Physicomechanical Properties and Crown Fracture Load of 3D-Printed Resins, a Milled Resin Composite, and Lithium Disilicate Glass-Ceramic: An In Vitro Comparative Study

This in vitro study compared the physicomechanical properties and crown fracture load (CFL) of three additively manufactured (AM) resins for definitive crowns (C&B Permanent [CB], CROWNTEC [CT], and VarseoSmile Crown plus [VS]), a milled resin composite (SHOFU HC [HC]), and lithium disilicate glass-ceramic (Rosetta SM [RSM]). The degree of conversion (DC) was assessed for AM resins (n = 5 per material); flexural strength (FS), flexural modulus (FM), tensile strength (TS), compressive strength (CS), CFL, and Vickers hardness number (VHN) were assessed for all materials (n = 10 per material). Welch analysis of variance and Games–Howell comparisons were used, with Holm adjustment across seven omnibus tests (α = 0.05). All omnibus comparisons remained significant after adjustment (p < 0.001). CB and VS exhibited higher DC than CT. All measured DC values exceeded 60%, although this alone does not establish clinical adequacy. RSM exhibited the highest FS, FM, CS, and VHN, whereas CB exhibited the highest TS and CFL. Standardized specimen tests ranked the materials differently than crown fracture testing. Material selection should integrate standardized properties with restoration-level evidence. These product- and protocol-specific static results do not establish clinical indications or predict long-term survival.