Influence of Surface Treatment on Resin Composite -PMMA bond strength

Objective: Evaluate the influence of surface treatment of the self-cured polymetil methacrilate (PMMA) in bond strength to composite resin. Methods: Were fabricated six PMMA blocks with dimensions of 20mm x 10mm x 4mm. The materials used for surface treatment were: milling Maxicut (BR); Single Bond 2 (AD); Silano RelyX Ceramic Primer (SIL) and Phosphoric Acid 35% (AC). Surface treatments applied were: G1 (BR + AC + AD); G2 (AC + AD); G3 (AD); G4 (AC + AD + SIL); G5 (SIL + AD) and G6 (U.S. + CA + SIL + AD). The blocks were restored with two increments of composite 2mm 4 Seasons A1 and photoactivated by light emitting diode as recommended by the manufacturer. These were stored in artificial saliva for 24 hours. After, sectioned to obtain sticks with dimensions of 0.9 mm x 0.9 mm (n = 20). Results were recorded in Mega Pascals (Mpa). Data were analysed statistically by analysis of variance (ANOVA) with one factor and a detailed analysis through the test of Tukey HSD and Dunnett (ρ ≤ 0.05). Results: The mean (± SD) were: G1 = 35.86 ± 7.3 A; G2 = 29.00 ± 6.4 AB; G3 = 32.37 ± 10.6 AB; G4 = 27.65 ± 9.6 B; G5 = 27.67 ± 5B and G6 = 26.51 ± 5.6 B. Conclusion: The surface treatment of PMMA proved to be essential to obtain higher values of bond strength to composite resin.