Global research interest regarding silver diamine fluoride in dentistry: A bibliometric analysis

OBJECTIVE

This study aimed to investigate the global research interest regarding silver diamine fluoride (SDF) in dentistry using a bibliometric approach.

METHODS

A literature search was conducted in the Web of Science Core Collection database to identify studies related to SDF. Bibliometric data from the selected publications were exported and analysed using the Bibliometrix Biblioshiny R-package software. The type of research and main contents of the publications were summarised. One-way analysis of variance was used to detect the differences in the citation counts of the publications with various types of research. In addition, Google Trends was used to investigate the popularity of the search term "silver diamine fluoride".

RESULTS

A total of 259 publications were included and analyzed. The annual scientific production of SDF studies increased significantly per year in the past five years, and it mainly concerned dental caries. The three main types of research were laboratory/animal study (n = 114, 44%), review/guideline (n = 56, 22%), and clinical trial (n = 44, 17%). The citation count related to the type of research (p < 0.01). The citation count of clinical trials was significantly higher than that of laboratory/animal studies (p < 0.05). As quantified via data from Google Trends, the search popularity of "silver diamine fluoride" also increased significantly.

CONCLUSION

Based on the results of bibliometric analysis, global research interest regarding SDF has rapidly increased in recent years.

CLINICAL SIGNIFICANCE

This paper presents an overview of scientific evidence and impact of SDF use in dentistry. SDF attracts a growing interest globally and there has been a steady increase in scientific research into its use in dental practice.

Predicting Treatment Nonresponse in Hispanic/Latino Children Receiving Silver Diamine Fluoride for Caries Arrest: A Pilot Study Using Machine Learning

Objectives: Silver diamine fluoride (SDF) is a nonsurgical therapy for the arrest and prevention of dental caries with demonstrated clinical efficacy. Approximately 20% of children receiving SDF fail to respond to treatment. The objective of this study was to develop a predictive model of treatment non-response using machine learning. Methods: An observational pilot study (N = 20) consisting of children with and without active decay and who did and did not respond to silver diamine fluoride provided salivary samples and plaque from infected and contralateral sites. 16S rRNA genes from samples were amplified and sequenced on an Illumina Miseq and analyzed using QIIME. The association between operational taxonomic units and treatment non-response was assessed using lasso regression and artificial neural networks. Results: Bivariate group comparisons of bacterial abundance indicate a number of genera were significantly different between non-responders and those who responded to SDF therapy. No differences were found between non-responders and caries-active subjects. Prevotella pallens and Veillonella denticariosi were retained in full lasso models and combined with clinical variables in a six-input multilayer perceptron. Discussion: The acidogenic and acid-tolerant nature of retained bacterial species may overcome the antimicrobial effects of SDF. Further research to validate the model in larger external samples is needed.

"I guess it looks worse to me, it doesn't look like there's been a problem solved but obviously there is": a qualitative exploration of children's and their parents' views of silver diamine fluoride for the management of carious lesions in children

Background

Despite growing evidence to support the use of silver diamine fluoride (SDF) for managing carious lesions, and the increased interest in SDF worldwide, uptake in the UK remains limited. This study explored parents’ and children’s views and acceptability of SDF for the management of carious lesions in children.

Methods

Eleven semi-structured face-to-face interviews were conducted with 11 parent–child dyads recruited from patients attending Dundee Dental Hospital and School. Interviews were transcribed verbatim, coded and thematically analysed.

Results

Previous dental experience varied across all child participants. Of the 11 children, five had undergone general anaesthesia (GA) for multiple primary tooth extractions. Two had received SDF treatment. Child participants expressed concerns about being picked on by their peers, if they had discoloured anterior teeth. Younger children appeared less concerned about the discolouration and child’s gender did not appear to influence parents’ decision-making, nor the child’s preferences regarding the use of SDF. Parents considered SDF to be particularly useful for anxious or uncooperative children but raised concerns about potential bullying at schools due to the unacceptable dental aesthetics when SDF is applied to anterior teeth. They believed they may be judged by others as neglecting their child’s oral health due to the black staining. Both parents and children were more accepting of the SDF when applied to less-visible posterior teeth. Parents accepted the use of SDF if such treatment avoided extractions under GA.

Conclusion

Despite the unfavourable aesthetics of SDF (black staining), parents appreciated SDF treatment, especially for uncooperative or younger children. However, both parents and children shared concerns about bullying at schools as a consequence of the black staining. Raising awareness about SDF was identified as one approach to encourage the uptake of SDF.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-021-01730-w.

Remineralising dentine caries using an artificial antimicrobial peptide: An in vitro study

OBJECTIVE

To investigate the antibacterial and remineralising effects of a novel dual-action antimicrobial peptide, GA-KR12, on artificial dentine caries.

METHODS

Human dentine blocks with artificial carious lesions were allocated to two groups - Group 1: dentine blocks treated with the novel antimicrobial peptide GA-KR12 twice daily; Group 2: dentine blocks received water as the negative control. Two groups underwent Streptococcus mutan biofilm-remineralisation cycles at 37 °C for 7 days. The morphology, viability and growth kinetics of the S. mutans biofilm were evaluated by scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM) and colony-forming unit (CFU) counting, respectively. The dentine blocks' lesion depths and mineral loss, changes in chemical structure, dentine surface morphology and crystal characteristics were determined using micro-computed tomography, Fourier transform infrared (FTIR), SEM and X-ray diffraction (XRD), respectively.

RESULTS

The surface of the dentine blocks in Group 1 was partially covered by S. mutans with damaged cell structure. Group 2 showed affluent growth of S. mutans covering the dentine surface when compared to Group 1. The dead-to-live ratio of Group 1 and Group 2 were 0.78 ± 0.01 and 0.47 ± 0.08, respectively (p < 0.001). The Log CFUs of Group 1 and Group 2 were 7.14 ± 0.30 and 8.24 ± 0.20, respectively (p < 0.001). The lesion depths of Group 1 and Group 2 were 109 ± 1 µm and 135 ± 3 µm, respectively (p < 0.001). The mineral loss of Group 1 and Group 2 were 0.59 ± 0.08 gHApcm^-3 and 0.81 ± 0.07 gHApcm^-3, respectively (p < 0.001). FTIR showed the amide I-to-hydrogen phosphate (HPO₄^2-) ratios of Group 1 and Group 2 were 0.25 ± 0.05 and 0.39 ± 0.05 (p < 0.001), respectively. SEM images showed Group 1 had less exposed dentine collagen fibres than Group 2. The XRD revealed that the hydroxyapatite in Group 1 was well crystalised.

CONCLUSION

This study demonstrated that the novel antimicrobial peptide GA-KR12 inhibited the growth of S. mutans biofilm and enhanced the remineralisation of artificial dentine caries.

Effects of Different Application Times of Silver Diamine Fluoride on Mineral Precipitation in Demineralized Dentin

Silver diamine fluoride (SDF) is a cost-effective method for arresting active dental caries. However, the limited cooperation of patients may lead to an SDF application time that is shorter than the recommended 1-3 min for carious lesions. Therefore, the aim of this study was to assess the effect of different application times of SDF on the degree of mineral precipitation in demineralized dentin. Demineralized dentin specimens from permanent maxillary molars were treated by applying 38% SDF for 30, 60, or 180 s. Water was applied in the control group. The specimens were immersed in simulated body fluid for 2 weeks, and the mineral precipitation in demineralized dentin was then analyzed using FTIR-ATR, SEM-EDX, and synchrotron radiation X-ray tomographic microscopy (SRXTM). The FTIR-ATR results showed a significant increase in mineral precipitation in the 180 s group after 1 week. However, after 2 weeks, the SRXTM images indicated comparable mineral density between the 30, 60, and 180 s groups. The precipitation of silver chloride and calcium phosphate crystals that occluded dentinal tubules was similar in all experimental groups. In conclusion, an application time of either 30, 60, or 180 s promoted a comparable degree of mineral precipitation in demineralized dentin.

