title: Biomechanical effect of platform switching in implant dentistry: a three-dimensional finite element analysis.
abstract: OBJECTIVE
  The purpose of this study was to analyze and compare the implant-bone interface stresses in anisotropic three-dimensional finite element models of an osseointegrated implant with platform switching and a conventional matching-diameter implant platform and abutment in the posterior maxilla.
  
  
  METHODS
  Three-dimensional finite element models were created of a first molar section of the maxilla and embedded with a single endosseous implant (4.1 3 10 mm). One model simulated a 4.1-mm-diameter abutment connection and the other was a narrower 3.4-mm-diameter abutment connection, ie, simulating a platform-switching configuration. A gold alloy crown with 2-mm occlusal thickness was applied over the titanium abutment. Material properties of compact and cancellous bone were modeled as fully orthotropic and transversely isotropic, respectively. Oblique (200-N vertical and 40-N horizontal) occlusal loads were applied and perfect bonding was assumed at all interfaces.
  
  
  RESULTS
  Maximum von Mises, compressive, and tensile stresses in compact bone were lower in the platform-switching model than in the conventional model. However, the maximum von Mises stress in cancellous bone was higher in the platform-switching model than in the conventional model.
  
  
  CONCLUSIONS
  The platform-switching technique reduced the stress concentration in the area of compact bone and shifted it to the area of cancellous bone during oblique loading.
authors.affiliation: Department of Dentistry, National Yang-Ming University, Tapei, Taiwan. mlhsu@ym.edu.tw
authors.forename: Chih-Ling
authors.initials: CL
authors.lastname: Chang
authors.forename: Chen-Sheng
authors.initials: CS
authors.lastname: Chen
authors.forename: Ming-Lun
authors.initials: ML
authors.lastname: Hsu
mesh_terms: D016880:Anisotropy; D001696:Biomechanical Phenomena; D001732:Bite Force; D003442:Crowns; D000044:Dental Abutments; D019250:Dental Implants, Single-Tooth; D003764:Dental Materials / Q000737:chemistry; D017267:Dental Prosthesis Design; D019094:Dental Prosthesis, Implant-Supported; D055119:Elastic Modulus; D020342:Finite Element Analysis; D006047:Gold Alloys / Q000737:chemistry; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008437:Maxilla / Q000473:pathology; D008963:Molar; D016348:Osseointegration / Q000502:physiology; D013314:Stress, Mechanical; D014025:Titanium / Q000737:chemistry
chemical_list: D003764:Dental Materials; D006047:Gold Alloys; D014025:Titanium