Method: Flat enamel surfaces were prepared on primary teeth. Composite resin samples (Z100® A2 shade) were bonded using two systems: Singlebond® (SB) and Adper Easy One® (AEO) and Adper Easy One® with previous acid etching (AEOG). Three groups were conformed according to conditioning system used. Cylindrical composite resin samples 3 x 8 mm were prepared and stored in distilled water for 24 hours at 37°C. Shear bond strength was determined by means of a Universal Testing Machine (Instron Corporation). Data obtained were analyzed using ANOVA and Tukey test from SPSS 19.0®. p value was established at 0,05
Results: Mean and standard deviation (MPa) for shear bond strength recorded for each group were: SB 14.5 (4.40); AEO 4.03 (2.38) and AEOG 14.99 (1.65). ANOVA showed significant differences (p<0.05) and Tukey test showed two homogeneous groups with SB and AEOG in one and AEO on the other. Systems with independent acid etching showed values significantly higher than self conditioning systems
Conclusion: Previous conditioning of substrate in primary enamel improves shear bond strength disregarding of bonding system used