The effect of the combined use of silver diamine fluoride and potassium iodide in disrupting the plaque biofilm microbiome and alleviating tooth discoloration: A systematic review

Silver diamine fluoride (SDF) is used in minimally invasive dentistry for arresting dental caries. However, discoloration of teeth is a significant side effect that has limited the use of SDF. Hence, the application of potassium iodide (KI) following SDF has been proposed to ameliorate the staining. Although antimicrobial activity is one of the major mechanisms of the caries-arresting effect of SDF, the antimicrobial potency of SDF/KI combination is unclear. Thus, the primary objective of this systematic review was to appraise the studies on the antimicrobial efficacy of SDF/KI combination on cariogenic microbes. The secondary objective was to summarize the evidence on the potential of KI in reducing the discoloration associated with the application of SDF. Electronic databases of Medline via PubMed, Cochrane Library, Web of Science, and EBSCO host were searched for English language manuscripts from January 2005 to 15th November 2020. The reference lists of these manuscripts were manually searched for additional studies. Twelve studies were included in the final analysis, seven of which have investigated the antimicrobial efficacy of SDF/KI, and the rest have examined the anti-staining potential of KI. The exploratory findings from the reviewed articles revealed the promising antimicrobial potential of SDF/KI on cariogenic microbes associated with dentine caries. There is, however, contradictory evidence on the effect of SDF/KI on tooth color. The reviewed in-vitro studies indicated significant effectiveness of KI in preventing staining. A clinical trial on primary dentition showed 25% reduction in the incidence of staining by SDF after applying KI, while a clinical study on root caries in adults showed no significant effect. Within the methodological limitations of this review, we conclude that for arresting dental caries, SDF could be combined with KI, as there may be a lower likelihood of staining. Further, well-designed clinical trials on the antimicrobial and anti-staining effect of SDF/KI are needed to obtain more robust evidence.

The effect of reduced glutathione on the toxicity of silver diamine fluoride in rat pulpal cells

Introduction

Due to its ability to arrest untreated dental caries, silver diamine fluoride (SDF) has been advocated for indirect pulp capping procedures. However, the high concentrations of silver and fluoride in SDF raise concerns about its biocompatibility to pulpal tissues.

Objectives

This study aimed to investigate the effect of SDF on the viability, alkaline phosphatase (ALP) activity, and morphology of pulpal-like cells (RPC-C2A) and to evaluate the influence of reduced glutathione (GSH) on SDF-induced cytotoxicity and deposit formation on dentin.

Methodology

The cytotoxicity of diluted 38% SDF solutions (10-4 and 10-5), with or without the addition of 5 mM or 50 mM GSH, was evaluated at 6 and 24 hours. Cell viability was detected using WST-8 and the effect on ALP activity was performed using an ALP assay kit. Cell morphology was observed using a phase-contrast microscope. Scanning electron microscopy analysis was conducted to evaluate the effect of GSH incorporation or conditioning on SDF-induced deposit formation on dentin discs. Cytotoxicity data were analyzed by two-way analysis of variance (ANOVA) and Tukey post hoc tests (p<0.05).

Results

There were significant differences between the groups. The results demonstrated that all tested SDF dilutions caused a remarkable cytotoxic effect, while the addition of GSH prevented SDF-induced damage at 6-hour exposure time in the higher dilution of SDF. Dentin treated with plain SDF or GSH-incorporated SDF solution showed deposit formation with occluded dentinal tubules, unlike the other groups.

Conclusion

SDF severely disturbed the viability, mineralization-ability, and morphology of pulpal-like cells, while controlled concentrations of GSH had a short-term protective effect against SDF-induced damage. GSH showed an inhibitory effect on SDF-induced dentinal deposit formation. Further research is warranted to evaluate the effect of GSH on caries-arresting, anti-hypersensitivity, and antibacterial functions of SDF.

Monitoring silver diamine fluoride application with optical coherence tomography

The objective of this study was to investigate the use of optical coherence tomography (OCT) for monitoring changes in the structure of caries lesions overtime after treatment with silver diamine fluoride (SDF). Artificial caries lesions were formed on dentin bovine blocks. Each block was partitioned into 5 windows: one lesion was covered by nail varnish as control (LC), one sound window was covered with nail varnish (SC), one sound window was exposed to SDF (SCT), one lesion received 2 applications of SDF (L2), while the other lesion received one application of SDF (L1). Each window was scanned using OCT before SDF application, and every week subsequently, for 12 weeks after initial SDF treatment. Parameters such as mean intensity and the width of the peak of increased reflectivity located at the sample surface and the intensity at a depth of 180-μm were monitored. High-resolution microscopy was also used to for the analysis of selected samples. Changes in the parameters measured showed significant changes on dentin lesions after SDF application. OCT resolved structural changes after SDF application as well as changes overtime. High resolution microscopy images confirm penetration of SDF into the samples. Such changes can potentially be monitored to determine if and when re-application of SDF is needed.

Effects of silver diamine fluoride preparations on biofilm formation of Streptococcus mutans

Effects of silver diamine fluoride preparations (SDFs) on cariogenic biofilm formation on root dentin (RD) were investigated. Streptococcus mutans (S. mutans) biofilms were formed on bovine RD blocks coated with one of three the SDFs (38%-SDF, 3.8%-SDF and 35%-SDF+potassium-iodide; SDF+KI) and a non-coated Control which were quantified (spectrometric-measurement) and thickness measured (optical coherence tomography) after 20 h. Bacterial viability test (BacLight) and biofilm-morphometry (SEM) of 2 h biofilms were also performed. The amounts of biofilms (bacteria and water insoluble glucan) and the thickness of biofilm were minimum on 38%-SDF specimen; 3.8%-SDF and SDF+KI had significantly more than that, but had significantly less than Control (p<0.05). Most S. mutans cells found dead and morphology damaged by 38%-SDF. Some dead bacteria and remarkably damaged biofilms were observed in case of 3.8%-SDF and SDF+KI. Inhibition potential of 3.8%-SDF and SDF+KI on S. mutans biofilm formation is almost similar, although not equivalent to 38%-SDF.

Microbial population shift and metabolic characterization of silver diamine fluoride treatment failure on dental caries

The objective of this pilot study was to describe the microbial profiles present in the plaque and saliva of children who continued to develop new carious lesions following treatment with silver diamine fluoride ("nonresponders") compared to caries active, caries-free, and children immediately receiving SDF treatment for untreated caries in order to identify potential microbial differences that may relate to a re-incidence of caries. Saliva and plaque samples from infected and contralateral sites were obtained from twenty children who were either caries free, had active carious lesions, were caries active and received SDF treatment immediately before sampling, or had previously received SDF treatment and developed new caries. In total, 8,057,899 Illumina-generated sequence reads from 60 samples were obtained. Reads were processed using the Quantitative Insights Into Microbial Ecology pipeline. Group differences were assessed using Analysis of Variance Models and Tukey Honest Significant Differences. To identify significant taxa between treatment groups, Linear discriminant analysis Effect Size (LefSe) and Analysis of Differential Abundance Taking Sample Variation Into Account were used. Differential abundant analysis indicated that members of the Lachnospiraceae family were significantly enriched in non-responders and the genus Tannerella and species Granulicatella adiances were also highly abundant in this group. LefSe analysis between non-responders and SDF-treated groups revealed that genera Leptotrichia and Granulicatella were enriched in non-responders. We observed the highest abundance of phosphotransferase system and lowest abundance of lipopolysaccharide synthesis in non-responders. The microbiome in dental biofilms is responsible for initiation and progression of dental caries. SDF has been shown to be effective in arresting the progression carious lesions, in part due to its antimicrobial properties. Findings suggest that the differential abundance of select microbiota and specific pathway functioning in individuals that present with recurrent decay after SDF treatment may contribute to a potential failure of silver diamine fluoride to arrest dental caries. However, the short duration of sample collection following SDF application and the small sample size emphasize the need for further data and additional analysis.

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

BACKGROUND

There has been renewed interest in the use of silver diamine fluoride (SDF) for the management of carious lesions in high-risk groups. Previous studies have found a difference in clinical efficacy among different concentrations of SDF and discrepancies between ionic concentrations of fluoride (F) and silver (Ag) in SDF preparations. The aim of this study was to measure the free F, Ag ion concentrations and pH of a variety of commercially available SDF preparations.

METHODS

Seven SDF products used globally were evaluated for F and Ag ion concentrations using a calibrated ion-selective electrode and optical emission spectrometry respectively. Acidity was determined with a pH electrode.

RESULTS

The 30% SDF solution contained almost half the F concentration and a much higher Ag concentration than expected (16 343 ppmF and 246 000 ppmAg). Comparatively, the mean F concentration of the remaining six 38% solutions was 74 802 ppm (expected mean 44 800 ppm) ranging from 36 457 ppm to 120 760 ppm. The mean Ag concentration was 326 000 ppm (expected mean 253 870 ppm) and ranged from 246 000 ppm to 425 451 ppm. All solutions were found to be neutral or mildly alkaline in nature (pH 7-10.3).

