title: Flexural properties of the bulk fiber-reinforced composite DC-tell used in fixed partial dentures.
abstract: OBJECTIVE
  The aim of this study was to measure the flexural properties of fiber-reinforced composite (FRC) used in frameworks of fixed partial dentures. In addition, the influence of water storage on the properties was determined.
  
  
  METHODS
  Rhombic test specimens for four groups were milled from bulk FRC material DC-Tell. The test specimens of the first group were stored and tested dry. In the second group, the test specimens were water stored for 3 months at 37 +/- 1 degrees C and tested in water. The specimens of the third group were also water stored, but they were tested dry at room temperature. Water-stored test specimens of the fourth group were dehydrated and tested dry at room temperature. A three-point bending test was used to measure the flexural properties. The quantity of glass fibers in the test specimens was determined by combustion analysis. Water uptake was calculated after 3 months of water immersion. The direction and length of fibers were examined, and elemental composition was determined.
  
  
  RESULTS
  Water storage decreased the flexural strength by 66% and flexural modulus by 60%. After dehydration, the flexural strength did not recover to the same level as the flexural strength of the dry-group specimens. The fiber content was 38% by volume. Water uptake was 3 wt%. The reinforcement of DC-Tell was short fibers in random orientation, and the elemental composition of fibers was similar to that of E-glass.
  
  
  CONCLUSIONS
  Water storage decreases the flexural properties of the bulk fiber-reinforced composite DC-Tell. This may restrict the use of DC-Tell as a framework of crowns and bridges in the oral cavity in the long term.
authors.affiliation: Biomaterials Research, University of Turku, Finland.
authors.forename: T M
authors.initials: TM
authors.lastname: Lastumäki
authors.forename: L V
authors.initials: LV
authors.lastname: Lassila
authors.forename: P K
authors.initials: PK
authors.lastname: Vallittu
mesh_terms: D000704:Analysis of Variance; D003188:Composite Resins / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D003830:Denture, Partial, Fixed; D003890:Desiccation; D004548:Elasticity; D004577:Electron Probe Microanalysis; D005898:Glass / Q000737:chemistry; D006801:Humans; D007101:Immersion; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D009757:Nylons / Q000737:chemistry*; D018583:Pliability; D013223:Statistics as Topic; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D003188:Composite Resins; C448679:DC-tell; D003764:Dental Materials; D009757:Nylons; C009753:fiberglass; D014867:Water