3D-Printed Versus Conventional Dental Provisional Resins: A Comparative Study

Background and Objectives: This study aimed to evaluate and compare the effects of immersion and brushing on resins used for temporary crowns, including two 3D-printed resins (Nanolab and PrintaX) and one self-curing resin (Duralay), with different surface finishing protocols. Materials and Methods: Printed specimens were designed using specialized software, followed by slicing and printing. Self-curing resin samples were fabricated using silicone matrices, with the printed specimens serving as references. Square samples (7.0 × 7.0 × 2.0 mm, n = 90) were divided into three groups based on surface finishing: extrinsic pigment with glaze, glaze only, and polish only. The samples were immersed in 15 mL of cola soft drink, energy drink, or distilled water for six days at 37 °C in a dark environment before undergoing a brushing test (180 cycles/minute, 65,700 cycles, 2 N, 37 °C). Color alterations, surface roughness, and Knoop microhardness were then analyzed. Results: Statistical analyses revealed that all factors significantly influenced the tested properties (p < 0.05). Nanolab exhibited the most pronounced color alterations, with ∆E00 values reaching up to 22.21 ± 3.13 in specific conditions (e.g., Glaze, Cola soft drink). It also presented increased surface roughness, particularly when compared to PrintaX. Conversely, Duralay consistently displayed the highest Knoop microhardness changes (e.g., ranging from −1.84 ± 0.36 to 0.47 ± 0.45 in different conditions) across most experimental groups. Polishing consistently provided better outcomes in terms of color stability, surface roughness, and microhardness compared to extrinsic pigment + glaze or glaze-only treatments. The first immersion generally led to the greatest color change. Conclusions: The acidic challenge promoted significant changes in the optical and surface properties of the evaluated resins, increasing ∆E00 and roughness and reducing microhardness to different extents depending on the material. Clinically, these findings highlight the relevance of material selection and limiting exposure to acidic beverages during provisional use.