CONCLUSIONS

Wide variations between claimed and measured F and Ag ion concentrations exist among the different brands of commercially available SDF products.

Indirect caries-preventive effect of silver diamine fluoride on adjacent dental substrate: A single-section demineralization study

This study assessed the indirect effect of 38% silver diamine fluoride (SDF) on demineralization of adjacent untreated sound and pre-demineralized enamel and dentine using a single-section model for digital transverse microradiography (TMR-D). Forty-eight bovine dentine single sections were demineralized, stratified (n = 12) according to integrated mineral loss (ΔZ), and treated with SDF or deionized water (DIW). Each "treated dentine" section was attached between untreated sound and pre-demineralized enamel or dentine and then subjected to demineralization. ΔZ and lesion depths (LD) of all specimens at baseline, 24 and 48 h demineralization, and after treatment of "treated dentine" were quantified using TMR-D. Fluoride in the demineralization solution of SDF clusters was determined using an ion-selective electrode. ΔZ and LD of sound and ΔZ of pre-demineralized enamel adjacent to SDF-treated dentine did not increase over time. All untreated dentine demineralized significantly; however, ΔZ of sound dentine adjacent to SDF-treated specimen was still significantly lower than control. SDF-treated dentine remineralized and released fluoride even after 48 h. Consistent with clinical findings, when applied only to demineralized teeth in this chemical model, 38% SDF completely inhibited demineralization in adjacent untreated sound enamel. Demineralization prevention was observed to a lesser extent in adjacent pre-demineralized enamel but not in dentine.

Antibacterial silver-containing mesoporous bioglass as a dentin remineralization agent in a microorganism-challenged environment

OBJECTIVES

To provide a suitable material capable of treating dentin hypersensitivity with simultaneous active antibacterial activity.

METHODS

We developed silver-containing mesoporous bioglass (MBG-Ag) using the sol-gel technique, which loaded silver nanoparticles as promising bacteriostatic agents. The MBG-Ag with a powder-to-liquid ratio of 0.5 g: 0.01 mL were uniformly mixed with 20 %, 30 %, and 40 % phosphoric acid for 5, 10 and 20 min, respectively. Furthermore, we evaluated the occlusion efficiency, depth of penetration, and antibacterial activity of dentin specimens by simulating a Streptococcus mutans (S. mutans) infection on dentin. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) were used to characterize the powders and assess tubule occlusion. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the MBG-Ag against S. mutans were determined via time-killing curves and colony formation assays.

RESULTS

The MIC ranged from 2.5 to 5 mg/mL, and the MBC ranged from 5 to 10 mg/mL. The highest dentinal tubule occlusion efficiency was over 90 %. The colony formation assay confirmed that 5 mg/mL MBG-Ag mixed with phosphoric acid reached the bactericidal concentration.

CONCLUSION

The MBG-Ag 40PA achieved a good occlusion efficiency and deep apatite precipitation in a short time, implying its superiority in clinical applications.

CLINICAL RELEVANCE

The MBG-Ag formed in this study is a promising candidate for the treatment of demineralized dentin and confers antibacterial effects on the remineralized dentin surface against S. mutans.

Caries arrest effectiveness of silver diamine fluoride compared to alternative restorative technique: randomized clinical trial

OBJECTIVE

This RCT study assessed and compared the effect of a biannual application of 38% silver diamine fluoride (SDF) with alternative restorative technique (ART) on arresting caries in primary dentition.

METHODS

The RCT was conducted over a period of 12 months and included 79 healthy children (237 primary teeth), aged 3-8 years, selected from the University Pediatric Dentistry outpatient clinics, with at least one primary asymptomatic tooth with active dentinal occlusal/labial lesions. Children were randomly assigned to SDF application or ART treatment. Visual and tactile examinations were used after 6 and 12 months to assess the activity of the carious lesions using the ICDAS II.

RESULTS

At 6- and 12-month-evaluation periods, no statistically significant differences in lesions arrest were found between SDF and ART groups (P = 1.000). Considering the frequency of arrested caries between the test groups at 6 and 12 months, no significant differences were observed between anterior and posterior lesions, as well as between the maxillary and mandibular lesions. When comparing the working time for the two treatments, the median time for those treated with SDF was 3.3 min, compared to 14.4 min for ART and was statistically significant (P < 0.0001).

CONCLUSION

Both SDF and ART are, indeed, effective for arresting caries. However, the chair-time management required for SDF is significantly shorter compared to ART. Taking into consideration the present evidence, the best decision regarding disease management and application of SDF or ART is to be made by the dentist and the patient/parent, recognizing individuals' differences and preferences.

Effect of silver diammine fluoride and glass ionomer on remineralisation of natural dentine caries

OBJECTIVES

Silver diammine fluoride (SDF) is a caries-arresting agent for dentine lesions. This study investigated the effect of application frequency of SDF when used with glass ionomer cement (GI) for remineralising carious dentine.

METHODS

Freshly extracted human posterior teeth with advanced caries were used. After superficial removal of infected dentine, single (G3), double (G4), triple (G5) applications of SDF (Advantage Arrest SDF 38 %) followed by a layer of GI (GC Fuji IX GP) were compared to no treatment (negative control-G2), and GI only (G1). All teeth were stored in artificial saliva between treatments and for 2-weeks after final treatment. Micro-computed X-ray tomography (NSI) scans were obtained at each stage and analysed to plot mineral density-depth profile, lesion depth (LD) and mineral loss (ΔZ). Data was statistically analysed at a significance level of 0.05.

RESULTS

Mean LD values were 837 μm, 735 μm, 841 μm, 1008 μm, 707 μm at baseline and 785 μm, 727 μm, 712 μm, 855 μm, 639 μm after treatment for groups G1 to G5, respectively. Mean ΔZ values were 6327 vol%μm, 5995 vol%μm, 10014 vol%μm, 7192 vol%μm, 5649 vol%μm at baseline and 3686 vol%μm, 5126 vol%μm, 5539 vol%μm, 2327 vol%μm, 3218 vol%μm after treatment for groups G1 to G5, respectively. Paired t-test showed that LD and ΔZ changed significantly within all groups from baseline to treatment weeks following storage (p < 0.05) except LD in the control (p > 0.05). ANCOVA showed significant difference among groups in net lesion depth recovery and net mineral gain (p < 0.05), and G3 and G4 showed the highest mineral gains.

CONCLUSION

One or two applications of SDF prior to placement of GI, were effective in remineralising advanced dentine lesions, while additional applications, when combined with GI, did not demonstrate additional benefit in this study.

CLINICAL SIGNIFICANCE

This short-term laboratory research study showed that one or two applications of SDF followed by GI coverage could remineralise advanced dentine caries in the presence of artificial saliva. This procedure carries potential in the treatment of difficult lesions where conventional restorations would require significant tooth structure removal through traumatic procedures.

Impact of graphene oxide and silver diamine fluoride in comparison to photodynamic therapy on bond integrity and microleakage scores of resin modified glass ionomer cement to demineralized dentin

AIM

To evaluate the impact of graphene oxide (GO) and silver diammine fluoride (SDF) in comparison to photodynamic therapy (PDT) on adhesive bond integrity and microleakage scores of resin-modified glass ionomer cement (RMGIC) to demineralized dentin.

METHODS

80 non-carious and atraumatic third molars were mounted inside the segments of polyvinyl pipes. Exposure, homogenization, and polishing of dentinal tubules was performed. 20 specimens were left unconditioned and classified a group 4. Exposure of acetic acid was done to 60 specimens and randomly allocated into 3 groups. Group 1 specimens were treated with 0.25 % GO; group 2 specimens were treated with 3.8 % SDF; and group 3 specimens were exposed to PDT. The bonding of all samples to RMGIC was performed by light curing and universal testing machine was utilized for testing shear bond strength (SBS). For failure modes, an optical microscope at 40x magnification was used to observe the debonded interfaces. For microleakage, all the specimens were submerged in 2% methylene blue for 1 day and observed under a digital microscope. The post hoc Tukey and analysis of variance (ANOVA) were used to examine SBS. A p-value of ≤0.05 was considered statistically significant.

