Comparison of the mechanical and bonding properties of vat photopolymerization resin and resin composite blocks.

PURPOSE This study compared the mechanical properties, wear behavior, and shear bond strength (SBS) of resin luting agents in additive-manufactured composite crown materials intended for definitive restorations with those of conventional computer-aided design/computer-aided manufacturing (CAD-CAM) hybrid composite resin (HCR) block materials.

METHODS Sprintray Ceramic Crown (SP) was used as the representative vat photopolymerization (VPP)-fabricated material based on additive manufacturing, whereas Shofu Block HC Hard II (HC) and Cerasmart Prime (CS) were selected as CAD-CAM HCR block materials. The mechanical properties were evaluated using three-point flexural strength and Vickers hardness tests. The wear behavior was examined via a reciprocating sliding test using an alumina ball antagonist. The SBS was measured between each material and various resin-luting agents.

RESULTS SP showed ~50-60% of the flexural strength and 30-40% of the Vickers hardness of HC and CS. Wear testing revealed that SP exhibited greater wear loss than those of CAD-CAM HCRs. The SBS values of SP with each resin cement were slightly lower than those of HC and CS under most conditions; however, all values exceeded 15 MPa, indicating a clinically acceptable bond strength.

CONCLUSIONS The VPP-fabricated definitive crown material (SP) demonstrated inferior mechanical properties and wear resistance compared to those of conventional CAD-CAM HCRs. However, the acceptable levels of bond strength were observed, highlighting the importance of careful case selection for definitive restorations.