title: Influence of different post-core systems on impact stress: a pilot study.
abstract: This pilot study compared impact strain at the core and root surfaces between two different post-core systems.
  
  
  METHODS
  The form of a bovine mandibular front tooth was modified to resemble that of a human maxillary incisor as a test specimen. A cast post and core (Metal PC) and composite resin and glass fiber-reinforced epoxy resin post (Fiber-Resin PC) system were tested. Four gauges were affixed to the buccal and lingual surfaces of the core and root. The specimens were then embedded in a metal mold using dental stone. A pendulum-type device with a pyramid-shaped metal impact object with a titanium alloy head was used to provide 2 different shock forces. Maximum distortion was measured and analyzed.
  
  
  RESULTS
  Distortion at the core at each measurement point and total amount of distortion with Fiber-Resin PC was significantly greater (p<0.05) than that with Metal PC against both impact forces. On the other hand, distortion at the root at the buccal measurement point with Fiber-Resin PC was significantly less than that with Metal PC against both impact forces. Total distortion was significantly less with Fiber-Resin PC than that with Metal PC against the greater impact shock. Acceleration with Fiber-Resin PC was significantly less than that with Metal PC against both impact forces.
  
  
  CONCLUSIONS
  Fiber-Resin PC has the potential to protect remaining root against traumatic force. This suggests that a Fiber-Resin PC is more suitable for non-vital teeth against not only occlusal but also traumatic impact force.
authors.affiliation: Department of General Dentistry, Tokyo Dental College Chiba Hospital.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Kondoh
authors.affiliation: Department of Sports Dentistry, Tokyo Dental College.
authors.forename: Tomotaka
authors.initials: T
authors.lastname: Takeda
authors.affiliation: Department of Sports Dentistry, Tokyo Dental College.
authors.forename: Takamitsu
authors.initials: T
authors.lastname: Ozawa
authors.affiliation: Department of Sports Dentistry, Tokyo Dental College.
authors.forename: Keishiro
authors.initials: K
authors.lastname: Narimatsu
authors.affiliation: Department of Sports Dentistry, Tokyo Dental College.
authors.forename: Michiyo
authors.initials: M
authors.lastname: Konno
authors.affiliation: Department of Sports Dentistry, Tokyo Dental College.
authors.forename: Toshiki
authors.initials: T
authors.lastname: Fujii
authors.affiliation: Department of Sports Dentistry, Tokyo Dental College.
authors.forename: Chieko
authors.initials: C
authors.lastname: Sekiguchi
authors.affiliation: Department of Sports Dentistry, Tokyo Dental College.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Nakajima
authors.affiliation: Department of Sports Dentistry, Tokyo Dental College.
authors.forename: Keiichi
authors.initials: K
authors.lastname: Ishigami
authors.affiliation: Department of Pediatric Dentistry, Matsumoto Dental University School of Dentistry ; Division of Oral Health Promotion, Matsumoto Dental University Graduate School.
authors.forename: Masahito
authors.initials: M
authors.lastname: Shomura
keywords: Acceleration; distortion; glass fiber-reinforced epoxy resin post; impact force; post-core system; root.