RESULTS

Group 2 showed the highest bond strength (3.8 % SDF + RMGIC + DD - 15.27 ± 2.19 MPa). Groups 1 (0.25 % GO + RMGIC + DD - 14.11 ± 3.82) and 2 showed comparable results of SBS, which was significantly higher when compared with other research groups (p < 0.05). According to the post hoc Tukey test, the SBS scores of treatment groups exhibited statistically significant values as compared to the control group (p < 0.05). Group 2 samples showed the least microleakage mean score (0.8 ± 0.42), followed by group 1 specimens (1.02 ± 0.88). The comparable microleakage mean scores were demonstrated by the samples in group 1 and 2 (p < 0.01). According to one-way ANOVA, a significant difference was observed in microleakage scores among experimental groups (p < 0.01).

CONCLUSION

Improved bond strength and marginal microleakage scores were demonstrated by the demineralized dentin treated with 0.25 % graphene oxide and 3.8 % silver diamine fluoride when bonded to resin-modified glass ionomer cement. The application of methylene blue photosensitizer for photodynamic therapy undermined the adhesive bond strength applied on demineralized dentin.

Enhanced silver diamine fluoride therapy using the PILP method -A nanoindentation study

The aim of this study was to evaluate the feasibility of applying the polymer-induced liquid-precursor (PILP) method to enhance silver diamine fluoride (SDF) therapy. One hundred forty micrometer deep artificial caries lesions were treated with (A) 38% SDF solution and (B) 38% SDF containing poly-L-aspartic acid (pASP). Changes in the nanomechanical profile across the lesion were evaluated. Hydrated artificial lesions had a low reduced elastic modulus (0.3 GPa) and nanohardness (0.02 GPa) region extending about 100 μm into the lesion, with a gradual linear increase to about 168 μm where the values plateaued to around 18 GPa/1.0 GPa. Topical application of SDF resulted in significantly recovered properties (p<0.001). SDF containing pASP resulted in greater nanomechanical properties compared to SDF alone, showing similar sloped regions up to 96 μm, then SDF alone dropped while SDF containing pASP continued at a modest slope until reaching normal at 144 μm. This nanoindentation study shows enhanced SDF therapy using the PILP method.

Effects of mechanical abrasion challenge on sound and demineralized dentin surfaces treated with SDF

This study evaluated the effect of mechanical abrasion on the surface integrity, color change (ΔE) and antibacterial properties of demineralized and sound dentin surfaces treated with silver-diammine-fluoride (SDF). The dentin specimens were divided into two groups: sound and demineralized dentin, then divided into three sub-groups, control (no-treatment), SDF, and SDF + potassium-iodide (KI). Each sub-group was further divided into two groups, one exposed to mechanical brushing and the other without brushing. Specimens were analyzed for the ΔE, surface roughness/surface loss and antibacterial properties (CFU, optical density and fluorescent microscope). Repeated Measures ANOVA was used for statistical analysis of color change while one-way ANOVA was used for CFU analysis. SDF and SDI + KI groups showed significant reduction in ΔE with brushing in the sound dentin group unlike the demineralized group. The surface roughness values were higher for both SDF and SDF + KI groups but roughness values significantly decreased after brushing. Both SDF and SDF + KI groups revealed significantly less surface loss than control. The SDF group showed high anti-bacterial effect after brushing, unlike SDF + KI group. So, we concluded that mechanical brushing improved the esthetic outcome. While, SDF and SDF + KI could protect the dentin surface integrity. SDF-treated dentin possesses an antibacterial property even after mechanical brushing.

The effect of silver diamine fluoride in preventing in vitro primary coronal caries under pH-cycling conditions

OBJECTIVES

This study investigated the ability of SDF, and its individual components, silver (Ag⁺) and fluoride (F^-) ions, in preventing enamel demineralization under pH-cycling conditions in the presence or absence of twice-daily fluoride application.

DESIGN

Polished human enamel specimens were assigned to five treatment groups (n = 36 per group): SDF (38 %); SDF followed by application of a saturated solution of potassium iodide (SDF + KI); silver nitrate (AgNO₃; silver control, 253,900 ppm Ag); potassium fluoride (KF; fluoride control, 44,800 ppm F); deionized water. Treatments were applied once. Specimens in each treatment group were divided into two subgroups (n = 18). During the subsequent 7-day pH-cycling phase, specimens were treated twice daily with either 275 ppm fluoride as sodium fluoride or deionized water, immediately before and after a 3-h cariogenic challenge with exposure to artificial saliva at all other times. Changes in color, Vickers surface microhardness (SMH), transverse microradiography (TMR) was calculated. Data were analyzed using two-way ANOVA.

RESULTS

In both models, SDF, SDF + KI and KF were superior in inhibiting demineralization compared to AgNO₃ and deionized water (p < 0.0001). There was no statistically significant difference between SDF, SDF + KI and KF with twice daily fluoride treatments (p > 0.8). However, KF was more effective in preventing demineralization than SDF and SDF + KI in the absence of fluoride treatments (p = 0.0002). KI did not affect the ability of SDF to prevent demineralization (p > 0.4).

CONCLUSION

SDF and SDF + KI appears to be an effective option in preventing primary coronal caries.

Contemporary restorative ion-releasing materials: current status, interfacial properties and operative approaches

Minimally invasive (MI) concepts in restorative dentistry in the year 2020 request from the practitioner not only a scientifically supported rationale for carious tissue removal/excavation and defect-oriented, biological cavity preparation, but also a deep understanding of how to ensure a biomechanically stable and durable restoration in different clinical situations by applying different restorative options. Bio-interactive materials play an increasingly relevant role, as they not only replace diseased or lost tissue, but also optimise tissue mineral recovery (among other properties) when used in restorative and preventive dentistry. Indeed, this is of certain interest in MI restorative dentistry, especially in those cases where gap formation jeopardises the integrity of the margins along resin composite restorations, causing penetration of bacteria and eventually promoting the formation of secondary caries. Recently, the interest in whether ion-releasing materials may reduce such biofilm penetration into margin gaps and reduce such a risk for development and propagation of secondary caries is growing significantly among clinicians and scientists. The aim of this article was to explore mechanisms involved in the process that allow mineral deposition at the interface between such materials and dentine, and to describe how conventional 'bioactive' restorative materials currently available on the market may benefit treatments in MI dentistry.

Effect of silver diamine fluoride and proanthocyanidin on resistance of carious dentin to acid challenges

The aim of this study was to evaluate the effect of silver diamine fluoride and grape seed extract on the microstructure and mechanical properties of carious dentin following exposure to acidic challenge. Ninety-eight molars with occlusal caries were used. In the control group the specimens were kept in distilled water. In the GSE group, the specimens were immersed in 6.5% grape seed extract solution for 30 minutes. In the SDF group, the specimens were immersed in 30% SDF solution for 4 minutes. In the GSE+SDF group, the specimens were immersed in 6.5% grape seed extract solution for 30 minutes and then exposed to 30% SDF solution for 4 minutes. All the groups underwent pH cycling model for 8 days. Microhardness measurements were taken at the baseline before surface treatments and after pH cycling. Elastic modulus was measured, after pH cycling. In the control group, the final hardness was significantly lower than the initial hardness (P = 0.001). In the SDF group, the final hardness was significantly higher than the initial hardness (P < 0.001). There was no significant difference between the initial and final hardness values in the GSE and GSE + SDF groups (p = 0.92, p = 0.07). The H₁-H₀ in the SDF group was significantly higher than the other groups (P<0.05). Moreover, elastic modulus of the experimental groups except GSE+SDF group was significantly higher than control. The highest mean elastic modulus was detected in the SDF group (P<0.001). The use of SDF and GSE prior to the acid challenge improved mechanical properties. Microstructural investigation, using scanning electron microscope showed dentin structure protection against acid challenges with SDF treatment and collagen matrix stabilization with GSE treatment. However combined use of these agents was not beneficious.

"It's really no more difficult than putting on fluoride varnish": a qualitative exploration of dental professionals' views of silver diamine fluoride for the management of carious lesions in children

Background

Despite evidence that Silver Diamine Fluoride (SDF) can be effective in managing carious lesions in primary teeth, the use of SDF in the UK remains limited. This study explored dental professionals’ views and experiences of using SDF for managing carious lesions in children. In addition, it explored what they perceived to be the advantages, disadvantages, barriers and enablers to the use of SDF in practice.

Methods

Fifteen semi-structured face-to-face or over-the-phone interviews were conducted with 14 dental professionals from NHS Tayside and NHS Grampian in Scotland. Interviews were transcribed verbatim, coded and analysed using a thematic approach.

