title: A Comparative Analysis on Two Types of Oral Implants, Bone-Level and Tissue-Level, with Different Cantilever Lengths of Fixed Prosthesis.
abstract: OBJECTIVE
  Depending on esthetic, anatomical, and functional aspects, in implant-prosthetic restoration of a completely edentulous jaw, the selection of implant type is highly important; however, bone- and tissue-level implants and their stress distribution in bone have not yet been comparatively investigated. Hence, finite element analysis was used to study the influence of cantilever length in a fixed prosthesis on stress distribution in peri-implant bone around these two types of oral implants.
  
  
  METHODS
  A 3D edentulous mandible was modeled. In simulations, a framework with four posterior cantilever lengths and two types of implants, bone-level and tissue-level, was considered. A compressive load was applied to the distal regions of the cantilevers, and the von-Mises stress of peri-implant bone was investigated. The independent t-test and the Pearson correlation coefficient analyzed the results (α = 0.05).
  
  
  RESULTS
  Stresses in the cortical bone around the bone-level implants were greater than those in the tissue-level implants with the same cantilever length. In addition, by extending the cantilever length, the stress values in peri-implant bone increased. Therefore, when the cantilever was at its maximum length, the maximum stress was in cortical bone and around the bone-level distal implants.
  
  
  CONCLUSIONS
  The results of the present study indicate that treatment with tissue-level implants is potentially more advantageous than with bone-level implants for implant-supported fixed prostheses.
authors.affiliation: Department of Mechanical Engineering, Isfahan University of Technology, Isfahan, Iran.
authors.forename: Alireza
authors.initials: A
authors.lastname: Mosavar
authors.affiliation: Department of Prosthodontics, Faculty of Dentistry, Islamic Azad University Isfahan (Khorasgan) Branch, Isfahan, Iran.
authors.forename: Monireh
authors.initials: M
authors.lastname: Nili
authors.affiliation: Department of Prosthodontics, Faculty of Dentistry, Islamic Azad University Isfahan (Khorasgan) Branch, Isfahan, Iran.
authors.forename: Sayed Raouf
authors.initials: SR
authors.lastname: Hashemi
authors.affiliation: Department of Mechanical Engineering, Isfahan University of Technology, Isfahan, Iran.
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Kadkhodaei
mesh_terms: D003198:Computer Simulation; D015921:Dental Implants; D017267:Dental Prosthesis Design; D019094:Dental Prosthesis, Implant-Supported; D003799:Dental Stress Analysis; D004955:Esthetics, Dental; D020342:Finite Element Analysis; D006801:Humans; D007575:Jaw, Edentulous; D008334:Mandible
chemical_list: D015921:Dental Implants
keywords: Bone-level implant; cantilever length; finite element method; implant-supported fixed prosthesis; tissue-level implant