3D printing resins are liquid photopolymer materials cured layer by layer in DLP, SLA, or LCD dental 3D printers to produce highly accurate parts directly from a digital design file. In the digital workflow, they follow intraoral or lab scanning and CAD design, and are formulated for specific applications — biocompatible resins for surgical guides, splints, and orthodontic appliances; castable resins for crown and partial-framework patterns; and denture base or denture tooth resins for full removable prosthetics. Each resin is matched to a printer's light wavelength and a defined post-processing protocol (washing and post-curing) to achieve the strength, accuracy, and biocompatibility its clinical use requires.