Acidity, fluoride and silver ion concentrations in silver diamine fluoride solutions: a pilot study

Evaluation of the cytotoxicity of new formulations of cariostatic agents containing nano silver fluoride: an in vitro study

The objective of the study was to assess the indirect cytotoxicity of 600 ppm and 1500 ppm nano silver fluoride (NSF) compared to other commercial cariostatic agents. 56 dentin discs with 0.4 mm in thickness were obtained from intact human molars and adapted to artificial pulp chambers (APCs). The discs were divided into seven groups according to treatment (n = 8): no treatment (positive control-PC), 29% hydrogen peroxide (negative control-NC), 30% Cariestop (CS30), 38% Riva Star (RS38), 38% Advantage Arrest (AA38), 600 ppm NSF (NSF600), and 1500 ppm NSF (NSF1500). The cariostatic agents were applied on the occlusal surface of the dentin discs (facing upward), and the pulp surface (facing downward) remained in contact with the culture medium. Immediately after the treatments, the extracts (DMEM + cariostatic agent components diffused through the discs) were collected and applied to MDPC-23 cells, which were assessed for viability (CV-alamarBlue, live/dead), adhesion/spreading (F-actin), alkaline phosphatase (ALP) activity, and mineralization nodule (MN) formation. The data were statistically analyzed by ANOVA/Games-Howell (p = 0.05). CV and ALP activity in CS30, RS38, AA38, and NSF600 were similar to PC (p > 0.05). MN formation significantly decreased only in NC, CS30, RS38, and AA38 compared to PC (p < 0.001). Only NSF600 and NSF1500 did not differ from PC (p > 0.05) with mineralization nodules, and this specific cell activity significantly decreased in all other groups (p < 0.05). NSF solutions (600 ppm and 1500 ppm) did not cause transdentinal toxicity on MDPC-23 cells.

Evaluation of Fluoride and Silver Ion Concentrations in e-Silver Diamine Fluoride and Advantage Arrest: An Ion Chromatography and Atomic Absorption Spectrometer Study

Aims and background

Dentin hypersensitivity (DH) is characterized by sharp shooting pain due to exposed dentin, and the most common method for treating this pain is the occlusion of the dentinal tubules with the help of desensitizing agents. E-silver diamine fluoride (e-SDF) (Kids-e-Dental, Mumbai, India) is a commercially available 38% SDF solution in the Indian market. Despite the fact that its application for caries prevention has been proven, the fluoride (Fl) and silver (Ag) ion concentrations of e-SDF for use in treating DH have yet to be standardized. The aim of this study is to determine and compare the Fl and Ag ion concentrations released from two commercially available 38% silver diamine fluoride (SDF) solutions.

Materials and methods

The two most common commercially available 38% SDF solution brands, namely Advantage Arrest and e-SDF were used. Two drops of each of these solutions were taken in three beakers and diluted with distilled water. The Fl ion concentration was evaluated using a calibrated ion-specific electrode. The free Ag ion concentration was assessed using an atomic absorption spectrometry (AAS).

Results

Release of Ag ions shows that on days 1, 2, 5, 6, and 7, concentration (mg/L) was higher in the Advantage Arrest group but is statistically nonsignificant. On days 3 and 4, it is higher in an e-SDF group with a t-value of 1.085 and 0.243 and is statistically nonsignificant. Release of Fl ion showed that in comparison to the baseline, it was more with Advantage Arrest on days 2, 4, and 7 with a t-value of -3.766, -0.999, and 0.347 and on day 2 was statistically significant. On days 3, 5, and 6 Fl ion release from baseline was more with e-SDF in comparison with Advantage Arrest but statistically insignificant.

Conclusion

The AAS analysis as well as the ion chromatography showed that the Ag and Fl ion release respectively on days 1-7 from e-SDF was similar to the one seen in the case of Advantage Arrest.

Clinical significance

This helps dentists choose among different brands of the same commercially available 38% SDF solutions depending on the cost and availability of the product.

How to cite this article

Kamath P, Kamath P, P AN, et al. Evaluation of Fluoride and Silver Ion Concentrations in e-Silver Diamine Fluoride and Advantage Arrest: An Ion Chromatography and Atomic Absorption Spectrometer Study. Int J Clin Pediatr Dent 2024;17(10):1141-1145.

Explorations of the chemical constitution and aqueous solution status of caries-arresting silver(I)-diammine fluoride and silver(I)-fluoride products using high-resolution 19F NMR analysis. Spectroscopic and SEM investigations of their interactions with human saliva: evidence for the in vivo salivary-catalysed autoconstruction of Ag/AgCl-based nanoparticles (IV-SCAN)-part I

Introduction

Silver(I)-diammine fluoride (SDF) and silver(I)-fluoride (SF) complexes have been successfully employed for the arrest of dental caries for many years. However, to date there are very few studies available reporting on the molecular structural compositional and solution status of these agents [typically applied as highly-concentrated 38% (w/v) solutions]. Here, we explored the solution status and chemical constitution of commercially-available SDF and SF products, and secondly investigated the multicomponent interplay of these products with biomolecules present in intact human whole-mouth salivary supernatants (WMSSs) in vitro.

