Effect of Staining Solutions on Color Stability, Gloss and Surface Roughness of Removable Partial Dental Prosthetic Polymers

Purpose To assess the effect of commonly used solutions on color stability, gloss, and surface roughness of removable partial dental prostheses polymers. Materials and methods Discs (n = 112) were made of a poly(etheretherketone) (PEEK) polymer, a polyamide, an acetal resin and a heat-cured poly(methylmethacrylate) PMMA acrylic resin polished according to manufacturers' instructions. Seven specimens of each material were immersed in coffee, red wine, coca cola and distilled water for 30 days at 37(omicron)C. Changes of color (Delta Epsilon*) and color coordinates L*alpha*b* after immersion were calculated with a colorimeter. Changes in the values of gloss and surface roughness parameters (Sa, Sz, Str, Sdr, Sci, Svi) were also measured. Two-way ANOVA and pairwise comparisons were used to evaluate the effect of material and staining solution on parameter value alterations (alpha = 0.05). Results The two-way ANOVA revealed that the interaction between material and staining solution significantly affected color changes after immersion [F(9,96) = 44.67, p < 0.001]. PEEK presented the lowest color change (Delta Epsilon* = 3.83 +/- 2) while polyamide had the highest color change overall (Delta Epsilon* = 14.59 +/- 8.65) (p < 0.001). Coffee caused the highest color (Delta Epsilon* = 13.08 +/- 6.98) and gloss changes (Delta G = -6.36 +/- 19.2 GU) among different solutions (p < 0.001). PEEK showed the highest alteration of gloss (Delta G = -11.31 +/- 15.49 GU), with significant difference with the other three materials (p < 0.001). Insignificant interaction of material and immersing solution was found for surface roughness parameters (p > 0.05). Conclusions Among the materials tested, PEEK seemed to be the most stable material when subjected to common, everyday staining solutions. Therefore, PEEK could be a viable solution for an RPDP framework fabrication, expanding the material list of prosthetic options. Further research and clinical trials are required to confirm the above statement.