Effect of silver diamine fluoride on vital dental pulp: A systematic review

The performance of silver diamine fluoride on bond strength and ultramorphology of universal adhesive to artificial carious dentin under thermocycling conditions

OBJECTIVES

To investigate the effect of silver diamine fluoride (SDF) on the microtensile bond strength (µTBS) and resin-dentin interface of universal adhesive (etch-and-rinse mode) under thermocycling.

MATERIALS AND METHODS

Artificial caries lesions were induced on human dentin discs using a bacterial model and divided into four groups: C (no treatment), CT (no treatment, thermocycling), CS (SDF), and CST (SDF, thermocycling). The treated-dentin surface was bonded with universal adhesive (etch-and-rinse mode) and stored for 24 h or subjected to 10,000 thermocycles. µTBS was performed with 1 mm/min crosshead speed with a 50 N load cell (n = 16/group). The resin-dentin interface was examined using confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDX) (n = 3/group). Statistical analyses included two-way ANOVA with Bonferroni post-hoc tests for µTBS and Fisher's Exact Test with Bonferroni correction for failure mode distribution.

RESULTS

The highest bond strength was observed in C (24.28 ± 2.27 MPa) followed by CST (18.26 ± 5.63 MPa). Significantly lower µTBS was detected in CS (14.20 ± 3.32 MPa) and CT (12.72 ± 2.12 MPa). CT exhibited a distinct failure mode from the other groups (p < 0.05). CLSM revealed less uniform resin tags in CS and CST. EDX demonstrated silver deposition at 50 μm beneath the adhesive layer in CS and at 120 μm with lower intensity in CST.

CONCLUSIONS

SDF enhances bonding durability, as evidenced by increased µTBS and modified resin-dentin interface.

CLINICAL RELEVANCE

SDF may enhance the durability of bonding with universal adhesive in etch-and-rinse mode.

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.

Diffusion of Silver Diamine Fluoride Solution in Dentine: An In Vitro Study

OBJECTIVES

The aim of this research was to assess the diffusion dynamics of silver and fluoride ions after 38% silver diamine fluoride (SDF) solution application on dentine of varying thicknesses over 24 weeks.

METHODS

Bovine dentine discs of 5.5 mm in diameter were prepared and separated into 3 groups with thicknesses of 0.5 mm (group 1), 1.0 mm (group 2), and 1.5 mm (group 3). The diameter and number of dentinal tubules of discs were assessed. Each disc received a topical application of 0.05 mL 38% SDF solution. The deionised water in the tube was collected weekly for 24 weeks. The silver and the fluoride ion concentrations in the collected deionised water were determined. Generalised estimating equations was used to explore the potential effects of the key factors on the silver/fluoride diffusion.

RESULTS

The amount of silver and fluoride ion diffusion through dentine almost levelled off after 4 weeks and showed a decline trend over 24 weeks. The mean (SD) 24-week cumulative ion diffusion through dentine in groups 1, 2, and 3 was as follows: 20 (4) μg, 10 (2) μg, and 5 (1) μg for silver (P < .05) and 18 (2) μg, 13 (2) μg, and 7 (1) μg for fluoride (P < .05), respectively.

CONCLUSIONS

Silver and fluoride ion diffusion through dentine showed a decline trend over 24 weeks. The diameter and the number of dentinal tubules on dentine with different thicknesses affects the ion diffusion dynamics. This study provides indications on the pattern of silver/fluoride ions diffusion through dentine to pulp after 38% SDF application. An increased amount of silver/fluoride diffuses through dentine into the pulp with decreased remaining dentine thickness.

Photothermal Effect and Biomineralization of Black Phosphorus Nanosheet-Composited Hydrogel Boosts Synergistic Treatment of Dentin Hypersensitivity

Dentin hypersensitivity (DH), marked by exposed dentinal tubules, presents as a sharp toothache triggered by stimuli and subsides when the stimuli are removed. To address the limitations of current commercial desensitizers in terms of acid resistance, friction resistance, and stability, a black phosphorus nanosheet-composited methacrylate gelatin hydrogel (GelMA/BP) is developed for DH treatment, leveraging the synergistic effects of photothermal therapy and biomineralization. Incorporating the BP nanosheet provided GelMA/BP with a stable photothermal response and the continuous release of phosphate anions, which blocked dentinal tubules by converting light energy into heat and initiating biomineralization. In vitro desensitizing therapy showed that the dentinal tubule diameter in the GelMA/BP50 group (0-1.13 µm) is significantly reduced compared to that in the DH-model group (0-3.14 µm). The GelMA/BP50 group achieved an 86% tubule occlusion rate, with acid resistance of 80%, friction resistance of 76%, and long-term stability of 74%. In vivo studies further validated the efficacy of GelMA/BP50, showing a reduction in tubule diameter (0-0.37 µm) and an occlusion rate of 79%, which alleviated toothache and increased intake and weight. These results demonstrate that this desensitizing hydrogel acts as an effective dentinal tubule sealant, offering promising clinical benefits for the topical treatment of DH.

