The Staining Effect of Mouthwash Containing Silver Nitrate Mouthwash on Dental Enamel: A Comparative Study

Abstract

This in-vitro study evaluated and compared the enamel staining potential of a 0.011% w/v silver nitrate solution and an ionic silver based mouthwash (SilvOral®️ supplied by ALPINIA pharmaceuticals) on extracted human premolars. Forty teeth without caries were randomly allocated to three groups: silver nitrate (n=20), ionic silver mouthwash (n=20) and distilled water control (n=20). Colorimetric measurements (ΔE, L, C, H*) were taken by Vita Easyshade®️ spectrophotometer at baseline (T1), after 24h immersion (T2) and after brushing (T3). Results found that the silver nitrate group was significantly discolored with the mean ΔE value of 10.9 in T2, with a great variation towards dark shades (C3-C4), a decrease in lightness (mean L*=-1.2). In contrast, in the mouthwash group, lighter Vita shades (A3-A4) were maintained, higher lightness values (mean L* = +8.4) were achieved and lower perceptible change of color was registered (mean ΔE = 6.3). It was found that while the stain caused by silver nitrate was largely permanent, the mouthwash group was able to partially reverse the stain (ΔE of 4.8) after brushing. Analysis of variance (ANOVA, p < 0.05) confirmed the color stability was significantly better with the mouthwash. These results indicate that the ionic silver mouthwash has lower and greater reversible enamel discoloration than silver nitrate and support it to have a safer esthetic profile for clinical application.