title: The role of prosthetic abutment material on the stress distribution in a maxillary single implant-supported fixed prosthesis.
abstract: OBJECTIVE
  Evaluate the influence of abutment's material and geometry on stress distribution in a single implant-supported prosthesis.
  
  
  METHODS
  Three-dimensional models were made based on tomographic slices of the upper middle incisor area, in which a morse taper implant was positioned and a titanium (Ti) or zirconia (ZrN) universal abutments was installed. The commercially available geometry of titanium (T) and zirconia (Z) abutments were used to draw two models, TM1 and ZM1 respectively, which served as control groups. These models were compared with 2 experimental groups were the mechanical properties of Z were applied to the titanium abutment (TM2) and vice versa for the zirconia abutment (ZM2). Subsequently, loading was simulated in two steps, starting with a preload phase, calculated with the respective friction coefficients of each materials, followed by a combined preload and chewing force. The maximum von Mises stress was described. Data were analyzed by two-way ANOVA that considered material composition, geometry and loading (p<0.05).
  
  
  RESULTS
  Titanium and zirconia abutments showed similar von Mises stresses in the mechanical part of the four models. The area with the highest concentration of stress was the screw thread, following by the screw body. The highest stress levels occurred in screw thread was observed during the preloading phase in the ZM1 model (931MPa); and during the combined loading in the TM1 model (965MPa). Statistically significant differences were observed for loading, the material×loading interaction, and the loading×geometry interaction (p<0.05). Preloading contributed for 77.89% of the stress (p<0.05). There were no statistically significant differences to the other factors (p>0.05).
  
  
  CONCLUSIONS
  The screw was the piece most intensely affected, mainly through the preload force, independent of the abutment's material.
authors.affiliation: Implantology Team, Latin American Institute of Research and Education in Dentistry, Curitiba, Paraná, Brazil. Electronic address: hugo.e.peixoto@hotmail.com.
authors.forename: Hugo Eduardo
authors.initials: HE
authors.lastname: Peixoto
authors.affiliation: Department of Prosthodontics and Periodontology, Piracicaba Dental School, State University of Campinas, Limeira avenue, 901-Vila Rezende, Piracicaba, SP 13414-903, Brazil. Electronic address: dimorvan_bordin@hotmail.com.
authors.forename: Dimorvan
authors.initials: D
authors.lastname: Bordin
authors.affiliation: Department of Prosthodontics and Periodontology, Piracicaba Dental School, State University of Campinas, Limeira avenue, 901-Vila Rezende, Piracicaba, SP 13414-903, Brazil. Electronic address: altcury@fop.unicamp.br.
authors.forename: Altair A
authors.initials: AA
authors.lastname: Del Bel Cury
authors.affiliation: Department of Prosthodontics and Periodontology, Piracicaba Dental School, State University of Campinas, Limeira avenue, 901-Vila Rezende, Piracicaba, SP 13414-903, Brazil. Electronic address: wanderjose@fop.unicamp.br.
authors.forename: Wander José
authors.initials: WJ
authors.lastname: da Silva
authors.affiliation: Department of Restorative Dentistry, School of Dentistry, Federal University of Pelotas, Gonçalves Chaves, 457, 2nd floor, Pelotas, Rio Grande do Sul 96015-560, Brazil. Electronic address: fernanda.faot@gmail.com.
authors.forename: Fernanda
authors.initials: F
authors.lastname: Faot
mesh_terms: D015921:Dental Implants; D003764:Dental Materials / Q000737:chemistry*; D019094:Dental Prosthesis, Implant-Supported / Q000379:methods*; D003799:Dental Stress Analysis; D006801:Humans; D013314:Stress, Mechanical; D014025:Titanium / Q000737:chemistry; D015040:Zirconium / Q000737:chemistry
chemical_list: D015921:Dental Implants; D003764:Dental Materials; D015040:Zirconium; D014025:Titanium; C028541:zirconium oxide
keywords: Dental implant-abutment design; Dental implants; Finite element analysis; Titanium; Zirconia