title: [Influence of helix angle and density on primary stability of immediately loaded dental implants: three-dimensional finite element analysis].
abstract: OBJECTIVE
  To analyze effects of different thread helix angles and densities on the primary stability of immediately loaded implants using the three-dimensional finite element model analysis.
  
  
  METHODS
  Five models of three-dimensional finite element (0.8 mm, 1.6 mm, 2.4 mm, double-threaded, and triple-threaded) were created using the commercial codes of Pro/E software, Hypermesh software, and ABAQUS software. In conditions of horizontal and vertical loading, the micro-motion of the finite element models with different thread helix angles and densities were computed with ABAQUS software.
  
  
  RESULTS
  Concerning different thread helix angles, the micro-motion of single-threaded implant was the minimum and that of the triple-threaded was the maximum with vertical and horizontal loading. The micro-motion of doubled-threaded implant was the minimum compared with thread pitch 1.6 mm and the micro-motion of triple-threaded implant was the minimum compared with thread pitch 2.4 mm with vertical and horizontal loading.
  
  
  CONCLUSIONS
  The thread helix angle and density of implants can greatly affect the vertical interfacial micro-motion. With increasing thread pitchs, the resistance of implant to vertical load is weakened; with increasing thread helix angle, the resistance of implant to vertical load is weakened; with increasing thread density, the resistance of implant to the vertical load is weakened.
authors.affiliation: Department of Oral Implantology, College of Stomatology, The Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Pan
authors.initials: P
authors.lastname: Ma
authors.forename: Hong-chen
authors.initials: HC
authors.lastname: Liu
authors.forename: De-hua
authors.initials: DH
authors.lastname: Li
authors.forename: Sheng
authors.initials: S
authors.lastname: Lin
authors.forename: Zhen
authors.initials: Z
authors.lastname: Shi
authors.forename: Qin-jian
authors.initials: QJ
authors.lastname: Peng
mesh_terms: D015921:Dental Implants; D017267:Dental Prosthesis Design; D003799:Dental Stress Analysis; D003781:Denture Retention; D020342:Finite Element Analysis
chemical_list: D015921:Dental Implants