title: [Effect of the thickness of periodontal ligament on the fracture resistance of root and post-core system].
abstract: OBJECTIVE
  To assess the effect of the thickness of periodontal ligament on the fracture resistance of root and post-core system.
  
  
  METHODS
  Forty-five simulated roots in the same length, taper and diameter were made of polymethacrylate (PMMA). Then the wax patterns of post-cores were cast. Soft lining material was used to simulated periodontal ligament. And each specimen was embedded in acrylic resin and then fixed in a special jig on the universal load-testing machine. A compressive load was applied at a 90-degree angle to the long axis of the core until fracture, at a crosshead speed of 1 mm/min. The maximum of load and the displacement were recorded.
  
  
  RESULTS
  The mean values of load in root and post-core system were 148.033 N, 161.889 N, 168.667 N, 181.589 N, 194.622 N, and the mean values of displacement were 1.965 mm, 2.837 mm, 3.327 mm, 3.927 mm, 5.326 mm.
  
  
  CONCLUSIONS
  The fracture resistance and displacement of root and post-core system with the same quality and altitude periodontal ligament are associated with the thickness of periodontal ligament when the range of thickness is from 0.2 mm to 1.0 mm.
authors: Key Laboratory of Oral Biomedical Engineering of Ministry of Education, Sichuan University, Chengdu 610041, China.
authors: Shan-chuan
authors: SC
authors: Zhang
authors: Xin-min
authors: XM
authors: Chen
authors: Pin
authors: P
authors: Zhou
authors: Lu
authors: L
authors: Pan
authors: Shu
authors: S
authors: Wang
mesh_terms: D000180:Acrylic Resins; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D006801:Humans; D010513:Periodontal Ligament; D011176:Post and Core Technique; D014082:Tooth Fractures; D014092:Tooth Root
chemical_list: D000180:Acrylic Resins