Methods

High-resolution 19F NMR analysis was employed to explore SDF and SF product solutions, and to determine WMSS fluoride (F-) concentrations, whereas ammonia (NH3) release form SDF was tracked by 1H NMR spectroscopy. SEM and thin-film FTIR-ATR analyses were employed to explore the atomic and molecular compositions of sequentially-generated AgCl deposits and chromophoric Ag/AgCl nanoparticles (CSNPs); the time-dependent generation of the latter was followed spectrophotometrically.

Results

19F NMR spectra of aqueous SF solutions contained a very broad F- signal (Δv1/2 70 Hz), demonstrating that much of its solvated F- content was rapidly exchanging with Ag(I) on the NMR timescale, but those of SDF had a much sharper resonance, similar to that of "free" F- (4 Hz). Moreover, further NMR results revealed that a popular SDF product contained high molar excesses of both F- and NH3. Treatment of WMSSs with SDF and SF generated an off-white precipitate, which slowly developed into CSNPs at 23°C; SEM demonstrated high contents of both silver and chloride in this material (ca.1:1 atomic content ratio). FTIR-ATR analysis found that the CSNPs formed contained a range of salivary biomolecules, which appear to encapsulate the Ag/AgCl core (significant thiocyanate contents were also found). In conclusion, NMR results acquired demonstrated that SF, but not SDF, product solutions feature rapidly-exchanging F - between its "free" and Ag(I)-bound forms, and that SDF contains large excesses of both F- and its NH3 ligands. Characterised AgCl deposits and CSNPs were sequentially produced from the interactions of these complexes with WMSS biomolecules.

Discussion

In view of their well-known microbicidal and cariostatic properties, the observed autobioconstruction of CSNPs involving salivary catalysis is of much therapeutic significance.

Stability of Silver and Fluoride Contents in Silver Diamine Fluoride Solutions

OBJECTIVE

This study aims to determine the stability, alkalinity, and fluoride and silver ion concentrations of 5 commercially available 38% silver diamine fluoride (SDF) solutions-namely Advantage Arrest, e-SDF, Riva Star, Saforide, and Topamine-in 180 days.

METHODS

Alkalinity was determined using a pH electrode. The fluoride and silver ion concentrations were obtained using a calibrated ion-selective electrode and optical emission spectrometer, respectively. Six bottles of each product were examined on days 0 (freshly opened), 30, 60, 90, and 180. The time taken for each freshly opened product to form a black silver precipitate under room light (500 lx) and 25 °C was also recorded.

RESULTS

For 180 days, Advantage Arrest, e-SDF, Riva Star, Saforide, and Topamine had the pH range of 9.8-9.8, 10.5-10.6, 13.0-13.1, 9.8-9.8, and 9.3-9.4; fluoride ion concentration range (nearest 1000 ppm) of 40.9%-42.4%, 46.7%-50.9%, 37.0%-39.0%, 37.0%-45.7%, and 47.7%-53.4%; silver ion concentration range (nearest 1000 ppm) of 283.4-307.0, 307.3-315.4, 418.6-435.7, 266.3-281.0, and 416.2-456.1 ppm; and precipitation time (nearest hour) of 17, 12, 6, 7, and 7 hours, respectively. The percentage change of fluoride and silver could be more than 5% after 60 days.

CONCLUSIONS

The alkalinity of the 5 SDF solutions remained stable after 180 days. In addition, their fluoride and silver concentrations decreased substantially after 60 days. The freshly opened SDF solutions did not precipitate within 5 hours under ambient room conditions. The alkalinity and fluoride and silver concentrations of the 38% SDF solutions could be less stable after 60 days; thereafter, the fluoride and silver concentrations decreased. Thus, the SDF solution should be used within 60 days after opening.

Silver diamine fluoride therapy for dental care

Silver diamine fluoride (SDF) was developed in Japan in the 1960s. It is used to control early childhood caries, arrest root caries, prevent fissure caries and secondary caries, desensitise hypersensitive teeth, remineralise hypomineralised teeth, prevent dental erosion, detect carious tissue during excavation and manage infected root canals. SDF is commonly available as a 38% solution containing 255,000 ppm silver and 44,800 ppm fluoride ions. Silver is an antimicrobial and inhibits cariogenic biofilm. Fluoride promotes remineralisation and inhibits the demineralisation of teeth. SDF also inactivates proteolytic peptidases and inhibits dentine collagen degradation. It arrests caries without affecting dental pulp or causing dental fluorosis. Indirect pulp capping with SDF causes no or mild inflammatory pulpal response. However, direct application of SDF to dental pulp causes pulp necrosis. Furthermore, SDF stains carious lesions black. Patients must be well informed before SDF treatment. SDF therapy is simple, painless, non-invasive, inexpensive, and requires a simple armamentarium and minimal support. Both clinicians and patients generally accept it well. In 2021, the World Health Organization included SDF as an essential medicine that is effective and safe for patients. Moreover, it can be used for caries control during the COVID-19 pandemic because it is non-aerosol-generating and has a low risk of cross-infection.

