A pilot study on professional cleansing protocols for PMMA resins produced by CAD/CAM and 3D printing technologies: Effects on surface roughness and color stability

Objectives: This in vitro pilot study evaluated the effects of two professional cleansing protocols on surface roughness and color stability of various resins for complete dentures. Methods: 50 resin specimens were prepared and divided into five groups (n = 10): Probase Hot (PH, Ivoclar AG), IvoBase CAD (IBC, Ivoclar AG), Ivotion Dent (ID, Ivoclar AG), Dima Print Denture Base (DPDB, Kulzer), and Dima Print Denture Teeth (DPDT, Kulzer). After a 7-day immersion in coffee solution, two cleansing protocols were applied: a chemical one using an alkaline solution, and a combined mechanical+chemical one involving an acid-based cleaning agent with a rotating needle device followed by the same chemical protocol. Surface roughness was measured before and after cleaning using a structured light profilometer (Confovis) connected to a microscope (Eclipse LV150N, Nikon). Color stability was assessed with a colorimeter (Easy_Color, SmartVision). One specimen per group underwent SEM analysis at baseline and after both protocols. The data analysis was performed by using Kruskal-Wallis test and post-hoc Dunn test for comparison. Results: Surface roughness was not significantly affected by either protocol (p>0.05). All ΔE values were below the perceptibility threshold (ΔE<1.2), except for ID after both the chemical (ΔE = 2.28) and the mechanical+chemical protocol (ΔE = 2.39) and DPDB after both the chemical (ΔE = 2.06) and the mechanical+chemical protocol (ΔE = 2.33). Conclusions: Surface roughness and color stability of PMMA resins were not affected by the tested cleansing protocols, so they could be used by clinician during the periodically control visit. Clinical Significance: The proposed cleansing protocols help preserve the long-term aesthetic and functional integrity of dentures, enhancing patient satisfaction and oral health.