title: Evaluation of the bond strength of denture base resins to acrylic resin teeth: effect of thermocycling.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the thermocycling effects and shear bond strength of acrylic resin teeth to denture base resins.
  
  
  METHODS
  Three acrylic teeth (Biotone, Trilux, Ivoclar) were chosen for bonding to four denture base resins: microwave-polymerized (Acron MC), heat-polymerized (Lucitone 550 and QC-20), and light-polymerized (Versyo.bond). Twenty specimens were produced for each denture base/acrylic tooth combination and were divided into two groups (n = 10): without thermocycling (control groups) and thermocycled groups submitted to 5000 cycles between 4 and 60 degrees C. Shear strength tests (MPa) were performed with a universal testing machine at a crosshead speed of 1 mm/min. Statistical analysis of the results was carried out with three-way ANOVA and Bonferroni's multiple comparisons post hoc analysis for test groups (alpha = 0.05).
  
  
  RESULTS
  The shear bond strengths of Lucitone/Biotone, Lucitone/Trilux, and Versyo/Ivoclar specimens were significantly decreased by thermocycling, compared with the corresponding control groups (p < 0.05). The means of Acron/Ivoclar and Lucitone/Ivoclar specimens increased after thermocycling (p < 0.05). The highest mean shear bond strength value was observed with Lucitone/Biotone in the control group (14.54 MPa) and the lowest with QC-20/Trilux in the thermocycled group (3.69 MPa).
  
  
  CONCLUSIONS
  Some acrylic tooth/denture base resin combinations can be more affected by thermocycling; effects vary based upon the materials used.
authors.affiliation: Department of Dental Materials and Prosthodontics, Araraquara Dental School, São Paulo State University-UNESP, São Paulo, Brazil.
authors.forename: Juliê
authors.initials: J
authors.lastname: Marra
authors.forename: Raphael Freitas
authors.initials: RF
authors.lastname: de Souza
authors.forename: Debora Barros
authors.initials: DB
authors.lastname: Barbosa
authors.forename: Ana Carolina
authors.initials: AC
authors.lastname: Pero
authors.forename: Marco Antonio
authors.initials: MA
authors.lastname: Compagnoni
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D001840:Dental Bonding / Q000379:methods*; D003764:Dental Materials / Q000737:chemistry*; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D003819:Denture Bases; D006801:Humans; D033081:Shear Strength; D013696:Temperature; D014093:Tooth, Artificial
chemical_list: D000180:Acrylic Resins; D003764:Dental Materials