The effect of staining solutions on the colour stability of provisional prosthodontic materials
The aim of this study was to evaluate the effects of staining solutions on the colour stability of self-cure provisional resin materials.
The specimens were prepared for each of three auto-polymerized bis-acryl resin and auto-polymerized methyl methacrylate provisional resin material. The baseline colour values were measured with a colorimeter according to the CIE L*a*b* colour scale. After the first measurement (T0), specimens were placed in staining solutions (coffee, coca-cola, burn and distilled water for control group) and the other measurements were taken after 24 h (T1), 1 week (T2) and 4 weeks (T3).
Data were analyze statistically by (a) repeated measures (ANOVA), (b) one and two way ANOVA, and (c) Tukey HSD multiple comparison tests. At the 24 h immersion period, the post hoc analysis indicated that AccessCrown-coffee revealed the highest ΔE* values (4.4). At the second immersion period (1 week), Structur2 SC-coffee had the highest ΔE* values compared with other materials (5.4).
The degrees of discoloration were increased with immersion time. The methylmethacrylate resin was more resistant to discoloration than bis-acryl resins. After immersion for 30 days, the coffee solution resulted in unacceptable discoloration for all the tested materials.