title: Influence of parafunctional loading and prosthetic connection on stress distribution: a 3D finite element analysis.
abstract: BACKGROUND
  Clinicians should consider parafunctional occlusal load when planning treatment. Prosthetic connections can reduce the stress distribution on an implant-supported prosthesis.
  
  
  OBJECTIVE
  The purpose of this 3-dimensional finite element study was to assess the influence of parafunctional loading and prosthetic connections on stress distribution.
  
  
  METHODS
  Computer-aided design software was used to construct 3 models. Each model was composed of a bone and an implant (external hexagon, internal hexagon, or Morse taper) with a crown. Finite element analysis software was used to generate the finite element mesh and establish the loading and boundary conditions. A normal force (200-N axial load and 100-N oblique load) and parafunctional force (1000-N axial and 500-N oblique load) were applied. Results were visualized as the maximum principal stress. Three-way analysis of variance and Tukey test were performed, and the percentage of contribution of each variable to the stress concentration was calculated from sum-of squares-analysis.
  
  
  RESULTS
  Stress was concentrated around the implant at the cortical bone, and models with the external hexagonal implant showed the highest stresses (P<.001). Oblique loads produced high tensile stress concentrations on the site opposite the load direction.
  
  
  CONCLUSIONS
  Internal connection implants presented the most favorable biomechanical situation, whereas the least favorable situation was the biomechanical behavior of external connection implants. Parafunctional loading increased the magnitude of stress by 3 to 4 times.
authors.affiliation: Postgraduate student, Department of Dental Materials and Prosthodontics, State University of Paulista, Araçatuba Dental School, São Paulo, Brazil.
authors.forename: Leonardo Bueno
authors.initials: LB
authors.lastname: Torcato
authors.affiliation: Adjunct Professor, Department of Dental Materials and Prosthodontics, State University of Paulista, Araçatuba Dental School, São Paulo, Brazil.
authors.forename: Eduardo Piza
authors.initials: EP
authors.lastname: Pellizzer
authors.affiliation: Associate Professor, Department of Dental Materials and Prosthodontics, State University of Paulista, Araçatuba Dental School, São Paulo, Brazil.
authors.forename: Fellippo Ramos
authors.initials: FR
authors.lastname: Verri
authors.affiliation: Postdoctoral researcher, Department of Dental Materials and Prosthodontics, State University of Paulista, Araçatuba Dental School, São Paulo, Brazil. Electronic address: rosse_falcon@yahoo.com.br.
authors.forename: Rosse Mary
authors.initials: RM
authors.lastname: Falcón-Antenucci
authors.affiliation: Postgraduate student, Department of Dental Materials and Prosthodontics, State University of Paulista, Araçatuba Dental School, São Paulo, Brazil.
authors.forename: Joel Ferreira
authors.initials: JF
authors.lastname: Santiago Júnior
authors.affiliation: Postgraduate student, Department of Dental Materials and Prosthodontics, State University of Paulista, Araçatuba Dental School, São Paulo, Brazil.
authors.forename: Daniel Augusto
authors.initials: DA
authors.lastname: de Faria Almeida
mesh_terms: D017267:Dental Prosthesis Design; D019094:Dental Prosthesis, Implant-Supported; D003799:Dental Stress Analysis; D020342:Finite Element Analysis; D006801:Humans; D012984:Software; D013314:Stress, Mechanical