Clinical trials

The goal of this clinical trial is to learn whether onlay restorations produced by additive manufacturing \[three-dimensional (3D) printing\] and subtractive manufacturing \[Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM) milling\] perform equally well in vital posterior teeth. The main questions it aims to answer are: * Do 3D printed onlay restorations show similar marginal adaptation and clinical performance compared to CAD/CAM milled onlays? * Are there any differences in biological compatibility, surface properties, or postoperative sensitivity between the two techniques over time? Researchers will compare onlay restorations fabricated with 3D printing and CAD/CAM milling using a split-mouth study design. Participants will: * Receive one onlay restoration produced by 3D printing and another produced by CAD/CAM milling, placed on opposite sides of the mouth * Have checkups at baseline (1st week), 6 months, 12 months, and 18 months after treatment * Be evaluated using the Fédération Dentaire Internationale (FDI) criteria for marginal adaptation, surface quality, anatomical form, and biological compatibility