title: Effect of water temperature on cyclic fatigue properties of glass-fiber-reinforced hybrid composite resin and its fracture pattern after flexural testing.
abstract: OBJECTIVE
  To evaluate in vitro the influence of dynamic loading applied to a glass-fiber-reinforced hybrid composite resin on its flexural strength in a moist, simulated oral environment.
  
  
  METHODS
  Three-point flexural strength specimens were subjected to cyclic loading in water at 37°C and 55°C to investigate the influence of immersion temperature on impact fatigue properties. Specimens were subjected to cyclic impact loading at 1 Hz for up to 5 × 105 cycles to obtain the number of cycles to failure, the number of unbroken specimens after 5 × 105 cycles, and the residual flexural strength of unbroken specimens. Maximum loads of 100, 200, and 300 N were chosen for both the non-reinforced and the glass-fiber reinforced hybrid composite resins.
  
  
  RESULTS
  The mean residual flexural strength for 100 N impact loading at temperatures of 37°C and 55°C was 634 and 636 MPa, respectively. All specimens fractured at fewer than 5 × 105 cycles for loads of 200 and 300 N.
  
  
  CONCLUSIONS
  Reduced numbers of cycles to fracture and lower fatigue values were observed as both the maximum load and immersion temperature increased.
authors.affiliation: Department of Crowns and Bridges, The Nippon Dental University, School of Life Dentistry at Tokyo, Chiyoda-ku, Japan. akiyoshi047@yahoo.co.jp
authors.forename: Soichi
authors.initials: S
authors.lastname: Kuroda
authors.forename: Akikazu
authors.initials: A
authors.lastname: Shinya
authors.forename: Pekka K
authors.initials: PK
authors.lastname: Vallittu
authors.forename: Yuji
authors.initials: Y
authors.lastname: Nakasone
authors.forename: Akiyoshi
authors.initials: A
authors.lastname: Shinya
mesh_terms: D003188:Composite Resins / Q000737:chemistry; D003799:Dental Stress Analysis; D005898:Glass; D006358:Hot Temperature; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D018583:Pliability; D011140:Polyurethanes / Q000737:chemistry; D014867:Water
chemical_list: D003188:Composite Resins; D008689:Methacrylates; D011140:Polyurethanes; C009753:fiberglass; C091839:urethanetrimethacrylate; D014867:Water