Color Stability of PMMA Resins for Complete Dentures Produced with CAD/CAM and 3D-Printing Technologies: An In Vitro Study.

Purpose: To evaluate the effect of a staining solution on the color stability of resins for complete dentures produced with conventional and digital technologies.

Materials and methods: A total of 60 resin specimens were prepared and divided into six groups of 10 specimens each: Probase Hot (PH; Ivoclar), IvoBase CAD (IBC; Ivoclar), Ivotion Dent (ID; Ivoclar), Ivotion Dent Multi (IDM; Ivoclar), Dima Print Denture Base (DPDB; Kulzer), and Dima Print Denture Teeth (DPDT; Kulzer). One surface of each specimen was polished following the manufacturer's instructions. The CIELab color differences were evaluated before and after 28 days of immersion in a coffee solution and measured as ∆E using two dental spectrophotometers. One specimen for each group was selected for scanning electron microscopy (SEM) analysis at baseline and at 28 days.

Results: Data analysis was performed with Kruskal-Wallis test and post-hoc Dunn test for comparison. Regarding specimens analyzed with VITA Easyshade, IDM white zone (polished and unpolished) scored higher (∆E = 0.87 and ∆E = 1.15, respectively). All milled samples (IBC, ID, IDM pink zone), scored significantly higher compared to PH and DPDT. Regarding SpectroShade, IDM pink zone performed better for both polished and unpolished specimens (∆E = 1.57 and ∆E = 2.07, respectively). ID demonstrated a statistically higher color stability compared to PH and DPDT. Regarding SEM analysis, any difference in surface morphology was observed between baseline and 28-day immersion analyses.

Conclusions: Color stability was significantly higher in resin specimens obtained with digital technologies compared to conventional resin specimens afterimmersion in a staining solution.