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.
Materials and 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).
Conclusion: 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.