Objective: To assess the effect of horizontal incremental application on the cuspal strain profile thatoccurs when restoring premolar teeth with low-shrinkage and methacrylate-based resin compositerestorative materials.Methods: Twenty freshly extracted sound human maxillary second premolar teeth were selected andstandardized MOD cavities were prepared. The teeth were divided into two groups (n=10) accordingto the material used either Filtek™ Z250 (3M ESPE, USA) or Filtek™ P90 (3M ESPE, USA). Eachrestoration was applied in four successive horizontal increments. Cuspal strain profile was calculatedby measuring the intercuspal distance between the indexed cusp tips before the restorative procedureand after light-curing of each increment using a stereo-microscope connected to a digital camera andimage analysis software to detect the cuspal deflection.Results: Results revealed that Filtek™ P90 exhibited lower cuspal strain profile than Filtek™ Z250when applied in four horizontal increments.Conclusion: The low-shrinkage resin composite restorative material had a positive effect oncontrolling the cuspal strain profile more than the conventional methacrylate-based resin compositerestorative material.