The Effect of Gastric Acid and Material Type on the Surface Roughness of Additive and Subtractive Manufacturing Resins.

Purpose: To examine the effect of gastric acid on the surface roughness of additive and subtractive manufacturing resin.

Materials and methods: In this study, two subtractive-manufacturing CAD/CAM resin nanoceramics (Cerasmart 270 [CS], Lava Ultimate [LU]) and two additive-manufacturing 3D-printing permanent resins (VarseoSmile Crownplus [VSP], Crowntec [CT]) were used. CS and LU samples were turned into 10-mm-diameter cylinders with a scraper and cut into 2-mm slices on the cutting device. CT and VSP samples were produced on a 3D printer (2-mm thickness, 10-mm diameter; n = 15). All samples were exposed to a cycle of 60 seconds of gastric acid, 5 seconds of distilled water, and 30 minutes of artificial saliva, six times a day for 10 days. Surface roughness mean (Ra) and depth (Rz) were measured with a contact profilometer at baseline and after gastric acid cycling. Data were analyzed using SPSS (version 22.0), one-way ANOVA, post-hoc Tukey, and independent t tests (P < .05).

Results: Ra and Rz values of CT and VSP were significantly higher than CS and LU at baseline and after the gastric acid cycle (P < .05). After the gastric acid cycle, the Ra and Rz values of all materials increased significantly compared to baseline (P < .05), but the Ra values of all materials were at a clinically acceptable level (< 0.2 µm).

Conclusions: Although additive-manufacturing 3D-printing permanent resins offered higher roughness values, they were still at a clinically acceptable level. Therefore, they can be used as an alternative to subtractive-manufacturing CAD/CAM resin nanoceramics.