title: Evaluation of some properties of two fiber-reinforced composite materials.
abstract: OBJECTIVE
  Water sorption, flexural properties, bonding properties, and elemental composition of photopolymerizable resin-impregnated fiber-reinforced composite (FRC) materials (everStick C&B and BR-100) (FPD) were evaluated in this study.
  
  
  METHODS
  Bar-shaped specimens (2 x 2 x 25 mm) were prepared for water sorption and flexural strength testing. The specimens (n = 6) were polymerized either with a hand light-curing unit for 40 s or, additionally, in a light-curing oven for 20 min and stored in water for 30 days. Water sorption was measured during this time, followed by measurements of flexural strength and modulus. A shear bond strength test was performed to determine the bonding characteristics of polymerized FRC to composite resin luting cement (Panavia-F), (n = 15). The cement was bonded to the FRC substrate and the specimens were thermocycled 5000 times (5-55 degrees C) in water. SEM/EDS were analyzed to evaluate the elemental composition of the glass fibers and the fiber distribution in cross section.
  
  
  RESULTS
  ANOVA showed significant differences in water sorption according to brand (p < 0.05). Water sorption of everStick C&B was 1.86 wt% (hand-unit polymerized) and 1.94 wt% (oven polymerized), whereas BR-100 was 1.07 wt% and 1.17 wt%, respectively. The flexural strength of everStick C&B after 30 days' water storage was 559 MPa (hand-unit polymerized) and 796 MPa (oven-polymerized); for BR-100, the values were 547 MPa and 689 MPa, respectively. Mean shear bond strength of composite resin cement to the FRC varied between 20.1 and 23.7 MPa, showing no statistical difference between the materials. SEM/EDS analysis revealed that fibers of both FRC materials consist of the same oxides (SiO2, CaO, and Al2O3) in ratios. The distribution of fibers in the cross section of specimens was more evenly distributed in everStick C&B than in BR-100.
  
  
  CONCLUSIONS
  The results of this study suggest that there are some differences in the tested properties of the FRC materials.
authors.affiliation: Department of Prosthetic Dentistry and Biomaterials Research, Institute of Dentistry, University of Turku, Turku, Finland. lippo.lassila@utu.fi
authors.forename: Lippo V J
authors.initials: LV
authors.lastname: Lassila
authors.forename: Arzu
authors.initials: A
authors.lastname: Tezvergil
authors.forename: Milla
authors.initials: M
authors.lastname: Lahdenperä
authors.forename: Pasi
authors.initials: P
authors.lastname: Alander
authors.forename: Akiyoshi
authors.initials: A
authors.lastname: Shinya
authors.forename: Akikazu
authors.initials: A
authors.lastname: Shinya
authors.forename: Pekka K
authors.initials: PK
authors.lastname: Vallittu
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry; D017610:Calcium Compounds / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding; D004548:Elasticity; D004577:Electron Probe Microanalysis; D005898:Glass / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D010087:Oxides / Q000737:chemistry; D018583:Pliability; D011140:Polyurethanes / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D033081:Shear Strength; D012822:Silicon Dioxide / Q000737:chemistry; D013499:Surface Properties; D014867:Water / Q000737:chemistry
chemical_list: C505390:BR 100; D017610:Calcium Compounds; C438313:Clearfil SE Bond; D003188:Composite Resins; D008689:Methacrylates; D010087:Oxides; C438843:Panavia-Fluoro; D011140:Polyurethanes; D019279:Resin Cements; C496140:everStick; C009753:fiberglass; C404582:urethane tetramethacrylate; D014867:Water; D012822:Silicon Dioxide; C016538:lime; D000537:Aluminum Oxide