Caries-arresting effects of silver diamine fluoride and sodium fluoride on dentine caries lesions

Using sequential applications of a novel silver diamine fluoride gel and sodium fluoride varnish to arrest severe early childhood caries lesions: A clinical trial with single group assignment

BACKGROUND

Silver diamine fluoride (SDF) gel was developed to overcome the clinical limitations of liquids with children. The authors conducted a clinical trial to determine caries lesion arrest in primary teeth at 1-year follow-up when 38% SDF gel and 2.5% sodium fluoride varnish were applied sequentially at the same appointment. Parent satisfaction was assessed.

METHODS

The study design was an open-label prospective, clinical trial with single group assignment. Participants were 237 children aged 3 through 4 years at enrollment and from 5 centros educativos iniciales (preschools). Eligible children had 1 or more d3 (cavitation into dentin) active caries lesions. Teeth with active caries lesions (cavitation confined to enamel [d2] or d3) were treated by applying 1 or 2 drops of viscous 38% SDF gel (Advantage Silver Dental Arrest Gel, Elevate Oral Care, LLC) dabbing the excess with cotton. Treated teeth were covered with 2.5% sodium fluoride varnish (Fluorimax, Elevate Oral Care, LLC) to mask the taste. Treatment was repeated at 5 months postexamination. The primary outcome was caries lesion (d2-d3) arrest at 1 year.

RESULTS

Two hundred nineteen children were available at the 1-year follow-up. There was a median of 21 (interquartile range [IQR], 13-34) active carious surfaces (d2-d3) at baseline. Median arrested carious surfaces was 92.6% (IQR, 81.1%-100.0%; 95% CI, 86.8% to 95.2%). When parents were asked whether they were bothered by the color change of teeth, the median response on a 10-point scale in which 1 equaled not bothered at all and 10 equaled very bothered was 1.0 (IQR, 1.0-2.0).

CONCLUSIONS

Two applications of 38% SDF gel and 2.5% sodium fluoride varnish arrested greater than 90% of carious surfaces at 1 year and with high levels of parental satisfaction.

PRACTICAL IMPLICATIONS

Combined treatment was highly efficacious in a population with many caries lesions. This clinical trial was registered at ClinicalTrials.gov. The registration number is NCT05395065.

Chemical kinetics of silver diammine fluoride in demineralization and remineralization solutions-an in vitro study

Introduction

Silver Diammine Fluoride (SDF) is a clinical minimal intervention to manage dentin caries. Its chemistry in demineralization conditions has been investigated widely, but far less in remineralization conditions. The aim was to investigate and compare the chemical reactions when SDF is added to remineralization and demineralization solutions.

Methods

0.01 ml SDF (Riva Star) was added to deionized water (DW); demineralization (DS = pH4) and remineralization (RS = pH7.0) solutions. The time sequence of concentrations of NH4+, F-, and Ag+ were measured using ion selective electrodes (ISEs) every 2 min. The pH was also measured. Precipitates were characterized using x-ray Diffraction (XRD) and, 31P and 19F nuclear magnetic resonance spectroscopy (NMR).

Results

The concentrations of NH4+ and Ag+ showed decreasing trends in DW (-0.12 and -0.08 mM/h respectively), and in DS (-1.06 and -0.5 mM/h respectively); with corresponding increase in F- concentration (0.04 and 0.7 mM/h respectively). However, in RS, NH4+ concentration showed little change (0.001 mM/h), and Ag+ and F- concentrations were negligible. XRD results showed that precipitates (in RS only) contained AgCl, and metallic Ag. NMR showed that fluorapatite/carbonated fluorapatite (FAP/CFAP) were formed. The pH increased after SDF addition in all three solutions.

Discussion

SDF dissolved to release NH4+, F- and Ag + . In DW and DS, NH4+ combined with Ag+ to form diamminesilver, causing an increase of F- and pH. In RS, F- reacted with Ca2+ and (PO)43- to form FAP/CFAP, and Ag+ reacted with Cl- to form AgCl/Ag. These suggests why SDF is effective in managing dentin caries.

The effect of silver nanoparticles in addition to sodium fluoride on remineralization of artificial root dentin caries

BACKGROUND

Silver nanoparticle was developed to overcome the drawback of silver diamine fluoride. However, evidence is limited, especially in root caries. The aim of this study was to evaluate the remineralization effect of silver nanoparticles on root caries.

MATERIALS AND METHODS

Fifty-five root human dentin slices size 5 × 5 mm2 from patients aged over 60 years old were immersed in demineralized solution to create artificial caries. Specimens were allocated into five groups according to the remineralizing agents: silver diamine fluoride (SDF), silver nanoparticles solution (AgNPs), silver nanoparticle solution followed by sodium fluoride varnish (AgNPs+NaF), sodium fluoride varnish (NaF), and tap water. After 8 days of pH-cycling challenge, the microhardness test, lesion depth evaluation, dentin surface morphology, and elemental analysis were performed. Data was analysed using F-test One-way ANOVA followed by Tukey's post hoc test and paired T-test.

RESULTS

All test groups demonstrated a significantly higher microhardness value and lower lesion depth compared with the control group. AgNPs+NaF and NaF-treated groups showed lower efficacy than SDF. Crystal precipitation was presented in all groups composed of silver.

CONCLUSION

Addition of fluoride varnish did not benefit for silver nanoparticles in preventing further demineralization. SDF provides the highest effectiveness in elderly root carious dentin.

