title: Functionalized pink Al2O3:Mn pigments applied in prosthetic dentistry.
abstract: BACKGROUND
  The color of dental poly(methyl methacrylate) (PMMA) is conventionally rendered by organic and inorganic pigments, which are usually not bonded to the polymer network. Functionalized ceramic pigments can be used to color PMMA, allowing improved chemical interaction with the resin matrix.
  
  
  OBJECTIVE
  The purpose of this in vitro study was to synthesize, functionalize, and characterize pink manganese-doped alumina ceramic pigments. The hypothesis tested was that functionalized ceramic pigments would render pink coloration to a translucent PMMA without jeopardizing its mechanical properties.
  
  
  METHODS
  Pink alumina powders doped with 1 or 2 mol% of manganese (Al2O3:Mn) were prepared by means of a polymeric precursor method. Pigment (Pig.) particles were functionalized with a silica coating method followed by silanation before preparation of PMMA-based composite resins (5 wt% pigment). The color of composite resins (Pig.1% and Pig.2%) and PMMA controls (Pink and translucent [Trans]) was evaluated (CIELab color coordinates), and their mechanical properties were tested (3-point bending).
  
  
  RESULTS
  The microstructure of the pigment particles showed approximately 55-nm nanocrystals of manganese-doped α-alumina clustered into irregular porous particles up to 60 μm. The composite resins and pink PMMA showed similar color parameters (CIE a* pink=20.1, Pig.1%=14.6, Pig.2%=16.0, Trans=0.19, P<.001; CIE b* Pink=17.0, Pig.1%=18.6, Pig.2%=19.0, Trans=2.52, P<.001). No statistical differences were observed in mechanical properties among groups (σfpink=98.4, Pig.1%=98.1, Pig.2%=98.8, trans=89.1, P=.136).
  
  
  CONCLUSIONS
  The addition of the functionalized pink ceramic pigments to a translucent PMMA yielded similar coloration to that of the regular pink PMMA used in dentistry and did not jeopardize its mechanical properties.
authors.affiliation: Professor, School of Dentistry, Federal University of Pelotas, Brazil.
authors.forename: Mário Thadeo R
authors.initials: MTR
authors.lastname: Cruzeiro
authors.affiliation: Undergraduate student, School of Materials Science and Engineering, Federal University of Pelotas, Pelotas, Brazil.
authors.forename: Fernando A
authors.initials: FA
authors.lastname: Moraes
authors.affiliation: Post-doctoral fellow, Graduate Program in Materials Science and Engineering, Federal University of Pelotas, Pelotas, Brazil. Electronic address: marinakaizer@gmail.com.
authors.forename: Marina R
authors.initials: MR
authors.lastname: Kaizer
authors.affiliation: Professor, Graduate Program in Physics and Mathematics, Federal University of Pelotas, Pelotas, Brazil.
authors.forename: Mário Lúcio
authors.initials: ML
authors.lastname: Moreira
authors.affiliation: Professor, Department of Biomaterials and Biomimetics, New York University College of Dentistry, New York, NY.
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Professor, Graduate Program in Dentistry, Federal University of Pelotas, Brazil.
authors.forename: Rafael R
authors.initials: RR
authors.lastname: Moraes
authors.affiliation: Professor, Graduate Program in Materials Science and Engineering, Federal University of Pelotas, Pelotas, Brazil.
authors.forename: Sergio S
authors.initials: SS
authors.lastname: Cava
mesh_terms: D000537:Aluminum Oxide; D002516:Ceramics; D003764:Dental Materials; D017267:Dental Prosthesis Design / Q000379:methods*; D008345:Manganese; D008422:Materials Testing; D019904:Polymethyl Methacrylate; D017797:Prosthesis Coloring
chemical_list: D003764:Dental Materials; D008345:Manganese; D019904:Polymethyl Methacrylate; D000537:Aluminum Oxide