Quantitative Study of Topical SDF Application at Various Concentrations

Abstract

Objective: Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS) was used to determine the amount of silver present on demineralised dentine after application of various concentrations of silver diammine fluoride (SDF) . The effect of different saliva solutions on this interaction was also studied.

Method:

Dentine disks (3.8 mm diameter × 1.5 mm thick) were prepared (IRB# UW11-129) and randomly assigned for storage into 2 groups: basal medium mucin (BMM) and unstimulated whole saliva (UWS). They were then chemically demineralised for 3 days. 10 µl of 10 wt%, 24 wt% or 38 wt% SDF was then applied onto the dentine surface for 3 min, and each group (2×3 groups) was replaced in its respective salivas (BMM or UWS) for 5 days. The dentine samples were then dissolved in 70% HNO3 and the amount of silver (Ag-107) was detected using ICP-MS. As a control, the concentrations of the diluted SDF solutions were tested alone. 1-way ANOVA and Tukey HSD were used to compare the group difference statistically.

Result:

For both BMM and UWS, the presence of silver increased with increasing concentrations of SDF (p < 0.05) (Table Mean (± SD) silver (mg/kg)). BMM groups were found to yield significantly higher amount of silver at 12 wt% and 38 wt% of SDF application (P<0.001).

Treatment Group

BMM (Group 1,3,5,7)

UWS (Group 2,4,6,8)

1/2.Dentine (substrate)

-4.69 ± 5.17* a

-6.89 ± 3.65* a

3/4.Dentine+10% SDF

304.42 ± 3.84 b

211.02 ± 1.10 c

5/6.Dentine+24% SDF

409.40 ± 5.19 d

416.54 ± 4.22 d

7/8. Dentine+38% SDF

1012.57 ± 4.73 e

590.75 ± 3.78 f

*contributed by the signal noise and no assumption for zero concentration in Ag-107 calibration curves.

Conclusion:

For UWS, the amount of silver was in proportion to the application of various concentrations of SDF solutions. However, for BMM, the higher amount of silver at 10% and 38% SDF indicates an interaction with excessive salivary proteins.