Aim:To clinically evaluate and compare cavity preparation with Erbium:Yttrium Aluminum Garnet (Er:YAG) laser bonded with 5th and 7th generation bonded agent restoration with composite resin at 3 months, 6 months and 12 months. Materials and Methods: 40 patients with class I cavity preparation were bonded with 5th generation bonding agent formed group 1 and 40 Patients with class I cavity preparation were bonded with 7th generation bonding agent formed group 2. Patients included had primary proximal carious lesions in posterior teeth 2. 2.1 and 2.2 according to G.J. Mount classification. Cavity preparation was done using Er:YAG laser. Incremental technique of no more than 2mm for inserting composites was used. Evaluation was done using Ryge’s criteria. Results: No significant difference was observed between clinical performances of the two materials at 3 months. (p>0.05) At 6 months, statistically significant difference was seen with marginal adaptation, secondary caries and post-operative sensitivity. (p<0.05) At 12 months, the post-operative sensitivity was seen to be more with 5th generation bonding agent than the 7th generation. Conclusion: The composite resin restorations with 7th generation bonding agents showed a lesser degree post-operative sensitivity and secondary caries, as compared to those with 5th generation bonding agents.