title: Water sorption and dimensional stability of three glass fiber-reinforced composites.
abstract: OBJECTIVE
  Water sorption and dimensional stability of three fiber-reinforced composites were studied. Two composites (Vectris, FibreKor) were resin impregnated industrially, and one composite (Stick) was polymer preimpregnated but required further manual impregnation.
  
  
  METHODS
  Bar-shaped specimens of each material were prepared according to manufacturers' instructions. The water sorption and dimensional change of each specimen were calculated according to the change in its weight and dimension before and after immersion. Specimens were immersed in distilled water for 1, 7, 60, and 180 days. SEMs were taken to examine the quality of the fiber-matrix interface. The volume percentage of fiber content of each fiber-reinforced composite was experimentally estimated.
  
  
  RESULTS
  A general trend of increasing water sorption for each immersion period according to the material type was: Vectris < FibreKor < Stick. There were no significant differences in dimensional change among the materials and immersion periods.
  
  
  CONCLUSIONS
  The preimpregnated fiber-reinforced composite (Stick) showed higher water sorption than the industrially impregnated fiber-reinforced composites (Vectris, FibreKor). Despite a variation in the water sorption of the fiber-reinforced composites studied, all were within a 32 microg/mm3 criterion established by the ISO. The magnitude of dimensional change was small enough that it should not raise any significant clinical concern.
authors.affiliation: Northwestern University, Chicago, USA. jchai@northwestern.edu
authors.forename: John
authors.initials: J
authors.lastname: Chai
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Takahashi
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Hisama
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Shimizu
mesh_terms: D000042:Absorption; D000704:Analysis of Variance; D003188:Composite Resins / Q000737:chemistry*; D003890:Desiccation; D005898:Glass; D008422:Materials Testing; D019904:Polymethyl Methacrylate / Q000737:chemistry; D018709:Statistics, Nonparametric; D014867:Water / Q000737:chemistry; D017155:Wettability
chemical_list: D003188:Composite Resins; C113550:FiberKor, sculpture; C485628:Stick resin; C485630:Vectris Pontic; C009753:fiberglass; D014867:Water; D019904:Polymethyl Methacrylate