title: Comparing the influence of crestal cortical bone and sinus floor cortical bone in posterior maxilla bi-cortical dental implantation: a three-dimensional finite element analysis.
abstract: OBJECTIVE
  This study aimed to compare the influence of alveolar ridge cortical bone and sinus floor cortical bone in sinus areabi-cortical dental implantation by means of 3D finite element analysis.
  
  
  METHODS
  Three-dimensional finite element (FE) models in a posterior maxillary region with sinus membrane and the same height of alveolar ridge of 10 mm were generated according to the anatomical data of the sinus area. They were either with fixed thickness of crestal cortical bone and variable thickness of sinus floor cortical bone or vice versa. Ten models were assumed to be under immediate loading or conventional loading. The standard implant model based on the Nobel Biocare implant system was created via computer-aided design software. All materials were assumed to be isotropic and linearly elastic. An inclined force of 129 N was applied.
  
  
  RESULTS
  Von Mises stress mainly concentrated on the surface of crestal cortical bone around the implant neck. For all the models, both the axial and buccolingual resonance frequencies of conventional loading were higher than those of immediate loading; however, the difference is less than 5%.
  
  
  CONCLUSIONS
  The results showed that bi-cortical implant in sinus area increased the stability of the implant, especially for immediately loading implantation. The thickness of both crestal cortical bone and sinus floor cortical bone influenced implant micromotion and stress distribution; however, crestal cortical bone may be more important than sinus floor cortical bone.
authors.affiliation: Department of Prosthodontics.
authors.forename: Xu
authors.initials: X
authors.lastname: Yan
authors.forename: Xinwen
authors.initials: X
authors.lastname: Zhang
authors.forename: Weichao
authors.initials: W
authors.lastname: Chi
authors.forename: Hongjun
authors.initials: H
authors.lastname: Ai
authors.forename: Lin
authors.initials: L
authors.lastname: Wu
mesh_terms: D000539:Alveolar Process / Q000033:anatomy & histology* / Q000502:physiology; D001696:Biomechanical Phenomena; D003198:Computer Simulation; D017076:Computer-Aided Design; D003758:Dental Implantation, Endosseous / Q000379:methods; D015921:Dental Implants; D017267:Dental Prosthesis Design; D017268:Dental Prosthesis Retention; D020342:Finite Element Analysis; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D057893:Immediate Dental Implant Loading; D008437:Maxilla / Q000033:anatomy & histology* / Q000502:physiology / Q000601:surgery; D008443:Maxillary Sinus / Q000033:anatomy & histology* / Q000502:physiology; D008953:Models, Anatomic; D008954:Models, Biological; D009297:Nasal Mucosa / Q000033:anatomy & histology; D013314:Stress, Mechanical; D013499:Surface Properties; D014732:Vibration
chemical_list: D015921:Dental Implants
keywords: bi-cortical implant; finite element analysis; resonance frequencies; sinus floor; stress distribution