title: Effect of 180-week water storage on the flexural properties of E-glass and silica fiber acrylic resin composite.
abstract: OBJECTIVE
  The aim of this study was to determine the effect of long-term water immersion on the flexural properties of fiber-reinforced composite.
  
  
  METHODS
  Continuous, woven, silanized E-glass fibers and woven silica fibers were used to reinforce heat-cured and autopolymerized denture base polymers. Fibers were oriented at a 45-degree angle to the long axis of the test specimens. Control specimens were unreinforced. Dry test specimens and those stored in water for up to 180 weeks were tested with a 3-point loading apparatus.
  
  
  RESULTS
  Ultimate transverse strength and flexural modulus of unreinforced and fiber-reinforced composite test specimens decreased during water storage (P < 0.001, analysis of variance). Post hoc analysis revealed that after the storage of 4 weeks no statistically significant reduction occurred.
  
  
  CONCLUSIONS
  The results of this study suggest that the ultimate transverse strength of the fiber-reinforced composite made from E-glass fibers is reduced by approximately 27% compared to the dry fiber-reinforced composite. The majority of the reduction occurred during 4 weeks of storage in water and remained approximately at that level for 180 weeks.
authors.affiliation: Department of Prosthetic Dentistry and Biomaterials Project, Institute of Dentistry, University of Turku, Lemminkäisenkatu 2, FIN-20520 Turku, Finland. pekka.vallittu@utu.fi
authors.forename: P K
authors.initials: PK
authors.lastname: Vallittu
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D003819:Denture Bases; D004356:Drug Storage; D004548:Elasticity; D005898:Glass / Q000737:chemistry; D008422:Materials Testing; D018583:Pliability; D012822:Silicon Dioxide / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D000180:Acrylic Resins; C009753:fiberglass; D014867:Water; D012822:Silicon Dioxide