title: Bond strength of denture teeth to acrylic resin: effect of thermocycling and polymerisation methods.
abstract: BACKGROUND
  Failure of bonding between acrylic resin teeth and denture base material is a considerable problem for patients who wear complete dentures.
  
  
  OBJECTIVE
  The purpose of this study was to evaluate the bond strength between acrylic resins and resin denture teeth with different thermocycling and polymerisation methods.
  
  
  METHODS
  Microwave-polymerised (Onda-Cryl), heat-polymerised (Clássico) and autopolymerising (Jet) acrylic resins and resin denture tooth (Biotone) were used. The acrylic resins were polymerised according to the following: (A) microwave - fast cycle, Onda-Cryl; (B) microwave - long cycle, Onda-Cryl; (C) microwave - manufacturer's cycle, Onda-Cryl; (T) water bath - long cycle, Clássico; and (Q) bench polymerisation cycle, Jet. Twenty specimens were prepared for each polymerisation method. Ten were thermocycled, and 10 did not receive thermocycling. For the purpose of the study, a shear test was used. Data were analysed with the Kruskal-Wallis test and Dunn's multiple comparisons test (p = 0.05).
  
  
  RESULTS
  Cycles B, C and T were similar (p > 0.05), and had statistically higher bonding values than cycles A and Q (p < 0.05) for the thermocycled and non-thermocycled groups. For all cycles, there were no statistically significant differences between thermocycled and non-thermocycled groups (p > 0.05), except for cycle Q (p = 0.0038).
  
  
  CONCLUSIONS
  Thermocycling decreased the bond strength, but not significantly for microwave and heat-polymerised cycles. Regarding the bond strength of denture teeth to acrylic resin, the fast microwave polymerisation cycle should be avoided when polymerising Onda-Cryl acrylic resin. In addition, Jet acrylic resin is not adequate for use in denture repair.
authors.affiliation: Department of Dental Materials and Prosthodontics, Araçatuba Dental School, São Paulo State University (UNESP), São Paulo, SP, Brazil. debora@foa.unesp.br
authors.forename: Debora Barros
authors.initials: DB
authors.lastname: Barbosa
authors.forename: Valentim Adelino Ricardo
authors.initials: VA
authors.lastname: Barão
authors.forename: Douglas Roberto
authors.initials: DR
authors.lastname: Monteiro
authors.forename: Marco Antonio
authors.initials: MA
authors.lastname: Compagnoni
authors.forename: Juliê
authors.initials: J
authors.lastname: Marra
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry* / Q000528:radiation effects; D000268:Adhesiveness; D003432:Cross-Linking Reagents / Q000737:chemistry / Q000528:radiation effects; D001840:Dental Bonding; D003764:Dental Materials / Q000737:chemistry* / Q000528:radiation effects; D003819:Denture Bases; D006358:Hot Temperature; D006801:Humans; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry / Q000528:radiation effects; D008768:Methylmethacrylates / Q000737:chemistry / Q000528:radiation effects; D008855:Microscopy, Electron, Scanning; D008872:Microwaves; D011108:Polymers / Q000737:chemistry / Q000528:radiation effects; D019904:Polymethyl Methacrylate / Q000737:chemistry / Q000528:radiation effects; D033081:Shear Strength; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D014093:Tooth, Artificial; D014867:Water / Q000737:chemistry
chemical_list: D000180:Acrylic Resins; D003432:Cross-Linking Reagents; D003764:Dental Materials; D008689:Methacrylates; D008768:Methylmethacrylates; D011108:Polymers; D014867:Water; C069716:Jet, dental resin; C004919:ethylene dimethacrylate; D019904:Polymethyl Methacrylate