One-Step Universal Adhesives: A 3-year Clinical Trial in Class II Composite Restorations

Inclusion Criteria: * Patients must present with at least four posterior primary compound proximal caries involving two surfaces, specifically occluso-mesial or occluso-distal cavities, with a corresponding International Caries Detection and Assessment System (ICDAS) score of 4 or 5. * The buccolingual width of the lesion should be approximately less than two-thirds of the intercuspal distance. * Teeth to be restored must be in normal occlusion with the natural antagonist teeth. * Vital teeth with no signs of pulpal inflammation or pathological lesions. * Normal periodontal status and good oral hygiene. * Good likelihood of recall availability. Exclusion Criteria: * Patients with proximal cavities that extend beyond two surfaces or have a lesion buccolingual width greater than two-thirds of the intercuspal distance, or requiring cusp coverage. * Partly erupted or endodontic treated teeth. * Poor oral hygiene or severe periodontitis. * Absence of neighboring or antagonist teeth. * Patients with known allergy to any component of the study materials. * Patients with unstable medical conditions. * Patients with known unavailability to attend recall visits. * Pregnant or lactating females. * Patients with heavy para-functional habits, fractured, or visibly cracked teeth.