title: A comparison of the fitting accuracy of thermoplastic denture base resins used in non-metal clasp dentures to a conventional heat-cured acrylic resin.
abstract: OBJECTIVE
  To incorporate a metal framework into removable partial dentures, the dimensional accuracy of thermoplastic resins requires precision equivalent to conventional acrylic resins. This study aimed to evaluate the fitting accuracy of thermoplastic resins compared to heat-cured acrylic resin.
  
  
  METHODS
  Four thermoplastic resins (polyethylene terephthalate [EstheShot, ES; EstheShot Bright, ES-B], polyamide [Lucitone FRS, LF], polycarbonate [Reigning Resin N, RN] and a heat-curing acrylic resin [Acron, AC]) were used. The specimens were created on master casts constructed of high-strength stone that simulated a maxillary edentulous ridge. Additionally, high-expansion stone was used as the master cast for RN specimens. The ES-B, LF and RN specimens were prepared with and without annealing after injection molding. The gaps between the molded resin and the cast were measured.
  
  
  RESULTS
  ES had the smallest gap and was significantly smaller than AC (p < 0.05). The gap sizes of ES-B, LF and RN (high-expansion stone) without annealing were similar to AC (p > 0.05), while the gap size of RN (high-strength stone) with and without annealing was significantly greater than AC (p < 0.001). The gap sizes of ES-B and LF with annealing were significantly less than AC (p < 0.05). Further, the gap sizes of ES-B, LF and RN with annealing were significantly smaller than the gaps without annealing (p < 0.05).
  
  
  CONCLUSIONS
  The results suggested that ES, ES-B and LF have adequate fitting accuracy for incorporating metal framework into dentures and that annealing effectively improved the fitting accuracy of ES-B, LF and RN.
authors.affiliation: Section of Removable Partial Prosthodontics, Department of Masticatory Function Rehabilitation, Graduate School of Medical and Dental Sciences.
authors.forename: Junichiro
authors.initials: J
authors.lastname: Wada
authors.forename: Kenji
authors.initials: K
authors.lastname: Fueki
authors.forename: Masaru
authors.initials: M
authors.lastname: Yatabe
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Takahashi
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Wakabayashi
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D003722:Dental Alloys / Q000737:chemistry; D018772:Dental Marginal Adaptation; D003764:Dental Materials / Q000737:chemistry*; D003819:Denture Bases; D003779:Denture Design; D003832:Denture, Partial, Removable; D006358:Hot Temperature; D006801:Humans; D008422:Materials Testing; D003765:Models, Dental; D009757:Nylons / Q000737:chemistry; D011076:Polycarboxylate Cement / Q000737:chemistry; D011093:Polyethylene Terephthalates / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D019904:Polymethyl Methacrylate / Q000737:chemistry; D013450:Sulfones / Q000737:chemistry; D013499:Surface Properties
chemical_list: D000180:Acrylic Resins; D003722:Dental Alloys; D003764:Dental Materials; D009757:Nylons; D011076:Polycarboxylate Cement; D011093:Polyethylene Terephthalates; D011108:Polymers; D013450:Sulfones; C005506:polycarbonate; C040291:Lucitone; C045672:Reigning resin; D019904:Polymethyl Methacrylate
keywords: denture base; fitting accuracy; removable partial denture; thermoplastic resin