title: The effect of platform switching on stress in peri-implant bone in a condition of marginal bone resorption: a three-dimensional finite element analysis.
abstract: OBJECTIVE
  The aim of the present study was to investigate the stress distribution in the bone around a platform-switched implant with marginal bone loss.
  
  
  METHODS
  Finite element models of an implant-supported crown on a mandibular first molar were constructed and included an osseointegrated implant, a metal crown, and cancellous and cortical bone. Two kinds of abutments, conventional and platform-switched, were imported into the model. A variety of different levels of conical marginal bone resorption, from 0 to 2.0 mm in height and width, was created around the implant neck. The stresses generated in the peri-implant bone tissue were analyzed under 200 N of vertical or oblique loading.
  
  
  RESULTS
  The location of stress concentration extended from the implant neck toward the apex in association with increases in bone resorption depth. In the bone-resorbed models, the platform-switched implant showed lower maximum equivalent stresses in the peri-implant bone than the conventional abutment. The difference between the two implant models decreased as bone resorption increased.
  
  
  CONCLUSIONS
  Within the limitations of this study, the results suggest a biomechanical advantage for platform switching in a condition of marginal bone resorption, but this advantage may be weakened when bone resorption is dramatic. Additional animal or clinical studies are necessary to better clarify the effects of peri-implant bone defects on the biomechanical features of a platform-switched configuration.
authors.affiliation: The State Key Laboratory Breeding Base of Basic Science of Stomatology, Hubei-MOST and Ministry of Education and Department of Oral Implantology, School and Hospital of Stromatology, Wuhan University, Wuhan, China.
authors.forename: Haibin
authors.initials: H
authors.lastname: Xia
authors.forename: Min
authors.initials: M
authors.lastname: Wang
authors.forename: Li
authors.initials: L
authors.lastname: Ma
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhou
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Li
authors.forename: Yining
authors.initials: Y
authors.lastname: Wang
mesh_terms: D001862:Bone Resorption / Q000473:pathology / Q000503:physiopathology*; D003442:Crowns; D000044:Dental Abutments; D059605:Dental Implant-Abutment Design; D015921:Dental Implants; D003799:Dental Stress Analysis / Q000379:methods*; D020342:Finite Element Analysis; D008334:Mandible; D008963:Molar; D016348:Osseointegration
chemical_list: D015921:Dental Implants