Clinical and radiographic evaluation of silver diamine fluoride versus mineral trioxide aggregate as indirect pulp capping agents in deeply carious first permanent molars a randomized clinical trial

AIM

Clinical and radiographic evaluation of SDF versus MTA as indirect pulp capping agents in deeply carious first permanent molars.

METHODOLOGY

This study was conducted on (30) first permanent molars indicated for indirect pulp capping (IPC) randomly allocated to either SDF or MTA groups (n = 15). The molars were finally restored with glass hybrid glass ionomer restoration. Clinical assessment was conducted at 3, 6, 9 and 12 months, while radiographic assessment was performed at 6 and 12 months using predetermined criteria. Data was statistically analyzed.

RESULTS

There was no statistically significant difference between both groups for all assessed clinical and radiographic parameters, including dentin bridge formation, at all follow-up periods. There was no evidence of clinical or radiographic failure in either group.

CONCLUSIONS

SDF showed a high success rate compared to MTA and can be considered a promising alternative IPC agent in permanent molars.

Combination of Silver Diamine Fluoride and Hall Technique for Caries Management in Primary Molars: A Randomized Controlled Trial

Aims and background

Combination of different noninvasive caries arresting approaches may improve the effectiveness and success rate of individual procedures for caries management. The purpose of this study was to evaluate clinical and radiographic success rate of a combination of 38% silver diamine fluoride (SDF) application and Hall technique (HT) for the management of dentinal caries in primary molars and compare it with conventional stainless steel crown (SSC) restoration.

Materials and methods

Children aged 4-8 years, having carious primary molars with the International Caries Detection and Assessment System (ICDAS) score of 5 or 6, were randomly assigned to treatment group A or B. Treatment group A (n = 25) received 38% SDF application and Hall crown, while group B (n = 25) received conventional SSC restoration. Follow-up was done at 1 month, 3, 6, 12, 24, and 30 months intervals.

Results

There was one case of major failure in group A (93.5% successful) while no case of major failure in group B (100% successful) and the difference was not statistically significant (p > 0.05). For minor failure (loss of SSC), the success rate was 91.3% in group B and 84.2% in group A, wherein the difference was not statistically significant (p > 0.05).

Conclusion

Conservative management of dentinal carious lesions with SDF and HT showed a similar success rate as compared to conventional operative procedures.

Clinical significance

This protocol can help reduce the clinical chair time and the need for deep sedation/general anesthesia in young children suffering from deep carious lesions with reversible pulpitis.

Trial registration number

CTRI/2020/07/026877, Clinical Trial Registry-India.

How to cite this article

Mittal M, Chopra R, Kumar A, et al. Combination of Silver Diamine Fluoride and Hall Technique for Caries Management in Primary Molars: A Randomized Controlled Trial. Int J Clin Pediatr Dent 2024;17(10):1114-1120.

In vitro biocompatibility of ammonia-free silver fluoride products on human dental pulp stem cells

OBJECTIVES

Silver fluoride (SF) is a preventive and therapeutic option for dental pathological processes involving structural alterations of the hard tissues, either during their formation or those caused by caries or other pathological reasons. This study aimed to compare the biological properties of two commercial SF products, one of them with ammonium (Riva Star; SDF) and the other ammonium-free (Riva Star Aqua; AgF), both with or without potassium iodide (KI), by the assessment of the cytotoxicity of the materials' eluates.

METHODS

Human dental pulp stem cells (hDPSCs) were obtained from healthy 18-23-year-old donors. Three dilutions were prepared for the tested materials (0.005%, 0.0005%, and 0.0001%). The following groups were assessed: (AgF, AgF+KI, SDF, SDF+KI, KI, negative control). A series of cytocompatibility assays were performed: MTT assay, IC50 assay, wound healing (migration) assay, cell cytoskeleton staining, analysis of cell apoptosis and necrosis, and reactive oxygen species production. The normality in the distribution of the data was previously confirmed via a Q-Q plot. Statistical significance was tested using one way ANOVA and Tukey's post hoc test.

