title: FEA and microstructure characterization of a one-piece Y-TZP abutment.
abstract: OBJECTIVE
  The most important drawback of dental implant/abutment assemblies is the need for a fixing screw. This study aimed to develop an esthetic one-piece Y-TZP abutment to suppress the use of the screw.
  
  
  METHODS
  Material characterization was performed using a bar-shaped specimen obtained by slip-casting to validate the method prior to prototype abutment fabrication by the same process. The mechanical behavior of the prototype abutment was verified and compared with a conventional abutment by finite element analysis (FEA). The abutment was evaluated by micro-CT analysis and its density was measured.
  
  
  RESULTS
  FEA showed stress concentration at the first thread pitch during installation and in the cervical region during oblique loading for both abutments. However, stress concentration was observed at the base of the screw head and stem in the conventional abutment. The relative density for the fabricated abutment was 95.68%. Micro-CT analysis revealed the presence of elongated cracks with sharp edges over the surface and porosity in the central region.
  
  
  CONCLUSIONS
  In the light of these findings, the behavior of a one-piece abutment is expected to be better than that of the conventional model. New studies should be conducted to clarify the performance and longevity of this one-piece Y-TZP abutment.
authors.affiliation: Department of Biomaterials and Oral Biology, Faculty of Dentistry, University of São Paulo (USP), São Paulo, São Paulo, Brazil. Electronic address: cdhian@gmail.com.
authors.forename: Lucas Hian
authors.initials: LH
authors.lastname: da Silva
authors.affiliation: Department of Materials Engineering, Lorena's Engineering School, University of São Paulo (USP), Lorena, São Paulo, Brazil.
authors.forename: Sebastião
authors.initials: S
authors.lastname: Ribeiro
authors.affiliation: Department of Dental Materials and Prosthodontics, Faculty of Dentistry, São Paulo State University (UNESP), São José dos Campos, São Paulo, Brazil.
authors.forename: Alexandre Luís Souto
authors.initials: AL
authors.lastname: Borges
authors.affiliation: Department of Biomaterials and Oral Biology, Faculty of Dentistry, University of São Paulo (USP), São Paulo, São Paulo, Brazil.
authors.forename: Paulo Francisco
authors.initials: PF
authors.lastname: Cesar
authors.affiliation: Department of Dental Materials and Prosthodontics, Faculty of Dentistry, São Paulo State University (UNESP), São José dos Campos, São Paulo, Brazil.
authors.forename: Rubens Nisie
authors.initials: RN
authors.lastname: Tango
mesh_terms: D000044:Dental Abutments; D020342:Finite Element Analysis; D006801:Humans
keywords: Biomaterials; Ceramics; Dental implant; Esthetic dentistry; Implant abutment; Oral rehabilitation; Prosthodontics; Slip-cast; Y-TZP