Shear bond strength of a “solvent-free” adhesive versus contemporary adhesive systems

Aim: To compare the shear bond strength (SBS) of a solvent free self-etch adhesive with solvent containing adhesives. Methods: Forty-five human teeth were sectioned longitudinally to expose superficial dentin and substrates polished with 600-grit SiC paper. The adhesive area was isolated with a cylindrical Teflon mold 3x4 mm. Fifteen specimens were prepared for each material. Were evaluated a solvent free self-etch adhesive (Bond 1 SF), an ethanol self-etch adhesive (Futurabond M), and a water-acetone-ethanol self-etch adhesive (Optibond All-In-One). All specimens were subjected to an aging procedure by thermo-cycling (5000 cycles). Thirty-six specimens were stressed in shear at a rate of 0.5mm/min. Mean data values were analyzed statistically using the Welch robust analysis of variance and the Games-Howell statistic. Failure patterns were analyzed using stereomicroscope and scanning electron microscopy (SEM). Additional more dentin specimens were prepared for SEM. Results: The Bond 1 SF showed the statistically significant lowest SBS to dentin (Welch statistic p<0.001). Failures for Bond 1 SF were mainly adhesive failures with partial cohesive failures in the adhesive resin, while for Futurabond M and Optibond All-In-One were mainly mixed. SEM findings confirm the results. Conclusions: Eliminating solvents from self-etch adhesive systems may decrease the bonding strength to dentin.