Shear bond strength and microleakage of new dentin bonding systems

The aim of this study was to evaluate the shear bond strength and microleakage of three new bonding agents. Eight specimens were prepared from each material and shear bond strength was measured using a universal testing machine at crosshead speed of 0.5 mm/minute. Fracture pattern was studied by stereomicroscope and scanning electron microscope (SEM). For the microleakage test, Class V cavities were prepared in the buccal or lingual surface of extracted lower molar teeth and restored with resin composites after application of the accompanying adhesives. The restored teeth were loaded at 125 N for 5000 cycles in a dye solution, sectioned and inspected for microleakage. Bond strengths of 17.7 +/- 4.1, 16.3 +/- 3.8, 15.7 +/- 5.8 MPa were measured for Scotchbond Multi-Purpose, Clearfil Liner Bond and Optibond respectively. Restorations of Scotchbond MP and Clearfil LB showed no leakage, while those of OptiBond showed leakage in only one out of eight fillings.