title: The Effect of Polymerization Methods and Fiber Types on the Mechanical Behavior of Fiber-Reinforced Resin-Based Composites.
abstract: OBJECTIVE
  Glass fibers were introduced to increase the fracture resistance of resin-based composites restorations; however, the poor polymerization between fibers and resin-based composite were sometimes noted and can cause debonding and failure. The purpose of this study was to investigate the effects of different polymerization methods as well as fiber types on the mechanical behavior of fiber-reinforced resin-based composites.
  
  
  METHODS
  Seventy-five specimens were fabricated and divided into one control group and four experimental groups (n = 15), according to the type of glass fiber (strip or mesh) and polymerization methods (one- or two-step). A 0.2-mm-thick fiber layer was fabricated with different polymerization methods, on top of which a 1.8 mm resin-based composite layer was added to make a bar-shape specimen, followed by a final polymerization. Specimens were tested for flexural strength and flexural modulus. The failure modes of specimens were observed by scanning electron microscopy.
  
  
  RESULTS
  The fiber types showed significant effect on the flexural strength of test specimens (F = 469.48, p < 0.05), but the polymerization methods had no significant effect (F = 0.05, p = 0.82). The interaction between these two variables was not significant (F = 1.73, p = 0.19). In addition, both fiber type (F = 9.71, p < 0.05) and polymerization method (F = 12.17, p < 0.05) affected the flexural modulus of test specimens; however, the interaction between these two variables was not significant (F = 0.40, p = 0.53).
  
  
  CONCLUSIONS
  The strip fibers showed better mechanical behavior than mesh fibers and were suggested for resin-based composites restorations reinforcement; however, different polymerization methods did not have a significant effect on the strength and failure mode of fiber-reinforced resin-based composites.
authors.affiliation: Department of Restorative Dentistry, University of Detroit Mercy School of Dentistry, Detroit, MI.
authors.forename: Nan-Chieh
authors.initials: NC
authors.lastname: Huang
authors.affiliation: Department of Biomedical and Applied Sciences, Indiana University School of Dentistry, Indianapolis, IN.
authors.forename: Marco C
authors.initials: MC
authors.lastname: Bottino
authors.affiliation: Department of Restorative Dentistry, Indiana University School of Dentistry, Indianapolis, IN.
authors.forename: John A
authors.initials: JA
authors.lastname: Levon
authors.affiliation: Department of Biomedical and Applied Sciences, Indiana University School of Dentistry, Indianapolis, IN.
authors.forename: Tien-Min G
authors.initials: TG
authors.lastname: Chu
mesh_terms: D003188:Composite Resins / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D003799:Dental Stress Analysis; D055119:Elastic Modulus; D005898:Glass / Q000737:chemistry*; D066298:In Vitro Techniques; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D058105:Polymerization; D013314:Stress, Mechanical; D013499:Surface Properties
chemical_list: D003188:Composite Resins; D003764:Dental Materials; C009753:fiberglass
keywords: Flexural strength; fiber-reinforced composites; glass fibers; polymerization