A narrative review on the fit and fracture resistance of milled and 3D-printed interim restorations in dental and implant applications

This narrative review explores the comparative performance of milled and 3D-printed interim restorations in both tooth-supported and implant-supported dental and implant applications, with a focus on two critical clinical factors: fit and fracture resistance. Interim restorations serve vital functions during the healing and integration phases by preserving occlusion, aesthetics, and soft tissue health. The digital revolution in dentistry has introduced subtractive milling and additive 3D printing as primary fabrication techniques for temporization. Milled restorations typically offer higher precision and better marginal and internal adaptation due to the controlled machining of homogenous materials. In contrast, 3D-printed restorations provide enhanced design flexibility and faster fabrication, though their accuracy is influenced by print orientation, resolution, and post-processing steps. Regarding fracture resistance, milled interim restorations demonstrate superior strength due to their structural uniformity and the use of high-density materials like PMMA and zirconia. Conversely, 3D-printed restorations, while improving with advances in resin formulations and curing protocols, may exhibit lower fracture thresholds due to layer-by-layer construction and material limitations. Implant-supported restorations further complicate these outcomes due to the complex geometries and passive fit requirements. Milled solutions currently remain the standard for high-load and precision-demanding cases, whereas 3D printing is favored for cases requiring rapid customization and lower-cost alternatives. This review highlights the need for careful technique selection based on clinical requirements, material properties, and patient needs. Future innovations in material science, printing resolution, and hybrid digital workflows are expected to further bridge the gap between the two techniques.