*2.2. Casting-Lost Wax Technique (Cast LWT)*

Wax copings with 0.7 mm thickness and 0.2 mm marginal reinforcements were prepared to fabricate cast CoCr copings by a senior dental technician. The wax patterns were sprued and invested using phosphate-bonded investment (Fast Fire 15 investment; Whip Mix, Louisville, KY, USA) with a 16 mL/60 g liquid/powder ratio with a ring-less technique. A Whip Mix plastic ring was used with bars to provide expansion, and the molds were removed from the ring after 15 min. After removal of investment, the molds were allowed to set for 24 h. Wax pattern burn-out was performed using a furnace (PRO-GRAMIX 50, Ugin'Dentaire, Seyssinet-Pariset, France) at 900 ◦C. CoCr alloy casting was carried out using a casting machine (FORNAX 35E®, BEGO, Bremen, Germany) at 1500 ◦C temperature (Wirebond ®C; BEGO, Bremen, Germany) (composition Co 63.3% Cr 24.8% W 5.3% Mo 5.1% Si 1.0%). The copings were divested with glass beads (50 μm) at 1 bar pressure, followed by ultrasonic cleaning.

#### *2.3. Computer Aided Design-Computer Aided Manufacture (CAD-CAM)*

Master die surface was coated with a uniform layer of Cercon Eye Scan Spray (Degu-Dent GmbH, 63457 Hanau-Wolfgang, Germany) and scanning was performed using Cercon Eye scanner (DeguDent GmbH, 63457 Hanau-Wolfgang, Germany). The scan was run using Cercon Art and contours were mapped and the final image in a steriolithographic (STL) format was displayed. The copings were designed using Cercon Art software according to the prescribed dimensions. Cercon Brain (DeguDent GmbH, Hanau-Wolfgang, Germany) milling machine fabricated the copings in the prescribed design. Ceramill Sintron alloy blanks (Co-Cr-Amann Girrbach AG, Herrschaftswiese, Koblach, Austria) were secured in the milling machine and were removed on milling completion.

## *2.4. Selective Laser Melting (SLM)*

To fabricate SLM CoCr alloy copings, the STL file for coping design fabricated for the CAD-CAM technique was transferred to the Concept Laser Machine (metal laser melting system; GE Additive company, Boston, MA, USA) with standard parameters. CoCr alloy (Starbond Easy Powder 30; Scheftner GmbH, Mainz, Germany) (composition, Co

61%, Cr 27.5%, W 8.5%, Si 1.6%, C, Fe and Mn < 1%) with an alloy powder grain size of +10/−30 μm and elastic modulus of 225 GPa was used. The coping model was vertically positioned, and the support material for the printing was designed and attached within the design software. The printing process was carried out in nitrogen and argon inter atmosphere. The fiber laser beam (100 W ytterbium (Yb)) hit the powder layer in selective areas and created a melt pool resulting in the fusion of powder particles. The thickness of the powder layer was 20 μm. This process was repeated until the coping fabrication was completed.
