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Introduction: Majority of composites previously available were of universal hybrid or microhybrid resin containing glass filler particles around or less than 1 μm and colloidal silica. Polymerisation shrinkage of composites leading to inadequate marginal seal at tooth-restoration interface have been one major disadvantage of its applicability.  Recently introduced nanofilled resin composites contain filler particle size of 0.1-100 nm consequently reducing polymerisation shrinkage. Measurement of shear bond strength of composite-tooth interface is one of the factors to determine adhesion between dental hard tissue and the composite.

Objective: The objective of this study was to investigate the difference in shear bond strength of nanocomposites and microhybrid composites.

Materials and Method: An in vitro comparative evaluation of shear bond strength of nanocomposites with a microhybrid composite was conducted. The buccal surfaces of the 20 teeth were acid etched and rinsed with water and air-dried. Posts were prepared of the restorative materials (Z100 and Filtek Supreme Z350) on smoothened buccal surface of the respective groups consisting of 10 teeth measuring 3 mm diameter and 2 mm depth using plastic templates. The samples were tested in the Instron Universal Tesing Machine.

Result: The mean value of the shear  bond strength of both the materials were found to be  similar (15.67 MPa) and there was no statistical difference between the two groups.

Conclusion: The shear bond strength using a single bonding agent, were same in both the materials which did not show disparity in the adhesive capacity in the two groups.

Keywords: microhybrid composite; nanocomposites; shear bond strength.