The purpose of this study was to determine and compare the shear bond strength of a conventional glassionomer
cement, a resin modified glass-ionomer, a composite resin and three compomer restorative
materials. Dentin of the occlusal surfaces from sixty extracted human permanent molars were prepared
for shear bond strength testing. The specimens were randomly divided into six groups of 10 each. Dentinal
surfaces were treated according to the instructions of manufacturers for each material. Each restorative
material was placed inside nylon cylinders 2 mm high with an internal diameter of 3 mm, which were
placed perpendicular to dentin surfaces. Shear bond strengths were determined using an Universal Testing
Machine at crosshead speed of 0.5 mm/min in a compression mode. Conventional glass-ionomer,
Ketac-Molar aplicap showed the lowest mean shear bond strength 3.77 ± 1.76 (X ± SD MPa) and the
composite resin, Heliomolar showed the highest mean shear bond strength 16.54 ± 1.65 while the mean
bond strength of Fuji II LC was 9.55 ± 1.06. The shear bond strengths of compomer restorative materials
were 12.83 ± 1.42, 10.64 ± 1.42 and 11.19 ± 1.19 for Compoglass, Hytac and Dyract respectively.
ANOVA revealed statistically significant differences in the mean shear bond strengths of all groups
(P<0.001). No statistically significant difference was found between the three compomer materials
(P>0.5). Ketac-Molar and composite resin showed statistically significant difference (P<0.0005). The
mode of fracture varied between materials. It is concluded that the compomer restorative materials show
higher shear bond strength than conventional glass-ionomer and resin modified glass-ionomer, but less
than composite resin. The fracture mode is not related to the shear bond strengths values.