RESULTS

The incorporation of KI improved the cytocompatibility of both SF products in terms of viability, migration, morphology, apoptosis, and reactive oxygen species production. This difference was higher in the AgF group. The lowest dilutions of SF+KI and AgF+KI showed a similar cytocompatibility to that of the control group (MTT assay (p > 0.05 after 24, 48, and 72 h of culture); migration assay (p > 0.05 after 24, 48, and 72 h of culture); reactive oxygen species production (p > 0.05 after 72 h of culture).

SIGNIFICANCE

Riva Star Aqua shows lower cytotoxicity than Riva Star on hDPSCs. It can be considered as a good alternative in the conservative treatment of dental caries and in the preservation and remineralisation of viable dentine tissue.

Silver Diamine Fluoride Renaissance in Paediatric Dentistry: A 24-Month Retrospective and Cross-Sectional Analysis

Background and Objectives: Silver diamine fluoride (SDF) has been incorporated into the treatment of dental caries in children, mainly in countries with high caries prevalence. In Europe, however, SDF started to gain popularity during the COVID-19 pandemic. This study aimed to investigate the efficacy of SDF and to evaluate dentists'/parents' acceptance of SDF use in paediatric patients treated in a German university setting. Materials and Methods: A retrospective analysis of all patients treated with SDF between 2017 and 2020 was carried out. Only teeth with no reported clinical/radiographic evidence of irreversible pulpal inflammation were included. The outcome measures were success, minor failures (caries progression, reversible pulpitis) and major failures (irreversible pulpitis, abscess). The treatment acceptance by dentists and the parents of SDF-treated children was cross-sectionally evaluated using questionnaires. Descriptive statistics and Kaplan-Meier survival analysis were performed. Results: A total of 93 patients (mean age 5.3 ± 2.9 years) with 455 treated teeth (418 primary/91.9%; 37 permanent/8.1%) were included and followed up for up to 24 months (19.9 ± 10.5 months). SDF was used for dental caries (98.2%) and hypersensitivity relief on MIH teeth (1.8%). Most teeth did not show any failure (total success 84.2%). A total of 5 teeth (1.1%) showed minor failures, and 67 teeth (14.7%) showed major failures (p = 0.001). Success/failure rates were not affected by patient compliance, gender, dentition, or operator (p > 0.05). In total, 30 questionnaires were collected from parents (mean age 36.8 ± 6.4 years). SDF was applied on anterior (n = 2/6.7%), posterior (n = 15/50%) and anterior/posterior teeth (n = 13/43.3%). At the 1-week follow-up, 80% of parents noticed black teeth discoloration. Treatment satisfaction was higher for posterior (95.2%) than for anterior teeth (36.4%; p < 0.001). In the 27 responses from clinicians, SDF was generally considered a viable option in paediatric dentistry (n = 23; 85%). Conclusions: SDF was found to be effective and well-accepted by parents and dentists for caries inactivation in a paediatric dentistry German university setting.

Pulp cell response to the application of silver diamine fluoride and potassium iodide on caries-like demineralized dentin

OBJECTIVES

To investigate the response of pulp cells to the application of silver diamine fluoride (SDF) and potassium iodide (KI) on demineralized dentin.

MATERIALS AND METHODS

The occlusal surfaces of human dentin discs (0.4 mm thick) with similar permeability were subjected to an artificial caries protocol, and then the discs were adapted into artificial pulp chambers. MDPC-23 cells were seeded on the healthy pulp dentin surface, while the demineralized surface was treated with SDF, KI, SDF + KI, or hydrogen peroxide (positive control-PC) (n = 8). The negative control (NC) received ultrapure water. After 24 h, cell viability (alamarBlue) and morphology (SEM) were evaluated. The extracts were then applied to new MDPC-23 cells seeded in culture plates to assess their viability and the formation of mineralized nodules (MN; Alizarin Red) after seven days. The data were analyzed using one-way analysis of variance/Tukey or Games-Howell tests (α = 5%).

