Effect of Cavity Preparation Techniques on Bond Strength to Dentin

The bonding mechanism of current self-etching adhesive-systems depends on the superficial treatments by the cavity preparation techniques (CPT). Objectives: This study evaluated the effect of CPT on microtensile bond strength (µTBS) to dentin, using self-etching adhesive-systems (Clearfil SE Bond – Kuraray (SE) / Unifil Bond – GC Corp (UN)) and a total-etch adhesive-system (Single Bond – 3M ESPE (SB)). Methods: Oclusal dentin flattened of 45 third molars was treated with air-abrasion (AA), sonoabrasion (SA) and 600-grit SiC paper (SiC). Nine experimental groups were determined (n=4): G1: SE-AA, G2: SE-SA, G3: SE-SiC, G4: UN-AA, G5: UN-SA, G6: UN-SiC, G7: SB-AA, G8: SBSA, G9: SB-SiC. Following each surface treatment, adhesive-systems were applied according to manufacturer's instructions and 5mm high blocks were incrementally built up with Clearfil AP-X (Kuraray) composite-resin. The specimens were stored for 24hrs in distilled water and were serially sectioned in both “x” and “y” directions transversally to the bonded interface to obtain an array of bonded beams. Beams were tested in tension (0.5mm/min – Instron 4411) and results were analyzed by two-way ANOVA and Tukey's test (p<0.05). Results: SA produced higher µTBS and SB adhesive system was not influenced by superficial treatments (MPa): G1: 25.04±4.64Aa, G2: 14.11±5.48Ba, G3: 13.20±6.82Bb, G4: 32.31±9.20Aa, G5: 17.48±6.45Ba, G6: 11.24±4.62Bb, G7: 29.50±5.80Aa, G8: 21.92±4.94Aa, G9: 22.76±6.45Aa. Conclusion: The results showed that the cavity preparation technology can influence the microtensile bond strength to dentin for the self-etching adhesive systems.