Purpose: The effect of mouth rinses on staining and roughness of interim restorations produced by additive manufacturing is unclear. This study investigated how surface treatments and mouth rinses affect staining, surface roughness, and the role of polishing on staining. Methods: 320 disc-shaped specimens were produced from four resin materials (n=80) using conventional and additive methods. Each group was divided into two groups (n=40) according to surface applications: conventional (Group C) and sealant (Group S). After measuring surface roughness, groups were divided into four subgroups (n=10) and immersed in mouth rinses: LISTERINE (LIS), chlorhexidine gluconate 0.2% (CHX), chlorhexidine gluconate 0.1% (ELU), and artificial saliva (AS). Specimens were stored for one day (T1) and seven days (T2) in these solutions. Color measurements were performed before and after storage using a spectrophotometer, and color differences were calculated via the CIELab system. Post assessment, specimens were polished, and ∆E values were remeasured. Data were statistically analyzed with 1-Way ANOVA and Bonferroni tests (α=0.05). Results: The highest surface roughness values were observed in the PMMA, and the lowest were in printed groups among the conventional and sealanted groups (P < .05). LIS had the highest ∆E values against all mouth rinses. The surface sealant applied groups showed the lowest ∆E values and surface roughness in all time points. The process of polishing reduced ∆E values in all tested groups. Conclusions: Printed resins have sufficient optical and surface properties for interim restorations. Long-term use of mouth rinses may cause discolouration but using surface sealant and polishing may reduce this discolouration.
