Effect of airborne-particle abrasion protocol on surface, mechanical, and adhesive properties of 3D-printed resin-based and milled materials for definitive dental restorations

To evaluate the effect of airborne-particle abrasion (APA) protocol on the microtopography, surface roughness (Sa), flexural strength (FS), and tensile bond strength (TBS) of 3D-printed resin-based composite (3D-RBC) and milled hybrid materials. Two 3D-RBC (Ceramic Crown; SprintRay, LA, USA and VarseoSmile Crown plus; BEGO, Bremen, Germany) and a milled material (Shofu Disc HC; Shofu, Tokyo, Japan) were subjected to APA using either Al 2 O 3 (50 μm) or glass beads (50 μm), at 1.5 or 3 bars. Surface morphology was characterized using a scanning electron microscope. Surface microtopography and Sa 3D laser scanning microscope. Three-point bending FS was evaluated using a universal testing machine. TBS and failure modes were evaluated after 10k thermocycles. APA protocol significantly influenced the surface morphology and microtopography of 3D-RBCs and milled materials. APA using Al 2 O 3 resulted in significantly higher mean Sa for the three materials tested compared with glass beads. APA with Al 2 O 3 at 3 bars significantly reduced the FS of the three materials tested. Ceramic Crown showed superior FS compared to VarseoSmile Crown plus and Shofu Disc HC. At an air pressure of 1.5 bars, APA with Al 2 O 3 resulted in significantly higher TBS compared to glass beads, with no statistically significant difference between Al 2 O 3 at 1.5 bars and glass beads at 3 bars. APA with either Al 2 O 3 at 1.5 bars or glass beads at 3 bars improved adhesion to 3D-RBCs and milled hybrid materials. Using glass beads at 3 bars in APA could increase surface roughness without compromising flexural strength.