Aim: This clinical study was conducted to compare the clinical effectiveness of using a hand instrument (OptraContact, Ivoclar Vivadent, USA) in conjunction with the sectional matrix (Palodent, DENTSPLY Sirona, USA) when applying lateral forces at the contact area during curing versus using sectional matrix system (Palodent) alone to achieve a tight proximal contact in posterior teeth. Materials and Methods: The study design was two arms, parallel-group, randomized, controlled trial. The study was conducted on 46 participants with class II carious lesions. The participants were divided into 2 groups; Group (1): the prepared cavities were restored using Palodent sectional matrix system in conjunction with OptraContact. Group (2): the prepared cavities were restored using Palodent sectional matrix system. The teeth were restored using universal adhesive system and nanohybrid resin composite. The proximal contact tightness was tested at baseline, after 3 and 6 months using dental floss and using Modified USPHS Ryge criteria

class II carious lesions, class II resin composite, proximal contact tightness, Palodent matrix system, sectional matrix system, OptraContact instrument