Purpose: evaluation of biological and esthetical success of ceramic onlay restorations using shoulder finish line preparation versus butt joint with bevel finish line. Methodology: 30 participant’s were enrolled with total 38 teeth. Ceramic onlay restorations were fabricated for upper premolars. Using two different preparation designs, teeth were randomized into two groups: group (S) for onlay preparation design with shoulder finish line and group (B) for onlay preparation design with butt joint with bevel