by light microscopy (400x). Statistical analysis was performed by one-way anova, followed by a multiple-comparison Tukey post hoc test (P < 0.05).
  
  
  RESULTS
  All groups exhibited a dose-dependent cytotoxicity. However, CP showed a similar cytotoxic effect when compared with DMEM-untreated control (UC) group. HP and SPC were significantly more cytotoxic than SP. The genotoxicity test showed that SPC and SP had an intermediate rate of MN frequency when compared with the UC group. The mean rate of MN frequency for HP was higher and statistically more significant than for the other groups tested. No difference was observed when CP and UC groups were compared.
  
  
  CONCLUSIONS
  Sodium percarbonate showed cytotoxicity and genotoxicity similar to those of the other products tested. However, before SPC is used clinically, studies should be conducted to confirm its safety in vivo.
authors.affiliation: School of Dentistry, Institute of Biology, Federal University of Pelotas, Pelotas, RS, Brazil. raquelitafm@gmail.com
authors.forename: M R
authors.initials: MR
authors.lastname: Fernández
authors.forename: R V
authors.initials: RV
authors.lastname: Carvalho
authors.forename: F A
authors.initials: FA
authors.lastname: Ogliari
authors.forename: F A
authors.initials: FA
authors.lastname: Beira
authors.forename: A
authors.initials: A
authors.lastname: Etges
authors.forename: M
authors.initials: M
authors.lastname: Bueno
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001881:Borates / Q000633:toxicity; D000077463:Carbamide Peroxide; D002254:Carbonates / Q000633:toxicity*; D002460:Cell Line; D002470:Cell Survival; D003786:Dental Pulp Cavity / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004338:Drug Combinations; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects*; D006861:Hydrogen Peroxide / Q000633:toxicity; D051379:Mice; D015162:Micronucleus Tests; D016877:Oxidants / Q000633:toxicity; D010545:Peroxides / Q000633:toxicity*; D018709:Statistics, Nonparametric; D014073:Tooth Bleaching / Q000009:adverse effects* / Q000379:methods; D014075:Tooth Discoloration / Q000188:drug therapy; D019553:Tooth, Nonvital; D018675:Toxicity Tests; D014508:Urea / Q000031:analogs & derivatives / Q000633:toxicity
chemical_list: D001881:Borates; D002254:Carbonates; D004338:Drug Combinations; D016877:Oxidants; D010545:Peroxides; D000077463:Carbamide Peroxide; D014508:Urea; D006861:Hydrogen Peroxide; C027707:sodium perborate; C034738:sodium percarbonate