Optical behavior of 3D-printed dental restorative resins: Influence of thickness and printing angle Espinar Pulgar, Cristina Della Bona, Alvaro Tejada Casado, María de la Nativida Pulgar Encinas, Rosa María Pérez Gómez, María Del Mar 3D-printed dental resin Thickness Printing orientation Kubelka-Munk Theory Scattering Absorption Transmission Light reflectivity The authors also acknowledge Detax GmbH, Formlabs Inc. and GC Corporation for providing the polymer-based 3D printing restorative resins used in this study. Objectives To evaluate the influence of thickness and printing angle on the optical properties of 3D-printed dental restorative resins. Methods Four 3D printing resin systems were evaluated: DFT-Detax Freeprint Temp; FP- Formlabs Permanent Crown; FP- Formlabs Temporary CB; and GCT- GC Temporary-. Samples from each material were printed at 0° and 90°, and polished up to 0.5, 1.0, 1.5 and 2.0 mm thickness. Scattering (S), absorption (K) and albedo (a) coefficients, transmittance (T%), light reflectivity (RI) and infinite optical thickness ( ) were calculated using Kubelka-Munk’s model. Data were statistically analyzed using Kruskal–Wallis¸ Mann-Whitney tests, and VAF coefficient. Results The spectral distribution on S, K, T%, RI, were wavelength dependent. Although the spectral behaviors were similar for all the specimens evaluated, the values of S, K, T% and presented significant differences between specimen thicknesses for all the materials used and for both printing orientations. Values for S and K increased, and T% and decreased. Significant differences between 0° and 90° were found for RI values at 0.5 and 1.0 mm thick samples, for S and K at 2.0 mm, for at 0.5 and 1.0 mm for DFT, and at 0.5 mm for FT. Conclusions Optical properties of 3D-printed restorative resins vary between thicknesses, and could be affected by the building orientation. Therefore, these factors should be considered in order to improve the biomimetic potential of 3D-printed dental restorative resins. Clinical significance Understanding the optical behavior of the 3D-printed restorative resins is essential to optimize their clinical performance. 2023-10-30T10:58:36Z 2023-10-30T10:58:36Z 2023-08-17 journal article C. Espinar et al. Optical behavior of 3D-printed dental restorative resins: Influence of thickness and printing angle. Dental Materials 39 (2023) 894–902 [https://doi.org/10.1016/j.dental.2023.08.003] https://hdl.handle.net/10481/85330 10.1016/j.dental.2023.08.003 eng http://creativecommons.org/licenses/by-nc-nd/4.0/ open access Attribution-NonCommercial-NoDerivatives 4.0 Internacional Elsevier