title: Synthesis and characterization of zinc oxide nanocrystals and histologic evaluation of their biocompatibility by means of intraosseous implants.
abstract: OBJECTIVE
  To synthesize and characterize zinc oxide (ZnO) nanocrystals and assess their biological properties for applications in dentistry, particularly in endodontics, by means of intraosseous implants.
  
  
  METHODS
  ZnO nanocrystals were synthesized and characterized by micro-Raman spectroscopy and X-ray Diffraction. Ten guinea pigs were divided into two groups representing experimental periods of 4 and 12 weeks and received implants on both sides of the mandible in the region of the symphysis. The connective tissue response along the lateral wall outside the cup served as the negative control. The animals were euthanized at the end of each observation period and prepared for routine histological examinations which evaluated inflammatory response and material biocompatibility.
  
  
  RESULTS
  ZnO nanocrystals were highly pure, crystalline, and averaged 21 nm in size. After 12 weeks, tissue analysis revealed the presence of a thin layer of connective tissue with some giant cells between the implanted material and underlying bone tissue. While signs of mild inflammation could be seen, bone resorption and remodeling were not apparent.
  
  
  CONCLUSIONS
  ZnO nanocrystals were biocompatible, well tolerated and allowed new bone formation and bone remodelling.
authors.affiliation: Department of Endodontics, School of Dentistry, Uberlandia, MG, Brazil.
authors.forename: C J A
authors.initials: CJ
authors.lastname: Sousa
authors.forename: M C
authors.initials: MC
authors.lastname: Pereira
authors.forename: R J
authors.initials: RJ
authors.lastname: Almeida
authors.forename: A M
authors.initials: AM
authors.lastname: Loyola
authors.forename: A C A
authors.initials: AC
authors.lastname: Silva
authors.forename: N O
authors.initials: NO
authors.lastname: Dantas
mesh_terms: D001672:Biocompatible Materials; D018360:Crystallography, X-Ray; D003758:Dental Implantation, Endosseous; D053758:Nanoparticles / Q000737:chemistry*; D013059:Spectrum Analysis, Raman; D015034:Zinc Oxide / Q000737:chemistry*
chemical_list: D001672:Biocompatible Materials; D015034:Zinc Oxide
keywords: ZnO; ZnO nanocrystals; biocompatibility; dental implants; endodontics; nanotechnology