Results

Thirteen of 14 dental professionals interviewed were familiar with, or had some existing knowledge of, SDF. Four had used it to treat patients. The majority of participants thought that the main advantage of SDF was that it required minimal patient cooperation. SDF was also perceived as a simple, pain-free and non-invasive treatment approach that could help acclimatise children to the dental environment. However, SDF-induced black staining of arrested carious lesions was most commonly reported as the main disadvantage and greatest barrier to using it in practice. Participants believed that this discolouration would concern some parents who may fear that the black appearance may instigate bullying at school and that others may judge parents as neglecting their child’s oral health. Participants thought that education of clinicians about SDF use and information sheets for parents would enhance the uptake of SDF in dental practice. Participants believed that younger children might not be as bothered by the discolouration as older ones and they anticipated greater acceptance of SDF for posterior primary teeth by both parents and children.

Conclusion

Dental professionals were aware that SDF can be used for arresting carious lesions. They pointed out that the staining effect of carious lesions is a major disadvantage and had preconceived ideas that this could be a barrier for many parents. Participants considered the application process to be simple and non-invasive and requires a minimum level of child cooperation. Participants appreciated the potential of SDF in paediatric dentistry and suggested actions that could help overcome the barriers they highlighted.

Influence of Silver Diamine Fluoride Treatment on the Microtensile Bond Strength of Glass Ionomer Cement to Sound and Carious Dentin

CLINICAL RELEVANCE

This study provides valuable information about the influence of silver diamine fluoride (SDF) treatment on the microtensile bond strength of glass ionomer cement (GIC) to dentin.

SUMMARY

Objectives: To investigate the influence of silver diamine fluoride (SDF) treatment on the microtensile bond strength (mTBS) of glass ionomer cement (GIC) to sound and artificial carious dentin.Methods: Thirty dentin blocks prepared from 30 noncarious human molars were randomly allocated into either the sound (Gp1) or artificial carious dentin (Gp2) groups. A microbiological method was adopted to create artificial dentin caries lesions in Gp2 specimens. Each dentin block was sectioned into two halves perpendicularly, and each pair of block halves was randomly assigned to two subgroups to receive topical application of SDF (Gp1-SDF, Gp2-SDF) or water as control (Gp1-water, Gp2-water). An encapsulated GIC was bonded to the exposed dentin surfaces 14 days after the SDF/water application. After immersion for 7 days in artificial saliva, the GIC-dentin specimens were sectioned into beams for mTBS testing. Failure mode was examined after the mTBS test.Results: There was no significant difference in the mean mTBS values between the SDF and control subgroups (Gp1-SDF vs Gp1-water, 10.57±1.6 MPa vs 10.20±1.8 MPa; Gp2-SDF vs Gp2-water, 6.14±2.2 MPa vs 5.97±2.3 MPa; paired t-test, p>0.05). However, the mean mTBS value of the sound dentin group was significantly higher than that of the carious dentin group, irrespective of whether SDF was applied prior to GIC bonding (independent t-test, p<0.001). Proportionally more cohesive failures occurred in the sound dentin groups (Gp1-SDF, 48.4%; Gp1-water, 42.9%) compared with the carious dentin groups (Gp2-SDF, 15.6%; Gp2-water, 9.8%; p<0.05).Conclusions: SDF treatment had no significant influence on the mTBS of GIC to dentin. Compared with sound dentin, dentin with caries had lower mTBS to GIC.

Caries arrest and lesion appearance using two different silver fluoride therapies with and without potassium iodide: 6-month results

Objectives

to compare arrest rates and colour change in carious lesions in primary teeth using two different silver fluoride solutions with and without potassium iodide (KI).

Methods

The study was a four-armed, parallel-design randomised controlled trial and investigated four protocols for caries arrest at 6m. Children in Group 1 and Group 2 received Rivastar Silver Diammine Fluoride (SDF), and Children in Group 3 and Group 4 received an aqueous silver fluoride solution (AgF). Children in Group 2 and Group 4 received a two-step procedure where application of the AgF or SDF solution was followed by KI.

Results

At the six-month follow-up 446 (82.2%) children were re-examined. The arrest rate across the full sample was 51.4% and there were no significant differences in arrest rate by type of silver fluoride therapy. The lesion size, tooth type, surface type, presence of plaque on the carious lesion and caries increment all had an influence on caries arrest. Once clustering effects were accounted for, the use of KI was associated with a higher chance of arrest (OR 1.23; P-value 0.008) and a lower chance of the lesion darkening (OR 0.73; P-value <0.001).

Conclusions

The combination of AgF & KI was associated with the most favourable clinical outcomes in terms of caries arrest and lesion colour.

Clinical significance

The major draw-back of arrest of caries treatment with silver fluoride solutions is that it can create an appearance which may be aesthetically unacceptable. This study explores ways in which the base colour of lesions could be improved and as such provide the opportunity for better aesthetic outcomes for children afflicted with a severe burden of dental caries in their primary dentition, and in whom conventional treatment is not being provided.

Clinical efficacy and the antimicrobial potential of silver formulations in arresting dental caries: a systematic review

Background

The use of silver-formulation as microbicide to arrest dentinal caries is gaining popularity. The primary objective of the present appraisal was to systematically review the clinical (in vivo) applications and antimicrobial potential of silver-containing formulations in arresting dentinal caries. Our secondary aim was to sum up the available in vitro applications of silver-containing formulations against cariogenic microbes isolated from dentine lesions.

Methods

Ovid MEDLINE, EBSCO host, Web of Science, and Cochrane Library databases was searched between January 2009–May 2019.

Results

In vivo: We observed conflicting evidence of antimicrobial efficacy of SDF on a diverse array of microbial taxa present in carious dentine of primary and permanent teeth. Moreover, there is insufficient evidence on the application of AgNP-fluoride as an effective microbicidal against cariogens of dentine lesions.

In vitro: We found a good evidence of microbicidal efficacy of silver diamine fluoride (SDF) on selective cariogenic microbes in human dentine model. Additionally, a good evidence was noted of in vitro application of silver nanoparticles (AgNPs) as a useful microbicidal against S. mutans adhesion, growth and subsequent biofilm formation in human dentine models.

Conclusions

Taken together, in vitro evidence indicates the promising antimicrobial potential of silver-based formulations (SDF and nanosilver) against the predominant cariogenic flora, particularly from dentine lesions. Post-treatment clinical data of either the bactericidal and bacteriostatic effects of SDF or nanosilver are sparse. Furthermore, the current understanding of the specific size, concentration, antimicrobial mechanisms, and toxicological aspects of nano-silver compounds is inadequate to draw firm conclusions on their clinical utility.

Effect of silver diammine fluoride on micro-ecology of plaque from extensive caries of deciduous teeth - in vitro study

BACKGROUND

The mechanism of action of silver diammine fluoride (SDF) on plaque micro-ecology is seldom studied. This study investigated micro-ecological changes in dental plaque on extensive caries of deciduous teeth after topical SDF treatment.

METHODS

Deciduous teeth with extensive caries freshly removed from school children were collected in clinic. Unstimulated saliva collection and initial plaque sampling were done before tooth extraction, then each caries was topically treated with 38% SDF in vitro. After intervention, each tooth was stored respectively in artificial saliva at 37 °C. Repeated plaque collections were done at 24 h and 1 week post-intervention. Post-intervention micro-ecological changes including microbial diversity, microbial metabolism function as well as species correlations were analyzed and compared after pyrosequencing of the DNA from the plaque sample using Illumina MiSeq platform.

RESULTS

After SDF application, microbial diversity decreased (P > 0.05), although not statistically significant. Microbial community composition post-intervention was noticeably different from that of supragingival and pre-intervention plaque as well as saliva. At 1 week post-intervention, the relative content of Pseudomonas, Fusobacterium and Pseudoramibacter were higher than before, while most of the other bacteria were reduced, although the changes were not statistically significant (P > 0.05). The inter-microbial associations became more complex, much more positive associations among survived bacteria were observed than negative ones. COG function classification diagram showed carbohydrate transportation and metabolic functions in the plaque were significantly reduced at 24 h and 1 week post-intervention.

CONCLUSIONS

SDF has extensive antimicrobial effect on dental plaque, which may reduce carbohydrate metabolism in dental plaque and help promote new balance of the plaque flora.

A randomized clinical trial to arrest dentin caries in young children using silver diamine fluoride

OBJECTIVES

The study aimed to compare the effectiveness of 38% silver diamine fluoride (SDF) solution, and 5% sodium fluoride (NaF) varnish applied semiannually in arresting dentin caries in young children with high caries risk.

