Given the growth-related challenges in pediatric and adolescent patients and the increasing adoption of digital workflows, durable yet adaptable materials are needed for provisional restorations. This study evaluated the mechanical performance of two 3D-printed resins, Graphy TC-80DP (GP) and NextDent C&B MFH (ND), and a milled nano-hybrid resin, Mazic Duro (MD). A multidimensional assessment was conducted, including fracture resistance, flexural strength, flexural modulus, viscoelasticity, and polymerization behavior. ND showed the highest fracture resistance, MD exhibited superior flexural strength and flexural modulus, and GP demonstrated faster polymerization and greater thermal stability. These findings suggest that both 3D-printed and milled resins are clinically viable for pediatric provisional restorations, with material selection depending on occlusal load, patient age, and functional demands.