Effect of ridge lap surface treatment and thermocycling on microtensile bond strength of acrylic teeth to denture base resins.

This study evaluated the effect of denture base polymer type (heat- and microwave-polymerized), ridge lap surface treatment (with and without methyl methacrylate-MMA etching) and thermocycling on the microtensile bond strength (microTBS) of Biotone acrylic teeth. Flat-ground, ridge-lap surface of posterior artificial teeth were bonded to cylinders of each denture base resin, resulting in the following groups (n=6): G1a - Clássico/with MMA etching; G1b - Clássico/without MMA etching; G2a - OndaCryl/with MMA etching; G2b - OndaCryl/without MMA etching. Rectangular bar specimens with a cross-sectional area of 1 mm(2) were prepared. Half of the bars in each group were thermocycled (5,000 cycles between 4 degrees C and 60 degrees C). microTBS testing was performed in an universal testing machine at a crosshead speed of 0.5 mm/min. Data were analyzed statistically by three-way ANOVA (alpha=0.05). There was no statistically significant difference (p>0.05) for the factors (resin, surface treatment,and thermocycling) or their interactions. The mean microTBS values (MPa) and standard deviations were as follows: Thermocycling - G1a: 41.00 (14.00); G1b: 31.00 (17.00); G2a: 50.00 (27.00); G2b: 40.00 (18.00); No thermocycling - G1a: 37.00 (14.00); G1b: 43.00 (25.00); G2a: 43.00 (14.00); G2b: 40.00 (27.00). The microTBS of Biotone artificial teeth to the denture base acrylic resins was not influenced by the polymer type, surface treatment or thermocycling.