title: Biomechanical response of implant systems placed in the maxillary posterior region under various conditions of angulation, bone density, and loading.
abstract: OBJECTIVE
  The aim of this study was to determine the relative contribution of changes in implant system, position, bone type, and loading condition on the biomechanical response of a single-unit implant-supported restoration using nonlinear 3-dimensional finite element analysis (3D FEA).
  
  
  METHODS
  FEA models of a single-unit (crown) restoration supported by the Frialit-2 implant and MH-6 abutment or the Straumann standard implant with the Straumann solid abutment were used. Each system was analyzed by FEA with both straight and 20-degree angled abutments. Simulated implant placement was performed in the maxillary premolar area with 3 variations in implant orientation relative to the residual ridge. Analysis of each orientation was conducted for each of 4 bone quality types described by Lekholm and Zarb, with lateral and axial loading conditions imposed. The effect of each variable was expressed as a percentage of the total sum of squares as computed using analysis of variance.
  
  
  RESULTS
  Larger strain values were noted in cortical bone with lateral force and the Frialit-2 system. Bone strain increased with decreasing bone density and was affected primarily by bone quality. Implant stress was influenced mainly by implant position.
  
  
  CONCLUSIONS
  Better stress/strain distribution is possible when implants are placed along the axis of loading with multiple areas of cortical contact. The Straumann solid abutment performed better as a force-transmission mechanism.
authors.affiliation: Department of Mechanical Engineering, Chang Gung University, Tao-yuan, Taiwan.
authors.forename: Chun-Li
authors.initials: CL
authors.lastname: Lin
authors.forename: Jen-Chyan
authors.initials: JC
authors.lastname: Wang
authors.forename: Lance C
authors.initials: LC
authors.lastname: Ramp
authors.forename: Perng-Ru
authors.initials: PR
authors.lastname: Liu
mesh_terms: D000539:Alveolar Process / Q000601:surgery; D001641:Bicuspid; D001696:Biomechanical Phenomena; D015519:Bone Density; D003198:Computer Simulation; D003442:Crowns; D000044:Dental Abutments; D003758:Dental Implantation, Endosseous / Q000379:methods*; D019250:Dental Implants, Single-Tooth; D017267:Dental Prosthesis Design; D003799:Dental Stress Analysis / Q000379:methods*; D020342:Finite Element Analysis; D006801:Humans; D021621:Imaging, Three-Dimensional; D008437:Maxilla; D017711:Nonlinear Dynamics; D013314:Stress, Mechanical; D014057:Tomography, X-Ray Computed; D016474:Weight-Bearing