Comparison of surface roughness and color stainability of 3-dimensionally printed interim prosthodontic material with conventionally fabricated and CAD-CAM milled materials

Statement of problem: Studies on the surface roughness and color stainability of interim prostheses produced with 3-dimensional-printing technology are lacking.

Purpose: The purpose of this in vitro study was to investigate the effect of different surface treatments on the surface roughness and stainability of 3-dimensionally printed, computer-aided design and computer-aided manufacturing (CAD-CAM) milled and conventional interim materials.

Material and methods: A total of 320 specimens were fabricated from autopolymerizing polymethyl methacrylate, bis-acryl composite resin, CAD-CAM polymethyl methacrylate resin (milled), and 3-dimensionally printed composite resin (printed) (n=80). A group of each material was divided into 2 groups (n=40) as per the applied surface treatment procedure: conventional polishing (C) or coated with a surface sealant (B). Surface roughness values were measured with a profilometer. Each group of specimens was then divided into 4 subgroups (n=10) and stored for 1 day, 7 days, and 30 days at 37 °C in different solutions: distilled water, cola, coffee, and red wine. Color parameters were measured with a spectrophotometer before and after each storage period, and color differences (CIEDE2000 [ΔE₀₀]) were calculated. Data were statistically analyzed with the Shapiro-Wilk test, Kruskal-Wallis test, and Mann-Whitney U test followed by the Friedman test (α=.05).

Results: The highest surface roughness values were determined for the polymethyl methacrylate -C, and the lowest were observed in the printed-B. After 30 days, the highest mean ΔE₀₀ values were observed in polymethyl methacrylate-C for all staining solutions (P=.001). The highest ΔE₀₀ for all materials was observed in the red wine group. Color change increased significantly with storage duration (P=.001).

Conclusions: All tested materials had a surface roughness higher than the plaque accumulation threshold (0.2 μm). The surface roughness values of coated materials were significantly lower than those of their conventionally polished groups, except for the printed groups. The application of a surface sealant agent significantly decreased the staining of the materials.