title: Angular immediate loading: three-dimensional finite element analysis.
abstract: OBJECTIVE
  The aim of the study was to analyze the stress distribution in the bone around implants under 0, 5, 10, and 20 degrees of loading.
  
  
  METHODS
  Four mandible models, embedded with cylindrical implants with immediate-load angle of 0, 5, 10, and 20 degrees, were analyzed using the software ANSYS 10.0. The von Mises stress of the implant-bone interface mainly including the implant neck as well as the middle and apex areas was calculated when the implants were loaded with 200-N forces.
  
  
  RESULTS
  Stress is mainly concentrated in the bone interface of the implant neck. With the loading implant inclining by 20 degrees, the stress concentrated in the neck of the distal side bone interface is of statistical significance (P < 0.05) when compared with the other groups; when inclined by 0 and 5 degrees, there is no statistical significance; when inclined by 10 degrees, there is statistical significance. The stress in the mesial side of the implant-bone interface is relatively small, and it has no statistical significance in each corresponding site (P > 0.05).
  
  
  CONCLUSIONS
  The immediate load of the implant mainly increases the stress in the cortical bone around the neck of the implant. It is necessary to pay attention to the impact of the stress at the angle greater than 20 degrees or above on the implant neck; the stress in change is not obvious in the middle and apex areas of the implant as well as in the middle and apex areas of the implant under a lateral force within 20 degrees.
authors.affiliation: From the *Stomatology School of Shandong University; †Department of Oral and Maxillofacial Surgery, The Second Hospital of Shandong University; and ‡Department of Stomatology, the Central Hospital of Jinan City, Jinan, People's Republic of China.
authors.forename: Luo
authors.initials: L
authors.lastname: Sheng-Lei
authors.forename: Xu
authors.initials: X
authors.lastname: Xin
authors.forename: Yuan
authors.initials: Y
authors.lastname: Kui-feng
authors.forename: Lai
authors.initials: L
authors.lastname: Qing-guo
authors.forename: Tang
authors.initials: T
authors.lastname: Xiao-peng
authors.forename: Li
authors.initials: L
authors.lastname: Ying
mesh_terms: D015921:Dental Implants; D003799:Dental Stress Analysis / Q000379:methods*; D020342:Finite Element Analysis; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D057893:Immediate Dental Implant Loading; D008334:Mandible; D008954:Models, Biological; D013314:Stress, Mechanical
chemical_list: D015921:Dental Implants