RESULTS

SDF and PC significantly reduced the viability of cells seeded on discs (45.6% and 71.0%, respectively). Only cells treated with SDF or PC detached from the dentin substrate, while the remaining cells showed altered morphology. Cells in contact with extracts showed less reduction in viability, but it was still more toxic compared to NC. Only PC reduced MN deposition. SDF + KI or KI alone did not affect the cell response.

CONCLUSIONS

SDF applied alone showed a mild to moderate transdentinal cytotoxic effect on pulp cells. However, the combination of SDF + KI reduced the cytotoxic effects. Both materials used alone or in combination did not affect the mineralization ability of pulp cells.

CLINICAL RELEVANCE

Besides improving esthetic results, associating potassium iodide with silver diamine fluoride may reduce the transdentinal cytotoxic effects of this cariostatic agent on pulp cells.

Factors that influence parental satisfaction with SDF treatment in healthy children and those with special healthcare needs

Purpose

Silver diamine fluoride (SDF) is used as a caries management agent for the arrest of dentinal caries lesions. The purpose of this study was to evaluate the satisfaction with SDF treatment provided at a university pediatric dentistry clinic and to identify factors that may contribute to parental dissatisfaction.

Methods

We obtained retrospective data of children who received SDF treatment at our clinic from 1 February 2019 to 28 February 2021. Parents were contacted by phone to participate in a survey that evaluated their satisfaction with the treatment. Satisfaction was evaluated as a function of medical status, ease of treatment, outcome of SDF treatment, esthetics, and understanding of treatment goals and side effects using contingency tables and chi-square statistics.

Results

From 209 children who received SDF treatment, we were able to contact 91 parents by telephone, and 79 agreed to participate. Special healthcare needs (SHCN) patients were overrepresented in our sample, comprising 22.3% of all treated and 36.7% of participants. More than 90% were satisfied with the treatment, would do it again and would recommend it to others. Among the 49 children who complained of pain, SDF treatment resolved 82% of these complaints. In the subsample with follow-up in our clinic, approximately half of the treated teeth later received restorative treatment or were extracted, and the other half presented without further treatment. Some children received further treatment elsewhere. Parental dissatisfaction was related to staining of the anterior teeth (p = 0.04), the need for further treatment (p = 0.02) and a lesser understanding of side effects (p = 0.002).

Conclusion

Most parents were satisfied with SDF therapy as a dental treatment choice due to its easy application and desensitizing effects. Our findings indicate that parental understanding of the interim nature of the treatment and staining of the lesions is important to achieve parental satisfaction.

Annual review of selected scientific literature: A report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry

The Scientific Investigation Committee of the American Academy of Restorative Dentistry offers this review of the 2022 dental literature to briefly touch on several topics of interest to modern restorative dentistry. Each committee member brings discipline-specific expertise in their subject areas that include (in order of the appearance in this report): prosthodontics; periodontics, alveolar bone, and peri-implant tissues; dental materials and therapeutics; occlusion and temporomandibular disorders; sleep-related breathing disorders; oral medicine and oral and maxillofacial surgery; and dental caries and cariology. The authors focused their efforts on reporting information likely to influence the daily dental treatment decisions of the reader with an emphasis on innovations, new materials and processes, and future trends in dentistry. With the tremendous volume of literature published daily in dentistry and related disciplines, this review cannot be comprehensive. Instead, its purpose is to update interested readers and provide valuable resource material for those willing to subsequently pursue greater detail on their own. Our intent remains to assist colleagues in navigating the tremendous volume of newly minted information produced annually. Finally, we hope that readers find this work helpful in managing patients.

Effectiveness of silver diamine fluoride in indirect pulp capping in primary molars: A systematic review and meta-analysis

Introduction

Recently, clinical trials have assessed the effectiveness of Silver Diamine Fluoride (SDF) as an indirect pulp capping material (IPC) in primary teeth. This systematic review aimed to assess the evidence presented in these trials.

Data sources

A comprehensive search identified relevant studies through five electronic databases (PubMed, Scopus, ClinicalTrials.gov, ScienceDirect, and Cochrane). Search strategies were designed using the PICO model to identify all studies that investigated SDF as an IPC compared to calcium hydroxide (CaOH) or mineral trioxide aggregate (MTA). Quality assessment and Grading of Recommendations Assessment, Development, and Evaluation (GRADE) were used to assess the level of evidence.

