Effect of polishing and denture cleansers on the surface roughness of new-generation denture base materials and their color change after cleansing

Purpose: To evaluate the effect of polishing and denture cleansers on the surface roughness (R a ) of new-generation denture base materials that are additively, subtractively, and conventionally fabricated, while also assessing their color change after cleansing. Material and methods: One hundred and fifty disk-shaped specimens (Ø10 × 2 mm) were prepared from five denture base materials (one subtractively manufactured nanographene-reinforced prepolymerized polymethylmethacrylate (PMMA) (SM-GC), one subtractively manufactured prepolymerized PMMA (SM-PM), two additively manufactured denture base resins (AM-DT and AM-ND), and one heat-polymerized PMMA (CV) (n = 30). The R a of the specimens was measured before and after conventional laboratory polishing, while color coordinates were measured after polishing. Specimens were then divided into three subgroups based on the denture cleanser: distilled water, 1% sodium hypochlorite (NaOCl), and effervescent tablet (n = 10). The R a and color coordinates were remeasured after nine cleansing cycles over a period of 20 days. The CIEDE2000 formula was used to calculate the color differences (ΔE 00 ). Two-way analysis of variance (ANOVA) was used to analyze the R a values before (n = 30) and after (n = 10) cleansing, while repeated measures ANOVA was used to analyze the R a of material-time point pairs within each denture cleanser (n = 10). ΔE 00 data after denture cleansing was also analyzed by using two-way ANOVA (n = 10) (α = 0.05). Results: Before polishing, R a varied significantly among the materials. SM-GC and SM-PM had the lowest and AM-ND the highest R a values (P < 0.001). Polishing significantly reduced R a of all materials (P < 0.001), and after polishing, R a differences among materials were nonsignificant (P ≥ 0.072). Regardless of the denture cleanser, the R a of AM-DT, AM-ND, and CV was the highest before polishing when different time points were considered (P < 0.001). After cleansing, AM-ND had the highest R a of all the materials, regardless of the ...