title: Flexural Strength of Cold and Heat Cure Acrylic Resins Reinforced with Different Materials.
abstract: OBJECTIVE
  Heat-polymerized acrylic resin has been the most commonly used denture base material for over 60 years. However, the mechanical strength of acrylic resin is not adequate for long-term clinical performance of dentures. Consequently, fracture is a common clinical occurrence, which often develops in the midline of the denture base. This study aimed to evaluate the efficacy of cold-cure and heat-cure acrylic resins, reinforced with glass fibers, polyethylene fibers, and metal wire for denture base repair.
  
  
  METHODS
  Ninety specimens were prepared and allocated to nine groups. Ten specimens were considered as controls, and 80 were divided into 8 experimental groups. In the experimental groups, the specimens were sectioned into two halves from the middle, and were then divided into two main groups: one group was repaired with heat cure acrylic resin, and the other with cold cure acrylic resin. Each group was divided into 4 subgroups: unreinforced, reinforced with glass fibers, polyethylene fibers, and metal wire. All specimens were subjected to a 3-point bending test, and the flexural strength was calculated.
  
  
  RESULTS
  The group repaired with heat cure acrylic resin and reinforced with glass fiber showed the highest flexural strength; however, the group repaired with cold cure acrylic resin and reinforced with polyethylene fibers had the lowest flexural strength. There was no significant difference between the groups repaired with heat cure and cold cure acrylic resins without reinforcement.
  
  
  CONCLUSIONS
  Repairing denture base with heat cure acrylic resin, reinforced with glass fibers increases the flexural strength of denture base.
authors.affiliation: Assistant Professor, Department of Prosthodontic Dentistry, Hamadan University of Medical Sciences, Hamadan, Iran.
authors.forename: Bijan
authors.initials: B
authors.lastname: Heidari
authors.affiliation: Assistant Professor, Department of Prosthodontic Dentistry, Hamadan University of Medical Sciences, Hamadan, Iran.
authors.forename: Farnaz
authors.initials: F
authors.lastname: Firouz
authors.affiliation: Assistant Professor, Department of Prosthodontic Dentistry, Hamadan University of Medical Sciences, Hamadan, Iran.
authors.forename: Alireza
authors.initials: A
authors.lastname: Izadi
authors.affiliation: Private Practice, Hamadan, Iran.
authors.forename: Shahbaz
authors.initials: S
authors.lastname: Ahmadvand
authors.affiliation: Postgraduate Student, Department of Prosthodontic Dentistry, Hamadan University of Medical Sciences, Hamadan, Iran.
authors.forename: Pegah
authors.initials: P
authors.lastname: Radan
keywords: Acrylic resins; Denture repair; Reinforcement; Strength