title: Histomorphometric evaluation of strontium-containing nanostructured hydroxyapatite as bone substitute in sheep.
abstract: The aim of this study is to evaluate the biocompatibility and osteoconductivity in surgical defects of sheep tibias filled with 1% strontium-containing nanostructured hydroxyapatite microspheres (SrHA), stoichiometric hydroxyapatite without strontium microspheres (HA), or blood clots. Santa Ines sheep were subjected to three perforations on the medial side of the left tibia. The biomaterials were characterized by X-ray Diffraction (XRD) and Fourier Transform Infrared (FTIR) before implantation and by X-Ray Microfluorescence (µFRX) and Scanning Electron Microscopy (SEM) after sheep tibias implantation. Surgical defects were filled with blood clots (control), SrHA (Group 1) or HA (Group 2). After 30 days, 5-µm bone blocks were obtained for histological evaluation, and the blocks obtained from 1 animal were embedded in methylmethacrylate for undecalcified sections. Mononuclear inflammatory infiltrate remained mild in all experimental groups. Giant cells were observed surrounding biomaterials particles of both groups and areas of bone formation were detected in close contact with biomaterials. All groups showed newly formed bone from the periphery to the center of the defects, which the control, HA and SrHA presented 36.4% (± 21.8), 31.2% (± 14.7) and 26.2% (± 12.9) of newly formed bone density, respectively, not presenting statistical differences. In addition, the connective tissue density did not show any significant between groups. The SrHA showing a higher volume density of biomaterial (51.2 ± 14.1) present in the defect compared to HA (32.6 ± 8.5) after 30 days (p = 0.03). Microspheres containing 1% SrHA or HA can be considered biocompatible, have osteoconductive properties and may be useful biomaterials for clinical applications.
authors.affiliation: School of Dentistry, Universidade Federal Fluminense, Niterói, RJ, Brazil.
authors.forename: Callinca Paolla Gomes
authors.initials: CP
authors.lastname: Machado
authors.affiliation: School of Dentistry, Universidade Federal Fluminense, Niterói, RJ, Brazil.
authors.forename: Suelen Cristina
authors.initials: SC
authors.lastname: Sartoretto
authors.affiliation: School of Dentistry, Universidade Federal Fluminense, Niterói, RJ, Brazil.
authors.forename: Adriana Terezinha Neves Novellino
authors.initials: AT
authors.lastname: Alves
authors.affiliation: Instituto Alberto Luiz Coimbra de Pós-Graduação e Pesquisa de Engenharia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
authors.forename: Inayá Barbosa Correa
authors.initials: IB
authors.lastname: Lima
authors.affiliation: Instituto Alberto Luiz Coimbra de Pós-Graduação e Pesquisa de Engenharia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
authors.forename: Alexandre Malta
authors.initials: AM
authors.lastname: Rossi
authors.affiliation: School of Dentistry, Universidade Federal Fluminense, Niteroi, RJ, Brazil.
authors.forename: José Mauro
authors.initials: JM
authors.lastname: Granjeiro
authors.affiliation: Department of Oral Surgery, School of Dentistry, Universidade Federal Fluminense, Niterói, RJ, Brazil.
authors.forename: Mônica Diuana
authors.initials: MD
authors.lastname: Calasans-Maia
mesh_terms: D000818:Animals; D001861:Bone Regeneration / Q000187:drug effects*; D018786:Bone Substitutes / Q000494:pharmacology*; D005260:Female; D006882:Hydroxyapatites / Q000494:pharmacology*; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D023421:Models, Animal; D049329:Nanostructures / Q000737:chemistry*; D015203:Reproducibility of Results; D012756:Sheep; D017550:Spectroscopy, Fourier Transform Infrared; D013324:Strontium / Q000494:pharmacology*; D013977:Tibia / Q000187:drug effects; D013997:Time Factors; D014945:Wound Healing / Q000187:drug effects*; D014961:X-Ray Diffraction; D055114:X-Ray Microtomography
chemical_list: D018786:Bone Substitutes; D006882:Hydroxyapatites; D013324:Strontium