title: Evaluation of the effect of an offset implant configuration in the posterior maxilla with external hexagon implant platform: A 3-dimensional finite element analysis.
abstract: BACKGROUND
  Slight offset of the central implant in 3-unit implant-supported prostheses has been reported to improve biomechanical behavior. However, studies that assessed the effects of an offset implant configuration in the posterior maxilla are scarce.
  
  
  OBJECTIVE
  The purpose of this 3-dimensional (3D) finite element analysis was to assess the effects of splinting in 3-unit implant-supported prostheses with varying implant positions (straight-line or offset configuration) in terms of the stress/strain distribution on bone tissue and the stress distribution on abutment screws.
  
  
  METHODS
  Three 3D models were used to simulate a posterior maxilla bone block (type IV): straight-line implants supporting single crowns (model M1), straight-line implants supporting 3-unit splinted fixed dental prosthesis (model M2), and an offset implant configuration supporting 3-unit splinted fixed dental prosthesis (model M3). The applied forces were 400 N axially and 200 N obliquely. The type of implant platform simulated was an external hexagon. von Mises stress on the abutment screws was measured, and the maximum principal stress and microstrain values were used to perform cortical bone tissue analysis. Analysis of variance (ANOVA) and the Tukey honest significant differences post hoc test were used to determine the significance of the results and interactions among the main variables (α=.05).
  
  
  RESULTS
  In all models, oblique load increased the stress on abutment screws and bone tissue and the microstrain on bone tissue. Model M3 decreased the stress concentration on the abutment screws and bone tissue. With regard to microstrain distribution, model M3 had the smallest values, and M1 and M2 had similar values.
  
  
  CONCLUSIONS
  Splinting associated with an offset implant configuration was effective for decreasing the stress on abutment screws and bone tissue and the microstrain on bone tissue.
authors.affiliation: Graduate student, Graduate Program in Dentistry, Department of Dental Materials and Prosthodontics, Araçatuba Dental School, São Paulo State University, São Paulo, Brazil. Electronic address: victor_edsb@hotmail.com.
authors.forename: Victor Eduardo
authors.initials: VE
authors.lastname: de Souza Batista
authors.affiliation: Assistant Professor, Department of Dental Materials and Prosthodontics, Araçatuba Dental School, São Paulo State University, São Paulo, Brazil.
authors.forename: Fellippo Ramos
authors.initials: FR
authors.lastname: Verri
authors.affiliation: Adjunct Professor, School of Dentistry, Federal University of Alfenas, Minas Gerais, Brazil.
authors.forename: Daniel Augusto de Faria
authors.initials: DAF
authors.lastname: Almeida
authors.affiliation: Assistant Professor, Department of Health Sciences, University of Sacred Heart, São Paulo, Brazil.
authors.forename: Joel Ferreira
authors.initials: JF
authors.lastname: Santiago Junior
authors.affiliation: Graduate student, Graduate Program in Dentistry, Department of Dental Materials and Prosthodontics, Araçatuba Dental School, São Paulo State University, São Paulo, Brazil.
authors.forename: Cleidiel Aparecido Araújo
authors.initials: CAA
authors.lastname: Lemos
authors.affiliation: Full Professor, Department of Dental Materials and Prosthodontics, Araçatuba Dental School, São Paulo State University, São Paulo, Brazil.
authors.forename: Eduardo Piza
authors.initials: EP
authors.lastname: Pellizzer
mesh_terms: D001696:Biomechanical Phenomena; D003442:Crowns; D000044:Dental Abutments; D019094:Dental Prosthesis, Implant-Supported / Q000379:methods*; D003799:Dental Stress Analysis; D020342:Finite Element Analysis; D006801:Humans; D021621:Imaging, Three-Dimensional; D008437:Maxilla; D013314:Stress, Mechanical