METHODS

Children aged 1-3 years who had at least one active dentin carious lesion were randomly allocated into 2 groups as follows: Group 1 = 38% SDF (Topamine), and Group 2 = 5% NaF varnish (Duraphat). Both agents were applied every 6 months onto the carious surface. Lesion activity was assessed by the visual-tactile examination. Baseline and follow-up examinations were conducted by the same examiner. The children's demographic background, oral health-related habits, and oral hygiene practices, as well as parental satisfaction with children's dental appearance were collected at baseline and the 12-month follow-up.

RESULTS

At baseline, 153 and 149 children were recruited in Group 1 and Group 2, respectively. The mean dmfs scores in Groups 1 and 2 were 8.89 and 9.79, respectively. After 12 months, 87.1% remained in the study. The caries arrest rate of Group 1 (35.7%) was significantly higher than that of Group 2 (20.9%) (p < 0.001). The results of the multilevel logistic regression analysis confirmed that the treatment in Group 1 was more effective in arresting dentin carious lesions than that of Group 2 (OR = 2.04; 95% CI, 1.41-2.96). The presence of plaque on caries lesions, tooth type, tooth surface type, frequency of milk feeding, snack taking, and family income influenced on caries activity. Regardless of the intervention groups, there were no differences in parental satisfaction with on the child's dental appearance before and after receiving the intervention.

CONCLUSION

Based on the 12-month results, 38% SDF is more effective than 5% NaF varnish in arresting dentin carious lesions in young children. SDF has no negative impact on parental satisfaction with the child's dental appearance.

CLINICAL SIGNIFICANCE

To control dentin carious lesions in young children with high caries risk, 38% SDF is more effective than 5% NaF varnish.

Synthesis and Characterization of Fluoridated Silver Nanoparticles and Their Potential as a Non-Staining Anti-Caries Agent

Objectives

The first objective of this study was to prepare sodium fluoride (NaF) solution with various concentrations of polyethylene glycol-coated silver nanoparticles (PEG-AgNPs). The second objective was to study the antibacterial activity against Streptococcus mutans and the tooth-staining effect of the solution.

Methods

PEG-AgNPs were prepared via the one-step chemical reduction of silver acetate with thiolated polyethylene glycol. The PEG-AgNPs were characterized with ultraviolet-visible spectrometry and transmission electron microscopy. The half maximal inhibitory concentration (IC50) for the PEG-AgNPs against Streptococcus mutans and human gingival fibroblasts (HGF-1) were determined. The staining effect on dentin and enamel for the 2.5% NaF solutions with PEG-AgNPs at 12,800, 6400, 1600, and 400 ppm was investigated using digital spectrophotometry. The IC50 of the fluoridated silver nanoparticles against Streptococcus mutans were measured.

Results

The PEG-AgNPs have an average diameter of 2.56±0.43 nm and showed excellent stability at high ionic strength (2.5% NaF) for 18 months. The IC50 of PEG-AgNPs against Streptococcus mutans was found to be 21.16±1.08 ppm silver, which was half of IC50 against HGF-1 cells (42.36±1.12 ppm), providing a working range to kill bacteria with no harm to human cells. The formulations with different concentrations of PEG-AgNPs showed no significant staining of teeth. Combining PEG-AgNPs with NaF significantly expanded the therapeutic window against Streptococcus mutans by reducing its IC50.

Conclusion

A biocompatible solution of NaF with PEG-AgNPs was developed. Because it has antibacterial activity against Streptococcus mutans and no tooth-staining effect, it can be used as an anti-caries agent.

Remineralising Dentine Caries Using Sodium Fluoride with Silver Nanoparticles: An In Vitro Study

Objective

To investigate the remineralizing and staining effects of sodium fluoride (NaF) solution with polyethylene glycol-coated silver nanoparticles (PEG-AgNPs) on artificial dentine caries.

Materials and Methods

Demineralized human dentine blocks were allocated to three groups. The blocks in group 1 underwent a topical application of a 12% silver diamine fluoride (SDF, 14,150 ppm fluoride) solution. The blocks in group 2 received a topical application of a 2.5% NaF (11,310 ppm fluoride) with PEG-AgNPs (400 ppm silver). The blocks in group 3 received deionized water. All blocks were subjected to pH cycling for 8 days. The surface morphology and cross-sectional features were investigated using scanning electron microscopy (SEM). The color parameters, crystal characteristics, lesion depth, and collagen degradation of the blocks were assessed using digital spectrophotometry, X-ray diffraction (XRD), micro-computed tomography, and spectrophotometry with a hydroxyproline assay, respectively.

Results

The SEM showed that dentine collagen was exposed in group 3 but not in groups 1 and 2. The mean lesion depths in groups 1 to 3 were 118±7 µm, 121±14 µm, and 339±20 µm, respectively (groups1,2<3; p<0.001). The data indicated that fluoridated PEG-AgNPs introduced no significant color effect on dentine, but SDF caused distinct discoloration. The XRD indicated that silver chloride was formed in group 1, and fluorapatite was detected in groups 1 and 2. The concentration of hydroxyproline liberated from collagen was significantly less in groups 1 and 2 than in group 3.

Conclusion

The use of NaF solution with PEG-AgNPs can remineralize artificial dentine caries and inhibit collagen degradation without causing significant tooth staining.

Topical Fluoride to Prevent Root Caries: Systematic Review with Network Meta-analysis

The aim of this systematic review and network meta-analysis was to summarize the direct and indirect clinical evidence on the effectiveness of professionally applied and self-applied topical fluorides in preventing dental root caries. Controlled clinical trials with any follow-up duration were included. MEDLINE, PubMed, Embase, Scopus, and Cochrane Library were searched. Two reviewers independently carried out the selection of studies, data extraction, risk-of-bias assessments, and assessment of the certainty in the evidence using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. Fixed effects model and frequentist approach were used in the network meta-analyses. Nine clinical trials involving 4,030 participants were included. Five professionally applied and 7 self-applied topical fluoride agents or combinations were included in the meta-analyses. Compared to control group, 38% silver diamine fluoride solution, 5% sodium fluoride varnish, and 1.2% acidulated phosphate fluoride reduced root caries increment after 2 y (ranging from 0.59 to 0.85 mean decayed or filled root [DF-root]). Fluoride mouth rinse and fluoride toothpaste, used alone or in combination, reduced root caries increment after 1 y (ranging from 0.29 to 1.90 mean DF-root). Among the professionally applied topical fluorides reviewed, an annually applied 38% silver diamine fluoride (SDF) solution combined with oral health education is most likely to be the most effective in preventing dental root caries. Among the reviewed self-applied topical fluoride methods, daily use of a 0.2% sodium fluoride (NaF) mouth rinse is most likely to be the most effective, followed by 1100 ppm to 1500 ppm fluoride toothpaste plus 0.05% NaF mouth rinse, and 1100 ppm to 1500 ppm fluoride toothpaste.

Cavity treatment in primary molars and malocclusion: quasi-randomised clinical trial

Background

An innovative caries treatment protocol for primary teeth, termed Ultra-Conservative Treatment (UCT), restores small cavities through the Atraumatic Restorative Treatment (ART) protocol and cleans medium to large open cavities with toothbrush and fluoride toothpaste. However, UCT-treated primary molars were found to exfoliate earlier than amalgam (CRT) and ART-restored cavities, which may lead to unacceptable loss of space for normal eruption of permanent successors. The null-hypothesis tested was that there is no difference between the three treatment protocols and the intra-arch distances, and index of orthodontic treatment need (IOTN) after 4 years.

Methods

Dental casts were taken at baseline (T0) and four (T4) years. The space of the premolars (D + E space), arch perimeter, anterior and total arch depth were measured using a morphometric computer programme. The presence and level of malocclusion were assessed according to the IOTN index. Dependent variables were all intra-arch distances and the IOTN while the independent variable was treatment protocol (CRT, ART and UCT). Data were analysed using linear and logistic regression.

Results

The sample consisted of 867 pairs of casts of 272 initial 6–7-year-olds. No difference was observed between the UCT protocol and the two restorative protocols for the intra-arch variables in both maxilla and mandible over the 4 year period. There was no difference between the UCT and the CRT and ART protocols regarding the occurrence of orthodontic treatment need (malocclusion). In conclusion, the UCT treatment protocol does not differ significantly from the traditional amalgam (CRT) and ART restorative protocols with respect to intra-arch distances and malocclusion. The earlier exfoliation of UCT-treated primary molars does not lead to a worsening of the eruption pattern of permanent successors.

