title: Influences of implant neck design and implant-abutment joint type on peri-implant bone stress and abutment micromovement: three-dimensional finite element analysis.
abstract: OBJECTIVE
  Occlusal overloading is one of the causes of peri-implant bone resorption, and many studies on stress distribution in the peri-implant bone by three-dimensional finite element analysis (3D FEA) have been performed. However, the FEA models previously reported were simplified and far from representing what occurs in clinical situations. In this study, 3D FEA was conducted with simulation of the complex structure of dental implants, and the influences of neck design and connections with an abutment on peri-implant bone stress and abutment micromovement were investigated.
  
  
  METHODS
  Three types of two-piece implant CAD models were designed: external joint with a conical tapered neck (EJ), internal joint with a straight neck (IJ), and conical joint with a reverse conical neck (CJ). 3D FEA was performed with the setting of a "contact" condition at the component interface, and stress distribution in the peri-implant bone and abutment micromovement were analyzed.
  
  
  RESULTS
  The shear stress was concentrated on the mesiodistal side of the cortical bone for EJ. EJ had the largest amount of abutment micromovement. While the von Mises and shear stresses around the implant neck were concentrated on the labial bone for IJ, they were distributed on the mesiodistal side of the cortical bone for CJ. CJ had the least amount of abutment micromovement.
  
  
  CONCLUSIONS
  Implants with a conical joint with an abutment and reverse conical neck design may effectively control occlusal overloading on the labial bone and abutment micromovement.
authors.affiliation: Department of Biomaterials Science, Osaka University Graduate School of Dentistry, Osaka, Japan.
authors.forename: Yasufumi
authors.initials: Y
authors.lastname: Yamanishi
authors.forename: Satoshi
authors.initials: S
authors.lastname: Yamaguchi
authors.forename: Satoshi
authors.initials: S
authors.lastname: Imazato
authors.forename: Tamaki
authors.initials: T
authors.lastname: Nakano
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Yatani
mesh_terms: D000539:Alveolar Process / Q000502:physiology*; D001696:Biomechanical Phenomena; D001732:Bite Force; D016723:Bone Remodeling; D017076:Computer-Aided Design; D059605:Dental Implant-Abutment Design; D017268:Dental Prosthesis Retention; D003799:Dental Stress Analysis / Q000379:methods*; D020342:Finite Element Analysis; D006801:Humans; D021621:Imaging, Three-Dimensional; D009068:Movement; D016348:Osseointegration; D033081:Shear Strength; D013314:Stress, Mechanical