title: Stress analysis in simulation models with or without implant threads representation.
abstract: OBJECTIVE
  This study aimed to evaluate the influence of implants with or without threads representation on the outcome of a two-dimensional finite element (FE) analysis.
  
  
  METHODS
  Two-dimensional FE models that reproduced a frontal section of edentulous mandibular posterior bone were constructed using a standard crown/implant/screw system representation. To evaluate the effect of implant threads, two models were created: a model in which the implant threads were accurately simulated (precise model) and a model in which implants with a smooth surface (press-fit implant) were used (simplified model). An evaluation was performed on ANSYS software, in which a load of 133 N was applied at a 30-degree angulation and 2 mm off-axis from the long axis of the implant on the models. The Von Mises stresses were measured.
  
  
  RESULTS
  The precise model (1.45 MPa) showed higher maximum stress values than the simplified model (1.2 MPa). Whereas in the cortical bone, the stress values differed by about 36% (292.95 MPa for the precise model and 401.14 MPa for the simplified model), in trabecular bone (19.35 MPa and 20.35 MPa, respectively), the stress distribution and stress values were similar. Stress concentrations occurred around the implant neck and the implant apex.
  
  
  CONCLUSIONS
  Considering implant and cortical bone analysis, remarkable differences in stress values were found between the models. Although the models showed different absolute stress values, the stress distribution was similar.
authors.affiliation: Department of Dental materials and Prosthodontics, Araçatuba Dental School, São Paulo State University, São Paulo, Brazil. wirley@foa.unesp.br
authors.forename: Wirley Gonçalves
authors.initials: WG
authors.lastname: Assunção
authors.forename: Erica Alves
authors.initials: EA
authors.lastname: Gomes
authors.forename: Valentim Adelino Ricardo
authors.initials: VA
authors.lastname: Barão
authors.forename: Edson Antonio Capello
authors.initials: EA
authors.lastname: de Sousa
mesh_terms: D001696:Biomechanical Phenomena; D003198:Computer Simulation; D015921:Dental Implants; D017267:Dental Prosthesis Design; D003799:Dental Stress Analysis / Q000379:methods*; D055119:Elastic Modulus; D020342:Finite Element Analysis; D006801:Humans; D003765:Models, Dental; D008962:Models, Theoretical; D016348:Osseointegration; D013499:Surface Properties; D016474:Weight-Bearing
chemical_list: D015921:Dental Implants