title: Effect of Reinforcement on the Flexural Properties of Injection-Molded Thermoplastic Denture Base Resins.
abstract: OBJECTIVE
  To evaluate the effect of reinforcement on the flexural properties of injection-molded thermoplastic denture base resins.
  
  
  METHODS
  Three injection-molded thermoplastic denture base resins (polyamide, polyester, polycarbonate) were selected for this study, and a conventional heat-polymerized denture base resin (PMMA) was used as a control. Continuous unidirectional glass fiber-reinforced composite (FRC) and metal wire were used for reinforcement. Reinforced bar-shaped specimens (65 mm long, 10 mm wide, 3.3 mm high) were fabricated (n = 10). The flexural strength at the proportional limit (FS-PL) and the elastic modulus were measured using a three-point bending test.
  
  
  RESULTS
  All the denture base material specimens reinforced with FRC possessed a significantly higher FS-PL compared to those without reinforcement. The FS-PL of the polycarbonate specimens reinforced with metal wire was significantly higher than that without reinforcement, and there was no significant difference in the FS-PL between the polycarbonate specimens reinforced with FRC and those with metal wire. The order of the elastic modulus according to the denture base material, arranged in terms of statistical significance, was as follows: PMMA (3.46 ± 0.53 GPa) > polycarbonate (2.69 ± 0.48 GPa) > polyester (2.00 ± 0.39 GPa) > polyamide (1.14 ± 0.35 GPa). The order of the elastic modulus according to the reinforcement, arranged in terms of statistical significance, was as follows: metal wire (2.74 ± 0.96 GPa) > FRC (2.40 ± 0.89 GPa) > no reinforcement (1.82 ± 0.83 GPa).
  
  
  CONCLUSIONS
  Continuous unidirectional glass fiber-reinforced composite (FRC) reinforcement had a satisfactory reinforcing effect for the injection-molded thermoplastic denture base resins.
authors.affiliation: Division of Removable Prosthodontics, Fukuoka Dental College, Fukuoka, Japan.
authors.forename: Hirono
authors.initials: H
authors.lastname: Sasaki
authors.affiliation: Division of Removable Prosthodontics, Fukuoka Dental College, Fukuoka, Japan.
authors.forename: Ippei
authors.initials: I
authors.lastname: Hamanaka
authors.affiliation: Division of Removable Prosthodontics, Fukuoka Dental College, Fukuoka, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Takahashi
authors.affiliation: Division of Removable Prosthodontics, Fukuoka Dental College, Fukuoka, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Kawaguchi
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D003799:Dental Stress Analysis; D003819:Denture Bases; D003779:Denture Design; D055119:Elastic Modulus; D005898:Glass; D006801:Humans; D008422:Materials Testing; D013314:Stress, Mechanical
chemical_list: D000180:Acrylic Resins
keywords: Polyamide; fiber-reinforced composite; polycarbonate; polyester