title: Finite Element Analysis of Bone Stress around Micro-Implants of Different Diameters and Lengths with Application of a Single or Composite Torque Force.
abstract: BACKGROUND
  Stress on the bone surrounding dental micro-implants affects implant success.
  
  
  OBJECTIVE
  To compare the stress on the bone surrounding a micro-implant after application of a single force (SF) of 200 g or a composite force (CF) of 200 g and 6 N.mm torque.
  
  
  METHODS
  Finite element models were developed for micro-implant diameters of 1.2, 1.6, and 2.0 mm, and lengths of 6, 8, 10, and 12 mm and either a SF or CF was applied. The maximum equivalent stress (Max EQS) of the bone surrounding the micro-implant was determined, and the relationships among type of force, diameter, and length were evaluated.
  
  
  RESULTS
  The Max EQS of the CF exceeded that of the SF (P< 0.05). The effect of force on stress was related to implant diameter, but not to implant length. The larger CF led to greater instability of the micro-implant and the effect was most pronounced at an implant diameter of 1.2 mm. The use of implant diameters of 1.6 mm and 2.0 mm produced no significant difference in implant stability when either a CF or SF was applied.
  
  
  CONCLUSIONS
  When considering the use of an implant to perform three-dimensional control on the teeth, the implant diameter chosen should be > 1.2 mm.
authors.affiliation: Department of Stomatology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, Guangdong Province, China.
authors.forename: Ying-juan
authors.initials: YJ
authors.lastname: Lu
authors.affiliation: Department of Stomatology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, Guangdong Province, China.
authors.forename: Shao-hai
authors.initials: SH
authors.lastname: Chang
authors.affiliation: Department of Stomatology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, Guangdong Province, China.
authors.forename: Jian-tao
authors.initials: JT
authors.lastname: Ye
authors.affiliation: Department of Stomatology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, Guangdong Province, China.
authors.forename: Yu-shan
authors.initials: YS
authors.lastname: Ye
authors.affiliation: Department of Stomatology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, Guangdong Province, China.
authors.forename: Yan-song
authors.initials: YS
authors.lastname: Yu
mesh_terms: D001696:Biomechanical Phenomena; D019245:Compressive Strength; D015921:Dental Implants; D017267:Dental Prosthesis Design; D003799:Dental Stress Analysis; D020342:Finite Element Analysis; D006801:Humans; D008334:Mandible / Q000033:anatomy & histology / Q000601:surgery; D008437:Maxilla / Q000033:anatomy & histology / Q000601:surgery; D008953:Models, Anatomic; D013314:Stress, Mechanical; D019415:Torque
chemical_list: D015921:Dental Implants