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

Purpose: The aim of this study is 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 nanoceramic (CerasmartTM270 (CS), LavaTM Ultimate (LU)) and two additive manufacturing 3D printing permanent resin (VarseoSmile Crownplus (VSP), Crowntec (CT)) was 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 (2mm thickness-10mm 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, 6 times a day for 10 days. Surface roughness mean (Ra) and depth (Rz) was measured with a contact profilometer at baseline and after gastric acid cycling. Data were analyzed using SPSS (22.0), One way ANOVA, post-hoc Tukey's and Independent-t test (p <.05).

Results: Ra-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-Rz values of all materials increased significantly compared to the baseline (p <.05) but the Ra values of all materials were at a clinically acceptable level (<0.2µm).

Conclusion: Although additive manufacturing 3D printing permanent resins offered higher roughness values, they weren't at a clinically unacceptable level. Therefore, they can be an alternative to subtractive manufacturing CAD-CAM resin nanoceramics.