title: Zinc Oxide Nanoparticles Enhance Physicochemical Characteristics of Grossman Sealer.
abstract: BACKGROUND
  Metallic antibacterial nanoparticles have been shown to provide distinct antibacterial advantage and antibiofilm efficacy when applied in infected root canals. The purpose of this study was to evaluate the influence of incorporating zinc oxide nanoparticles (ZnO-Np) on the physicochemical properties of Grossman sealer.
  
  
  METHODS
  Grossman sealer was prepared according to its original formula. Additionally, 4 experimental sealers were prepared by replacing the zinc oxide component of the powder with ZnO-Np (average size of 20 nm) in different amounts (25%, 50%, 75%, and 100%). Characterization of the setting time, flow, solubility, dimensional changes, and radiopacity were performed according to American National Standards Institute (ANSI)/American Dental Association (ADA) Specification 57. Scanning electron microscopic and energy-dispersive X-ray spectroscopic analyses were conducted to assess the ultrastructural and chemical characteristics of experimental sealers subjected to the solubility test. Statistical analyses were performed with analysis of variance and post hoc Tukey-Kramer tests with a significance level of 5%.
  
  
  RESULTS
  A statistically significant difference in the setting time was observed among groups (P < .05), but only 25% ZnO-Np sealer complied with ANSI/ADA requirements. There was a significant difference in the flow characteristics between the control and 25% and 75% ZnO-Np experimental sealers (P < .05), but all sealers conformed to ANSI/ADA standardization; 25% ZnO-Np sealer showed significantly less solubility (1.81% ± 0.31%) and dimensional change (-0.34% ± 0.12%) than other sealers (P < .05). All sealers showed ultrastructural changes with increasing solubility.
  
  
  CONCLUSIONS
  ZnO-Np decreased the setting time and dimensional changes characteristic of Grossman sealer; 25% ZnO-Np improved the physicochemical properties of Grossman sealer in accordance with ANSI/ADA requirements.
authors: Department of Restorative Dentistry, Faculty of Dentistry, University of São Paulo, Ribeirão Preto, Brazil. Electronic address: marcoversiani@yahoo.com.
authors: Marco Aurélio
authors: MA
authors: Versiani
authors: Department of Endodontics, Faculty of Dentistry, University of Ribeirão Preto, Ribeirão Preto, Brazil.
authors: Fuad Jacob
authors: FJ
authors: Abi Rached-Junior
authors: Department of Clinical Sciences, Faculty of Dentistry, University of Toronto, Toronto, Canada.
authors: Anil
authors: A
authors: Kishen
authors: Department of Restorative Dentistry, Faculty of Dentistry, University of São Paulo, Ribeirão Preto, Brazil.
authors: Jesus Djalma
authors: JD
authors: Pécora
authors: Department of Endodontics, Faculty of Dentistry, University of Ribeirão Preto, Ribeirão Preto, Brazil.
authors: Yara Terezinha
authors: YT
authors: Silva-Sousa
authors: Department of Restorative Dentistry, Faculty of Dentistry, University of São Paulo, Ribeirão Preto, Brazil.
authors: Manoel Damião
authors: MD
authors: de Sousa-Neto
mesh_terms: D000180:Acrylic Resins; D055598:Chemical Phenomena; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D053758:Nanoparticles / Q000737:chemistry*; D012387:Root Canal Filling Materials / Q000737:chemistry*; D012995:Solubility; D013499:Surface Properties; D013997:Time Factors; D015034:Zinc Oxide / Q000737:chemistry*; D015035:Zinc Oxide-Eugenol Cement / Q000737:chemistry*
chemical_list: D000180:Acrylic Resins; D012387:Root Canal Filling Materials; D015035:Zinc Oxide-Eugenol Cement; C045432:Grossman's sealer; C041289:Radio-Opaque acrylic resin; D015034:Zinc Oxide
keywords: Grossman sealer; nanoparticles; nanosized particles; physicochemical properties; root canal sealer; zinc oxide