Objective: Color and optical properties are particularly crucial to mimic natural tooth. This scoping review aimed to present an overview of the literature published on color and optical properties of 3D printing restorative polymer‐based materials. The literature search was performed in MED‐LINE/Pubmed, Scopus and Web of Science.Materials and methods: The literature search was conducted in the three databases based on the question: “Are the optical properties and color adequately reported on polymer‐based 3D printing dental restorative materials studies?” with no restriction on year of publication. Data were reported and synthesized following PRISMA‐ScR statement.Results: Nine studies fit the inclusion criteria. Five studies focused on evaluating only color stability; three articles assessed the color stability along with mechanical and morphological properties and only one study compared color parameters of 3D printed to conventional polymers. Two studies evaluated translucency parameter and no study was found evaluating scattering, absorption, and transmittance.Conclusions: Color and optical properties of 3D printed polymers that can be used in restorative dentistry are not adequately evaluated and characterized. Future studies on the influence of experimental printing conditions should include these physical properties to assist on improving esthetics.Clinical significance: This review shows the scarce literature existing on color and optical properties of 3D printing restorative polymer‐based materials. These properties and their study are of outmost importance to create materials that mimic natural tooth to allow clinicians to obtain esthetically pleasant restorations.

To evaluate the influence of thickness and printing angle on the optical properties of 3D-printed dental restorative resins. 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 (X_∞) were calculated using Kubelka-Munk's model. Data were statistically analyzed using Kruskal-Wallis¸ Mann-Whitney tests, and VAF coefficient. The spectral distribution on S, K, T%, RI,X_∞ were wavelength dependent. Although the spectral behaviors were similar for all the specimens evaluated, the values of S, K, T% andX_∞ 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 X_∞ 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 X_∞ at 0.5 and 1.0 mm for DFT, and at 0.5 mm for FT. 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. Understanding the optical behavior of the 3D-printed restorative resins is essential to optimize their clinical performance.

Objectives: This study aims to evaluate in vivo the color agreement between natural teeth and dental shade guides by means of visual and instrumental coverage error ( $$\mathrm{CE}$$CE ) index.Materials and methods: The color of the middle third of 735 incisors was visually determined by two evaluators using the Vita Classical (VC) and Vita 3D Master (V3DM) shade guides. The color match between the natural tooth and the shade tab was rated as poor (P), good (G), or optimum (O) by each observer. CIE color coordinates of the target teeth and shade tabs of VC and V3DM were instrumentally measured using a clinical spectrophotometer. Visual ( $${\mathrm{CE}}_{\mathrm{V}}$$CEV ) and instrumental ( $${\mathrm{CE}}_{\mathrm{I}}$$CEI ) coverage error indexes were computed using CIELAB and CIEDE2000 metrics for both shade guides. For $${\mathrm{CE}}_{\mathrm{V}}$$CEV calculation, only the concordant inter-observer determination on tooth shade rated as O–O or O–G was used. The results were evaluated using perceptibility (PT, $${\mathrm{\Delta E}}_{\mathrm{ab}}^{*}$$ΔEab∗ = 1.2, $${\mathrm{\Delta E}}_{00}$$ΔE00 = 0.8) and acceptability (AT, $${\mathrm{\Delta E}}_{\mathrm{ab}}^{*}$$ΔEab∗ = 2.7, $${\mathrm{\Delta E}}_{00}$$ΔE00 = 1.8) color thresholds for dentistry.Results: VC and V3DM exhibited $${\mathrm{CE}}_{\mathrm{I}}$$CEI (2.5, 3.2, and 3.2, 2.7 CIELAB units; 1.9, 2.3, and 2.8, 2.4 CIEDE2000 units, respectively, for O–O and O–G match) and $${\mathrm{CE}}_{\mathrm{V}}$$CEV (4.7, 4.8, and 4.1, 4.6 CIELAB units; 3.3, 3.4, and 3.4, 3.6 CIEDE2000 units, respectively, for O–O and O–G match) values greater than 50:50% AT for both color difference formulas. $${\mathrm{CE}}_{\mathrm{I}}$$CEI contributes more than 50% (53.2–82.4% range) to the $${\mathrm{CE}}_{\mathrm{V}}$$CEV value. This contribution depends on the shade guide used and the quality of the visual rating.Conclusions: The evaluated shade guides exhibited visual coverage errors above acceptability thresholds, largely due to the contribution of the instrumental coverage error to the visual coverage error.Clinical relevance: It necessary to further improve commercially available dental shade guides to facilitate achievement of satisfactory esthetics results in clinical practice.