Shear bond strength of one-bottle dentine bonding systems.

The purpose of this in vitro study was to determine the shear bond strength (SBS) of composite resin to human, buccal dentine, using four one-bottle dentine bonding systems. Eighty recently extracted human molar teeth were embedded in metal rings by means of self-curing acrylic resin. The projecting buccal surfaces were ground wet on 600 grit silicone carbide paper in order to expose superficial dentine. The teeth were randomly divided into four groups (N=20): 1=Prime&tBond 2.1 (PB, Dentsply); 2=Scotchbond 1 (SB, 3M); 3=Optibond Solo (OS, Kerr) and 4=Syntac Single Component (SY, Vivadent). The dentine surfaces were etched, treated with one of the four dentine bonding systems, and cylinders of matching composites were then bonded to the surfaces by means of a silicone rubber split mould. All specimens were stored for 24 hours under water at 37 degrees C. The bonds were then stressed to failure with an Instron testing machine, operating at a crosshead speed of 0.5 mm/min. The data were statistically analysed (Kruskall-Wallis). The mean SBS (MPa) were: PB = 12.5 +/- 2.0; SB = 16.2 +/- 1.9; OS = 17.4 +/- 3.1 and SY= 8.1 +/- 1.9. There was a statistically significant difference (P = 0.0001) between the mean of SY and the other 3 groups, and also between PB and the other groups. There was no statistically significant difference (P = 0.244) between the SBS of OS and SB. SY demonstrated the lowest SBS.