Fluoride and silver ion concentrations and pH in silver diamine fluoride solutions from Argentina

The aim of this study was to measure the fluoride (F) and silver (Ag) ion concentration and the pH, over time, of 2 solutions of 38% silver diamine fluoride (SDF) produced in Argentina. The brand Fluorsilver® was established as Group 1 (G1) (Densell), and the brand FAgamin® (Tedequim) as Group 2 (G2), each with two different lots. The following were determined at time 0 (t0) and 30 days after opening (t30): a) fluoride concentration (w/v) by visible spectrophotometry b) Ag content (w/v) by atomic absorption spectrophotometry c) pH. Results: The data in the freshly opened bottles were for G1 lot1/lot2: a) 0.96/1, b) 8.3/7.8, c).11.5/11.3; G2 lot1/lot2: a) 11.5/9.9, b) 39/39, c) 7/6,9; and after 30 days, G1 lot1/lot2: a) 0.85/0.81, b) 7.2/8.2, c) 11.3/11.6; G2 lot1/lot2: a) 9.35/8.43, b) 38/38, c) 7.6/7.6. Conclusion In relation to the expected values (5.0-5.9% fluoride and 24.4-28.8% silver), the average concentration of fluoride and silver ions was lower for G1, but higher for G2. The pH was alkaline for G1 and neutral for G2. Over the 30 days, the content of fluoride and silver tended to decrease.

Fluoride Delivered via a Topical Application of 38% SDF and 5% NaF

OBJECTIVES

The objectives of this study were to compare the amount of fluoride delivered via a topical application of 38% silver diamine fluoride (SDF) solution and 5% sodium fluoride (NaF) varnish as well as to determine the amount of 38% SDF solution delivered using various micro-applicators.

METHODS

The weights of 38% SDF (Saforide) and 5% NaF (Duraphat) applied to the occlusal surface of an extracted human upper first premolar with a regular-size (2.50-mm tip diameter) micro-applicator were measured using an electronic-analytical balance. Afterwards, the weight of 38% SDF applied to a premolar using the micro-applicators of 5 common brands (Premium Plus, 3M, Dentsply, Elevate Oral Care, and SDI) were studied. The tip diameter of each micro-applicator was measured under a microscope. The weights of the delivered fluoride and silver were also calculated.

RESULTS

The mean weights of the fluoride delivered via the SDF solution and NaF varnish were 0.25 ± 0.07 mg and 0.49 ± 0.08 mg, respectively (P < .001). In addition, the tip diameters of the micro-applicators ranged from 1.89 ± 0.03 mm to 2.76 ± 0.02 mm. The mean weights of the fluoride delivered per application of 38% SDF using different applicators ranged from 0.13 ± 0.06 mg to 0.30 ± 0.09 mg, whereas the mean weights of the silver ranged from 0.76 ± 0.32 mg to 1.68 ± 0.50 mg. The weights of the delivered 38% SDF solution varied with the brand and with the tip diameters of the dental micro-applicators (P < .001).

CONCLUSIONS

The fluoride of the 38% SDF solution delivered topically was significantly less than that of 5% NaF varnish. Moreover, the amount of SDF solution delivered depends on the brand and size of the micro-applicators.

The Cytocompatibility of Silver Diamine Fluoride on Mesenchymal Stromal Cells from Human Exfoliated Deciduous Teeth: An In Vitro Study

Silver diamine fluoride (SDF) has been used for many years for the treatment of caries, and minimally invasive dentistry concepts have made it popular again. The fact that its application does not require the administration of anesthesia makes its use in children more desirable. The aim of this study was to determine the cytotoxicity of two new commercial SDF products: Riva Star (SDI Dental Limited) and e-SDF (Kids-e-Dental) on mesenchymal stromal cells from human exfoliated deciduous teeth (SHEDs). SHEDs were exposed to SDF products at different concentrations (0.1%, 0.01% and 0.005%). Then different assays were performed to evaluate their cytocompatibility on SHEDs: IC50, MTT, cell migration (wound healing), cell cytoskeleton staining, cell apoptosis, generation of intracellular reactive oxygen species (ROS), and ion chromatography. Statistical analyses were performed using one-way ANOVA and Tukey’s post hoc test (p < 0.05). Riva Star Step 2 showed the same cell metabolic activity when compared to the control condition at any time and concentration. Meanwhile, e-SDF displayed high cytotoxicity at any time and any concentration (*** p < 0.001), whereas Riva Star Step 1 displayed high cytotoxicity at any time at 0.1% and 0.01% (*** p < 0.001). Only e-SDF showed a statistically significant decreased cell migration rate (*** p < 0.001) at all times and in all concentrations. At 0.1%, e-SDF and Riva Star Step 1 only showed 4.37% and 4.47% of viable cells, respectively. These results suggest that Riva Star has better in vitro cytocompatibility on SHEDs than does e-SDF. Riva Star Step 1 was found to be as cytotoxic as e-SDF, but it had better biological properties when mixed with Riva Star Step 2. Our findings suggest that Riva Star is more suitable when used in deciduous teeth due to its lower cytotoxicity compared to e-SDF.