Study selection

Four clinical trials were found to be suitable for inclusion in the qualitative synthesis and three studies were included in the quantitative analysis. Three studies compared SDF with CaOH and only one study compared SDF, CaOH, and MTA. Only one randomized controlled trial (RCT) had a low risk of bias, and the non-RCT study had a moderate risk of bias. The level of evidence based on the GRADE was low. Three out of four studies showed higher clinical and radiographic outcomes with SDF than with CaOH. One non-RCT study showed that SDF resulted in the least reparative dentin at the 6-months follow-up. The meta-analysis showed a non-significant difference between the SDF and CaOH groups (P = 0.36).

Conclusion

There is little evidence showing a higher clinical and radiographic outcome of SDF compared to CaOH as an IPC material in primary molars.

Clinical significance

This systematic review updates pediatric dentists regarding the effectiveness of using SDF as indirect pulp caping in primary teeth.

Dental Pulp Response to Silver-Containing Solutions: A Scoping Review

Dentists used silver-containing solutions for deep cavity disinfection before restoration. This review aims to identify the silver-containing solutions reported in the literature for deep cavity disinfection and summarize their effects on dental pulp. An extensive search was performed using the search words "(silver) AND (dental pulp OR pulp)" in ProQuest, PubMed, SCOPUS, and Web of Science to identify English publications on silver-containing solutions for cavity conditioning. The pulpal response to the included silver-containing solutions was summarized. The initial search identified 4112 publications and 14 publications met the inclusion criteria. Silver fluoride, silver nitrate, silver diamine nitrate, silver diamine fluoride, and nano-silver fluoride were used in deep cavities for antimicrobial purposes. Indirect silver fluoride application induced pulp inflammation and reparative dentine in most cases, and pulp necrosis in some cases. Direct silver nitrate application caused blood clots and a wide inflammatory band in the pulp, whilst indirect silver nitrate application caused hypoplasia in shallow cavities and partial pulp necrosis in deep cavities. Direct silver diamine fluoride application induced pulp necrosis, while indirect silver diamine fluoride application induced a mild inflammatory response and reparative dentine formation. No evidence of the dental pulpal response to silver diamine nitrate or nano-silver fluoride was available in the literature.

Time-dependent structural changes and hypermineralisation of artificially demineralised dentine following treatment with silver diammine fluoride and glass ionomer cement

OBJECTIVES

This study aimed to evaluate the change of mineral content in dentine lesions over time and examine the effectiveness of the combined treatment with silver diammine fluoride (SDF) and glass ionomer cement (GIC).

METHODS

Sixty bovine dentine specimens were divided into 4 groups: cont, Fuji, Safo, and Safo+Fuji. The specimens were imaged and measured using microcomputed tomography (microCT) at 7 time points: pre-demineralisation, after demineralisation for two weeks, immediately after treatment, 1 week, 2 weeks, 1 month, and 3 months after treatment. The 3-month group was evaluated with a light microscope, attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, and scanning electron microscope (SEM)/energy-dispersive X-ray spectroscopy (EDS). Data were analysed by Dunn's test and Wilcoxon signed rank test with Bonferroni correction for microCT, and Kruskal-Wallis test and two-way analysis of variance for EDS characterisation.

RESULTS

MicroCT images showed high mineral density beneath dentine lesions in Safo+Fuji. The mineral density at 600 μm in Safo+Fuji increased significantly over time, while Safo showed an opposite trend (adjusted p<0.005). In Safo+Fuji, EDS revealed significantly high energy of fluorine (p<0.05, at 300 μm) and a tendency towards high energy of calcium (p>0.05). However, Safo+Fuji showed lower energy of silver compared to Safo (p<0.001). ATR-FTIR revealed that phosphate groups had the highest peak at a depth between 300 and 400 μm in Safo+Fuji.

CONCLUSIONS

Safo+Fuji was effective in remineralising the deep lesion in dentine after one and three months, and a hypermineralisation zone generated beneath the lesion demonstrated additional benefit in this study.

CLINICAL SIGNIFICANCE

This long-term in vitro study showed that SDF+GIC treatment could strengthen the structure of decayed teeth when applied in the treatment of patients with advanced rampant caries.

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.

