Materials and Methods: Thirty extracted carious human molars were assigned to two groups according to adhesive used i.e Adper Single Bond (Total etch) with P90 (Self-etch). The occlusal surface of teeth will be sectioned to expose dentin and built up with Filtek 90 composite (3M) to a 3 mm height. The teeth were then sectioned to obtain rods of 6mm length and 1mm width and 1 mm depth with dentin-composite interface located at the centre. The specimens were examined under microscope to separate caries–affected dentin and unaffected dentin into two groups. Half the specimens from each group were subjected to 3000 thermo cycles (5 deg Celsius to 55 deg Celsius). All specimens were subjected to microtensile bond strength testing in a special apparatus attached to the Universal testing machine. Results were recorded and data was statistically analyzed with Students unpaired ‘t’ test.

Results: Students ‘t’ test showed that the values had a statistically significant difference observed between total etch (T.E) i.e. Adper Single Bond 2 and self etch (S.E) i.e. P 90; caries-affected dentin (CAD) and normal dentin (ND); with thermocycling and without thermocycling.

Interpretation and Conclusion: The present study concludes that total-etch has a higher bond strength compared to self-etch. Bond strengths are higher to normal dentin than caries-affected dentin. Thermocycling lowers the bond strength values of all the groups.