Effect of silver diamine fluoride solution application on the bond strength of dentine to adhesives and to glass ionomer cements: a systematic review

Background

Silver diamine fluoride (SDF) solution gains increasing popularity in arresting dentine caries in clinical practice. The aim of this systematic review was to summarize the findings from laboratory studies on the influence of SDF application on the bond strength of dentine to various adhesives and to glass ionomer cements (GICs).

Methods

Two independent reviewers conducted a literature search in the databases Medline, Ovid, PubMed and Web of Science until 15th August 2019 using the search keywords [‘bond strength’] AND [‘silver diamine fluoride’ OR ‘silver diammine fluoride’ OR ‘SDF’ OR ‘silver fluoride’ OR ‘diamine silver fluoride’]. Articles investigating the effect of SDF application on the bond strength of dentine to various adhesives and to GICs were included in this review. Information on how SDF application influenced the bond strength was extracted from the included articles. Besides, related information, e.g. test method of bond strength, concentration and brand of SDF, type of adhesive system and GIC, testing dental substrate, protocol of specimen preparation, and failure mode was also reviewed.

Results

A total of 13 articles were included in this review, with 8 and 6 studies investigating the effect of SDF application on the bond strength of dentine to various adhesives and to GICs, respectively. Sound dentine as well as demineralized dentine created by chemical methods, e.g. immersing in a demineralizing solution, was commonly adopted as the testing dental substrate. The microtensile bond strength (mTBS) test was the predominant method employed. However, the bond strength values had large variations among studies, ranging from <10 to 162 Mpa. Regarding the bond strength to different adhesives, 4 studies indicated that SDF application followed by rinsing with water had no significant influence. However, another 4 studies reported reduced bond strength after SDF application. Regarding the bond strength to GICs, 4 studies concluded that SDF application had no adverse impact on the bond strength.

Conclusions

No solid conclusion can be drawn on the effect of SDF application on the bond strength of dentine to adhesives and to GICs due to the high degree of variation of the included studies.

Use of the consolidated framework for implementation research to assess determinants of silver diamine fluoride implementation in safety net dental clinics

OBJECTIVES

In the United States, silver diamine fluoride (SDF) is a relatively new, quick, and low-cost method for arresting dental caries. This study's purpose was to identify determinants of the implementation of an SDF protocol for pediatric patients in three safety net clinics to inform future efforts to implement the protocol.

METHODS

We familiarized dental personnel with the SDF protocol through on-site education and feedback sessions. Two months after the educational sessions, we conducted focus groups with a total of eight dentists and 21 staff across three North Carolina safety net dental clinics: a private nonprofit healthcare network, a community health center, and a county health department. We used the Consolidated Framework for Implementation Research (CFIR) to understand determinants of implementation of the protocol.

RESULTS

Determinants of SDF protocol implementation included SDF protocol characteristics (e.g., source of protocol and its ease of use and adaptability, relative advantage compared to alternatives, low cost), characteristics of the outer setting or the dental clinic's environment (e.g., patient needs), inner setting or dental clinics' characteristics (e.g., culture of safety net clinic, leadership engagement), characteristics of dental personnel (e.g., concerns were alleviated by the training and having the protocol), and process characteristics (e.g., training and technical assistance from a reliable source). Overall, implementation was less successful in clinics with less leadership engagement and turnover of dental personnel who did not receive the training.

CONCLUSIONS

The determinants of SDF protocol implementation identified in this study will be useful to guide future efforts to implement the SDF protocol.

Effect of Silver Diamine Fluoride Treatment on Microbial Profiles of Plaque Biofilms from Root/Cervical Caries Lesions

Purpose: To assess the effect of silver diamine fluoride (SDF) on microbial profiles present in plaque from root/cervical carious lesions, and its association with caries lesion arrest. Materials and Methods: Twenty patients with at least one soft cavitated root/cervical carious lesion were included. One lesion/patient was randomly selected and treated with 38% SDF. Supragingival plaque samples were harvested at preintervention and 1 month postintervention. Using an MiSeq platform, 16S rDNA sequencing of the V3-V4 regions was used to determine bacterial profiles. Clinical evaluation of lesion hardness was used to evaluate arrest. t tests, principal component analysis (PCA), multidimensional scaling (MDS), and generalized linear models (GLMs) tests were used for statistical comparisons. Results: From a total of 40 plaque samples, 468 probe targets were observed. Although 60% of lesions became hard postintervention, PCA and MDS tests showed no distinct pre- and postintervention groups. In addition, pre- and postintervention differences in diversity (Shannon index) of microbial profiles between patients with and without lesion arrest were not statistically different. A likelihood ratio test for pre- versus postintervention differences within patients, i.e., adjusting for differences between patients using negative binomial GLMs, showed 17 bacterial taxa with significant differences (FDR <0.05). Conclusion: Although 60% of lesions hardened after SDF treatment, this was not directly due to either overall statistically significant differences in microbial profiles or differences in microbial diversity. Nevertheless, there was a trend with some acid-producing species in that their relative abundance was reduced postintervention. The negative binomial GLMs showed 17 bacterial taxa that were significantly different after SDF treatment.

Aesthetic perception, acceptability and satisfaction in the treatment of caries lesions with silver diamine fluoride: A scoping review

BACKGROUND

Silver diamine fluoride (SDF) causes dental black staining after its application.

AIM

Evaluate the aesthetic perception, acceptability, and/or satisfaction of patients, parents, and professionals to the treatment of caries lesions with SDF through a scoping review.

DESIGN

A search was performed in seven databases and two key journals with no language or date restrictions. Studies that evaluated the aesthetic perception, satisfaction, and/or acceptability of patients, parents, and professionals to the treatment of carious lesions with SDF were considered eligible.

RESULTS

From a total of 1177 articles, 10 studies were full text assessed for eligibility, with nine included in this scoping review. In general, the studies varied by population, study design, and methodologic evaluation. The type of tooth (anterior or posterior), family income, parental schooling, ethnicity, and need for advanced behaviour control methods were factors that influenced the results. The acceptability level increased as the child required more advanced methods of behaviour guidance. In general, the pigmentation caused by SDF did not interfere with the parents' acceptability of the treatment; however, professionals believe that this could have influence. Regarding satisfaction, pigmentation did not influence parental satisfaction.

CONCLUSION

Parents were satisfied with and found SDF acceptable, whereas professionals did not.

Effects of silver diamine fluoride/potassium iodide on artificial root caries lesions with adjunctive application of proanthocyanidin

Treatment of carious root surfaces remains challenging due to the complex pathological processes and difficulty in restoring the original structure of root dentine. Current treatments targeting the de-/re-mineralisation processes are not entirely satisfactory in terms of the protection of the dentinal organic matrix and the highly organised structure of dentine. In this in vitro study, a cross-linking agent - proanthocyanidin (PA) was used in conjunction with a fluoride-based treatment - silver diamine fluoride/potassium iodide (SDF/KI) to putatively stabilise the organic dentinal framework as well as strengthen the collagen-mineral phase interaction. The effectiveness of this strategy was evaluated 24 h after application in terms of the distribution of ion uptake and microstructure of dentine after treatment as well as analysis of the nano-mechanical properties using a dynamic behaviour model. Results showed that individual use of SDF/KI significantly improved the surface microhardness and integrated mineral density (Z) up to 60 µm depth and the recovery of creep behaviour of demineralised dentine in the surface area compared to that treated with deionised distilled water (DDW). The combined treatment of PA and SDF/KI achieved a more homogenous mineral distribution throughout the lesions than SDF/KI alone; a more significant incremental increase in surface microhardness and Z was observed. Specifically, a superior effect on the subsurface area occurred with PA + SDF/KI, with significant improvements in microhardness, elastic modulus and recovery of creep behaviour of the demineralised dentine. Application of SDF/KI induced small discrete crystal formation distributed over the dentine surface and PA contributed to the formation of slit-shaped orifices of the dentinal tubules that were partially occluded. STATEMENT OF SIGNIFICANCE: Demographic transitions and improved oral health behaviour have resulted in increased tooth retention in elderly people. As a consequence, the risk of root dentine caries is increasing due to the age-associated gingival recession and the related frequent exposure of cervical root dentine. Root caries is difficult to repair because of the complex aetiology and dentine structure. The recovery of dentine quality depends not only on reincorporation of minerals but also an intact dentinal organic matrix and the organic-inorganic interfacial structure, which contribute to the biomechanics of dentine. With the capability of dentine modification, cross-linking agents were applied with a fluoride regimen, which improved its treatment efficacy of root caries regarding the distribution of ion uptake and recovery of dentine biomechanics.