Radiographic Changes to Silver Diamine Fluoride Treated Carious Lesions after a Rinsing Step

Silver diamine fluoride (SDF) is radiopaque. This in vitro study compares the changes in the radiopacity of carious lesions after SDF application, potassium iodide (PI) application, and water rinse. Ten recently extracted human teeth were sectioned and divided into two groups (n = 10 in each group): Group 1 = SDF, Group 2 = SDF + PI. Teeth in Group 1 received SDF for 1 min and rinsed with 15 mL water. Group 2 received the same protocol with the addition of PI application for 1 min after SDF application. All samples were scanned with micro-computed tomography before SDF application, after SDF application, after PI application (group 2) and after water rinse. The radiopacity of the carious lesions increased significantly after SDF application in Group 1 and 2 (p < 0.017, p < 0.008, respectively). A significant increase in radiopacity after PI application was also observed in Group 2 (p < 0.008). Water rinsing significantly decreased the radiopacity in Group 1 and 2 (p < 0.017, p < 0.008, respectively), but the radiopacity remained significantly higher than the preoperative values (Group 1 p < 0.017, Group 2 p < 0.008). The radiopacity of carious lesions increases after SDF and SDF + PI applications. Water rinsing could reduce the radiopacity of SDF and SDF + PI treated carious lesions, and might reduce the content of SDF in carious lesions.

Characterization of silver diamine fluoride cytotoxicity using microfluidic tooth-on-a-chip and gingival equivalents

OBJECTIVE

This study aims to characterize the cytotoxicity potential of silver diamine fluoride (SDF) on dental pulp stem cells (DPSC) and gingival equivalents.

METHODS

DPSC cultured on 96-well plates was exposed directly to SDF (0.0001-0.01%) and cell viability (IC₅₀) quantified. Effect of SDF on DPSC viability under flow (with dentin barrier) conditions was evaluated using a custom-designed microfluidic "tooth-on-a-chip". Permeability of dentin discs (0.5-1.5 mm thickness) was evaluated using lucifer yellow permeation assay. Dentin discs were treated with 38% SDF (up to 3 h), and cell viability (live/dead assay) of the DPSC cultured in the inlet (unexposed) and outlet (exposed) regions of the pulp channel was evaluated. To assess the mucosal corrosion potential, gingival equivalents were treated with 38% SDF for 3 or 60 min (OECD test guideline 431) and characterized by MTT assay and histomorphometric analysis.

RESULTS

DPSC exposed directly to SDF showed a dose-dependent reduction in cell viability (IC₅₀: 0.001%). Inlet channels (internal control) of the tooth-on-a-chip exposed to PBS and SDF-exposed dentin discs showed> 85% DPSC viability. In contrast, the outlet channels of SDF-exposed dentin discs showed a decreased viability of< 31% and 0% (1.5 and ≤1.0 mm thick dentin disc, respectively) (p < 0.01). The gingiva equivalents treated with SDF for 3 and 60 min demonstrated decreased epithelial integrity, loss of intercellular cohesion and corneal layer detachment with significant reduction in intact epithelial thickness (p < 0.05).

SIGNIFICANCE

SDF penetrated the dentin (≤1 mm thick) inducing significant death of the pulp cells. SDF also disrupted gingival epithelial integrity resulting in mucosal corrosion.

A Review of the Protocol of SDF Therapy for Arresting Caries

Objective

The aim of this work was to review the protocol of the use of silver diamine fluoride (SDF) for arresting caries, specifically the application time.

Method

Two researchers searched manufacturers’ instructions, YouTube videos, and 5 databases (Embase, Medline, PubMed, Scopus, and Web of Science). Manufacturers’ instructions, videos from national dental organisations, and peer-reviewed journal articles that published the SDF application protocol in English for arresting caries were selected.

Results

The review included 14 protocols from 15 publications from 4 manufacturers, 3 dental associations, and 7 author teams (one team had 2 articles). The American Dental Association and the British Society of Paediatric Dentistry provided their SDF application protocols on YouTube. The American Academy of Paediatric Dentistry and 7 author teams published their protocols in journal articles. Seven publications suggested an SDF application time of 60 seconds. Seven publications suggested a time range of 10 seconds to 240 seconds. Two publications suggested caries excavation, but 4 publications suggested no caries excavation before SDF application. The procedures from at least 5 publications involved protecting the gingiva with petroleum jelly, isolating the carious tooth with cotton rolls, drying the carious lesion with a 3-in-1 syringe, applying SDF solution with a micro brush for 60 seconds, removing excess SDF solution with gauze, and applying fluoride varnish to the SDF-treated lesion.

Conclusions

Although the SDF application protocol is simple and straightforward, the published protocols could be different. Most publications suggested an SDF application time of 60 seconds, which can be long, particularly for young children and older adults.