title: Physico-chemical characterization of zirconia-titania composites coated with an apatite layer for dental implants.
abstract: OBJECTIVE
  To investigate the crystalline phases, morphological features and functional groups on the surface of sintered Y:TZP/TiO2 composite ceramics before and after the application of a biomimetic bone-like apatite layer. The effect of TiO2 content on the composite's characteristics was also evaluated.
  
  
  METHODS
  Samples of Y:TZP containing 0-30mol% TiO2 were synthesized by co-precipitation, followed by filtration, drying and calcination. The powders were uniaxially pressed and sintered at 1500°C/1h. To obtain biomimetic coatings the samples were exposed to sodium silicate solution and then to a concentrated simulated body fluid solution. The surfaces, before and after coating, were characterized by diffuse reflectance infrared Fourier transformed spectroscopy, X-ray diffraction analysis and scanning electron microscopy.
  
  
  RESULTS
  The surfaces of all Y:TZP/TiO2 samples were covered with a dense and uniform calcium phosphate layer with a globular microstructure. This layer was crystalline for specimens with 30% of TiO2 and amorphous for specimens with 0 and 10% of TiO2. Chemical analysis indicated that this layer was composed of type A carbonate apatite. Among the materials tested, the composite with 10% of TiO2 showed the best overall chemical and physical features, such as higher density and more cohesive amorphous apatite layer.
  
  
  CONCLUSIONS
  Y-TZP-based materials obtained in the present investigation by means of the successful association of a calcium phosphate biomimetic layer with small amounts TiO2 should be further explored as an option for ceramic dental implants with improved bioactivity.
authors.affiliation: Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Santo André, SP, Brazil. juliana.marchi@ufabc.edu.br
authors.forename: Juliana
authors.initials: J
authors.lastname: Marchi
authors.forename: Eric M
authors.initials: EM
authors.lastname: Amorim
authors.forename: Dolores R R
authors.initials: DR
authors.lastname: Lazar
authors.forename: Valter
authors.initials: V
authors.lastname: Ussui
authors.forename: Ana Helena A
authors.initials: AH
authors.lastname: Bressiani
authors.forename: Paulo Francisco
authors.initials: PF
authors.lastname: Cesar
mesh_terms: D001031:Apatites / Q000737:chemistry*; D040761:Biomimetic Materials / Q000737:chemistry; D002130:Calcium Phosphates / Q000737:chemistry; D055598:Chemical Phenomena; D011232:Chemical Precipitation; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D003460:Crystallization; D003461:Crystallography; D015921:Dental Implants; D003764:Dental Materials / Q000737:chemistry*; D017267:Dental Prosthesis Design; D003890:Desiccation; D005374:Filtration; D006358:Hot Temperature; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D011312:Pressure; D017640:Silicates / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*; D014961:X-Ray Diffraction; D015019:Yttrium / Q000737:chemistry*; D015040:Zirconium / Q000737:chemistry*
chemical_list: D001031:Apatites; D002130:Calcium Phosphates; D020099:Coated Materials, Biocompatible; D015921:Dental Implants; D003764:Dental Materials; D017640:Silicates; C499362:yttria stabilized tetragonal zirconia; C009495:titanium dioxide; C030782:carboapatite; D015019:Yttrium; C020243:calcium phosphate; D015040:Zirconium; D014025:Titanium; C005691:sodium silicate
keywords: Biomimetic coating; Ceramic composite; Dental implant; Titania; Y-TZP