Assessment of the Silver Penetration and Distribution in Carious Lesions of Deciduous Teeth Treated with Silver Diamine Fluoride

The aim of this study was to determine the effects of 38% silver diamine fluoride (SDF) on carious lesions of human deciduous teeth. Ten extracted deciduous incisors with caries were collected and treated with SDF. After the treatment, the teeth were sectioned through the center of the carious lesion. The extent of sliver precipitation was examined using quantitative backscattered electron scanning electron microscopy (qBSE-SEM), energy-dispersive X-ray spectroscopy (EDX), and micro-computed tomography (micro-CT). The qBSE-SEM images revealed that the silver particles could penetrate through the pellicle complex, along with the rod sheaths into the demineralized enamel rods and the dentinal tubules, and form silver-enriched barriers surrounding the carious lesions at depths up to 2,490.2 μm (mean 744.7 ± 448.7 μm) within the dentinal tubules of the carious lesions, but less likely in the sound enamel. The EDX spectrum analysis revealed that carbon, oxygen, phosphorus, chlorine, silver, and calcium were the main elements detected in the lesions treated with SDF. Additionally, sodium, magnesium, aluminum, silicon, zinc, sulfur, and fluorine were detected as the minor elements within the SDF precipitation "zone." The micro-CT analysis further showed that in the deep cavitated lesions, the silver precipitation could be observed in the pulp chamber. These findings provide new evidence defining the SDF mode of action for arresting caries and suggest that the application of a highly concentrated SDF solution on deciduous teeth should be used with caution for various carious lesions.

Silver diamine fluoride versus sodium fluoride for arresting dentine caries in children: a systematic review and meta-analysis

Dental caries can compromise quality of life and is associated with demineralization of tooth structure by organic acids produced by microorganisms. This study systematically reviewed the dentine caries arrest capabilities of silver diamine fluoride (SDF) and sodium fluoride (NaF). A comprehensive search strategy was developed to identify the relevant publications in electronic databases and hand searched journals and reviews (to March 2018). By applying strict inclusion and exclusion criteria, only six papers (two randomized controlled trials, two follow-up articles and two secondary statistical analysis studies) were considered for full text qualitative and quantitative assessment. The included studies were critically appraised and statistically evaluated. Only four articles were considered for meta-analysis, as the other two were secondary analyses of included studies. When comparing the caries arrest lesions of SDF and NaF, SDF was found to be statistically more effective in dentine caries arrest of primary teeth during the 18 and 30 month clinical examinations. The weighted total effect size of the differences between SDF and NaF regarding arrested caries surfaces was calculated and showed nearly double the effectiveness of SDF to NaF at 30 months. Therefore, SDF is a more effective caries management reagent than NaF. Further clinical research is needed to consolidate the findings of this systematic review.

Silver and fluoride content and short-term stability of 38% silver diamine fluoride

BACKGROUND

As silver diamine fluoride (SDF) gains popularity for caries arrest, the authors aimed to investigate the content of fluoride and silver in 38% SDF produced for the US market and its short-term stability.

METHODS

Five samples of 38% SDF were evaluated when the bottle was first opened, and at 7 and 28 days. Fluoride concentrations were determined with a fluoride ion-selective electrode, and silver concentrations were determined with a simultaneous inductively coupled plasma mass spectrometer. pH was measured with a pH probe. Weight and volume of individual drops were measured.

RESULTS

At day 0, 40% of individual measured values were above the expected fluoride concentration, and at day 28, 93% were above the expected fluoride concentration (P = .005). At day 0, 19% of individual measured values were below the lowest expected silver concentration, and at day 28, 93% were below (P < .001). Acidity (pH 10) was consistent over the 3 periods. Mean (standard deviation) weight of a drop was 40 (4.0) milligrams, and mean (standard deviation) volume was 32.55 (1.89) microliters, 30% more than the reported value of 25 μL.

CONCLUSION

Over 28 days, the product pH is stable, whereas the fluoride content tends to increase and the silver content tends to decrease. Drops were larger than expected when dispensed from the bottle.

PRACTICAL IMPLICATIONS

Drops are larger than expected, so each delivers higher than expected quantities of silver and fluoride. Clinicians should exercise caution when using this product on young children, replace the cap immediately, and use as soon as dispensed.

Sodium fluoride and silver diamine fluoride-coated tooth surfaces inhibit bacterial acid production at the bacteria/tooth interface

OBJECTIVES

This study aimed to evaluate whether coating tooth surfaces with sodium fluoride (NaF) or silver diamine fluoride (SDF) inhibits bacteria-induced pH reductions at the bacteria/tooth interface.

METHODS

Specimens of coronal enamel (CE) or root dentin (RD) were prepared. The surfaces of the specimens were treated with 2% NaF or 38% SDF solution. Some specimens were aged for 1 week after being treated. A tooth specimen was fixed to the bottom of the well of the experimental apparatus. A miniature pH electrode was placed on the specimen and the well was filled with Streptococcus mutans (SM) cells. The pH was monitored after the addition of 0.5% glucose. SM cells were recovered from the wells, and the amounts of lactate, calcium, fluoride, and silver were measured.

RESULTS

The fluoride-treated tooth specimens exhibited significantly higher pH values than the untreated controls, irrespective of the tooth substrate at 120 min (CE: NaF 4.62 ± 0.06 vs 4.34 ± 0.10 and SDF 5.23 ± 0.29 vs 4.44 ± 0.16, RD: NaF 5.10 ± 0.11 vs 4.54 ± 0.33 and SDF 6.65 ± 0.47 vs 4.64 ± 0.39). The SDF-coated RD specimens released the greatest amounts of fluoride (103.3 ± 48.1 nmol/well) and silver (70.4 ± 36.9 nmol/well), while they exhibited significantly lower lactate production and decalcification (calcium release) than the control samples (lactate: 4.0 ± 0.7 vs 7.4 ± 0.3 mmol/l, calcium: 2.2 ± 0.4 vs 3.7 ± 0.5 μg/ml). This antimicrobial effect was weakened by 1 week's aging, while the acid resistance of the fluoride-treated surfaces seemed to increase with aging.

CONCLUSIONS

Fluoride-treated tooth surfaces inhibit bacterial acid production at the bacteria/tooth interface. The SDF-coated RD had the strongest inhibitory effect.

CLINICAL SIGNIFICANCE

Coating RD with SDF could help to prevent root caries.

Remineralisation of enamel with silver diamine fluoride and sodium fluoride

OBJECTIVE

To evaluate the remineralising effect of the adjunctive application of 38% silver diamine fluoride (SDF) solution and 5% sodium fluoride (NaF) varnish on artificial enamel caries lesions.

METHODS

Forty-eight demineralised enamel specimens were allocated into four groups. Group 1 received 38% SDF and 5% NaF; Group 2 received 38% SDF; Group 3 received 5% NaF; and Group 4 received deionized water. After pH cycling, the surface morphology and fluoride content of the specimens were studied via scanning electron microscopy (SEM)/energy dispersive spectroscopy (EDS). The lesion depth and crystal characteristics were assessed using micro-computed tomography and X-ray diffraction (XRD) respectively. The crystallization reaction was performed by incubating hydroxyapatite powder with NaF or SDF for 48h. The precipitates were studied via transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS).

RESULTS

SEM demonstrated the destruction of the enamel surface in Group 4. EDS revealed that the mean fluoride weight percentage of Groups 1-4 were 1.28±0.15, 1.33±0.19, 1.03±0.09 and 0.87±0.04 respectively. The mean lesion depths of Groups 1-4 were 129±14μm, 131±16μm, 153±10μm and 181±21μm respectively. The addition of NaF to SDF did not reduce the lesion depths (p=0.779). XRD revealed that silver chloride formed as a main product in Groups 1 and 2. Meanwhile, TEM analysis indicated that silver nanoparticles were incorporated into hydroxyapatite crystal in SDF-treated hydroxyapatite. XPS spectra suggested that the chemical state of the silver was metallic.

SIGNIFICANCE

The adjunctive application of SDF and NaF varnish had a similar remineralising effect to that of SDF on enamel caries.