Supplementary Material for: Incorporation of Green Capping Agents to Reduce Silver-mediated Dentine Staining

Silver diammine fluoride (SDF) is known as a non-invasive, cost-effective, safe and simple method of dental caries treatment. However, staining and discoloration seem inseparable with SDF and continue as a cosmetic concern. Research is ongoing to overcome these issues for example by using glutathione or potassium iodide among others. Therefore, the study aimed to investigate the effects of incorporating different concentrations of capping agents on SDF chemistry and SDF-mediated tooth staining at different time points. Tannic acid (TA), gallic acid (GA), carboxymethyl chitosan (CM), and glutathione (G) at different concentrations (5, 10, and 15% w/v) were incorporated in 30% SDF. FTIR and UV-Vis spectroscopy of the prepared solutions was performed to evaluate chemical changes. Time-dependent color changes (ΔE) in bovine dentine specimens (6×6×1 ± 0.25 mm3) were measured spectrophotometrically at: application/washup, 1 and 3hrs, after 1,2,4,7, and 14 days. Results showed suppression of FTIR peaks at 3358cm-1 and 1215cm-1 in capping agent modified SDF indicative of a successful capping effect of the silver ions, which was corroborated by UV-Vis blueshift of ~∆32nm. The capping effect on SDF increased proportionally with the concentration of TA, GA, CM and G used. A more pronounced tooth staining reduction however, shown more in TA- and G- rather than in GA- and CM-modified SDF. At day-14, SDF showed the highest mean ΔE(50.14±2.14), while 15% TA showed the lowest ΔE(30.14±0.81). In conclusion, capping agent incorporation significantly reduced SDF-mediated tooth staining. This reduction in staining is more dependent on the respective capping agent functional groups than concentrations per se. The potential of capping agents to minimize tooth staining of SDF was TA>G>CM>GA.