The Evolving Microbiome of Dental Caries

Dental caries is a significant oral and public health problem worldwide, especially in low-income populations. The risk of dental caries increases with frequent intake of dietary carbohydrates, including sugars, leading to increased acidity and disruption of the symbiotic diverse and complex microbial community of health. Excess acid production leads to a dysbiotic shift in the bacterial biofilm composition, demineralization of tooth structure, and cavities. Highly acidic and acid-tolerant species associated with caries include Streptococcus mutans, Lactobacillus, Actinomyces, Bifidobacterium, and Scardovia species. The differences in microbiotas depend on tooth site, extent of carious lesions, and rate of disease progression. Metagenomics and metatranscriptomics not only reveal the structure and genetic potential of the caries-associated microbiome, but, more importantly, capture the genetic makeup of the metabolically active microbiome in lesion sites. Due to its multifactorial nature, caries has been difficult to prevent. The use of topical fluoride has had a significant impact on reducing caries in clinical settings, but the approach is costly; the results are less sustainable for high-caries-risk individuals, especially children. Developing treatment regimens that specifically target S. mutans and other acidogenic bacteria, such as using nanoparticles, show promise in altering the cariogenic microbiome, thereby combatting the disease.

Teaching of silver diamine fluoride for the management of dental caries and hypersensitivity - situation in the Southeast Asia dental schools

BACKGROUND

Using silver diamine fluoride (SDF) for caries management has raised dentists' interests in Southeast Asia (SEA). However, information about the teaching of SDF in dental schools in SEA is limited. Therefore, this survey aimed to describe the extent to which SDF had been introduced into the education of undergraduate students in the dental schools in SEA.

METHODS

An online questionnaire survey was conducted on the duration, method, contents, and barriers regarding the teaching of SDF. Teachers in charge of undergraduate program in pediatric dentistry and those in community dentistry in all the 90 dental schools in SEA were approached and we required each department to reply once only. Descriptive statistics and Chi-square test were used to describe and assess the differences between the two departments in the teaching of SDF.

RESULTS

A total of 81 responses from the departments of 49 schools were received, giving a school-level response rate of 54% (49/90). SDF was taught in the undergraduate program in 86% (42/49) of the respondent schools, and 50% (21/42) of these schools had included SDF in the teaching for five or more years. Almost all (98%) of the departments taught SDF through lectures. Furthermore, 55% of them adopted SDF in clinical practice. Regarding the teaching content, the use of SDF for arresting cavitated caries lesion was the most commonly covered (82-97%), followed by for arresting early noncavitated lesions (69-82%), for preventing new caries development (66-79%) and for treating dental hypersensitivity (77%). There were variations in the post-treatment instruction taught. For the departments not teaching SDF, the most common reason (10/19, 53%) was that SDF was not available.

CONCLUSION

SDF is covered in the undergraduate program in most of the dental schools in SEA. The use of SDF to arrest cavitated caries lesions in primary teeth is usually taught. However, other applications of SDF, such as for prevention of caries and treatment of dental hypersensitivity, are less commonly mentioned in the teaching.

Effect of silver diamine fluoride upon the microbial community of carious lesions: A scoping review

OBJECTIVES

To explore the effects of silver diamine fluoride (SDF) on the microbial community of carious lesions.

DATA

Original studies evaluating the effect of SDF treatment on the microbial community of human carious lesions were included.

SOURCES

A systematic search of English-language publications was performed in PubMed, EMBASE, Scopus, and Web of Science. Gray literature was searched in ClinicalTrials.gov and Google Scholar.

STUDY SELECTION/RESULTS

This review included seven publications reporting the effects of SDF on microbial community of dental plaque or carious dentin, including the microbial biodiversity, relative abundance of microbial taxa, and predicted functional pathways of the microbial community. The studies on microbial community of dental plaque reported that SDF did not have a significant effect on both the within-community species diversity (alpha-diversity) and inter-community microbial compositional dissimilarity (beta-diversity) of the plaque microbial communities. However, SDF changed the relative abundance of 29 bacterial species of plaque community, inhibited carbohydrate transportation and interfered with the metabolic functions of the plaque microbial community. A study on the microbial community in dentin carious lesions reported that SDF affected its beta-diversity and changed the relative abundance of 14 bacterial species.

CONCLUSION

SDF showed no significant effects on the biodiversity of the plaque microbial community but changed the beta-diversity of the carious dentin microbial community. SDF could change the relative abundance of certain bacterial species in the dental plaque and the carious dentin. SDF could also affect the predicted functional pathways of the microbial community.

CLINICAL SIGNIFICANCE

This review provided comprehensive evidence on the potential effect of SDF treatment on the microbial community of carious lesions.

Enhanced effectiveness of silver diamine fluoride application with light curing on natural dentin carious lesions: an in vitro study

This study aimed to compare the mean mineral density difference (mMDD) and surface morphology of 10- and 60-s silver diamine fluoride (SDF)-applied dentin carious lesions and to study the effect of an additional 20-s light curing (LC) on SDF-treated teeth. Forty primary molar blocks with natural dentin carious lesions were measured for baseline lesion depth and mineral density using Image-Pro Plus software. The samples were randomly distributed into 4 groups; 38% SDF applied for 1) 10-s (10SDF), 2) 60-s (60SDF), 3) 10-s + LC (10SDF + LC), 4) 60-s + LC (60SDF + LC) and an additional control group to assess the outcome of pH-cycling only. Then all the groups underwent a 7-d bacterial pH-cycling. The dentin carious lesions' mMDD was determined by digital subtraction radiographic analysis. The surface morphology and elemental profile were assessed by scanning electron microscopy and energy-dispersive X-ray spectroscopy. The mMDD of the dentin lesions was analyzed using two-way ANOVA, generalized linear models analysis. Light curing was the only factor that affected the mMDD (p = 0.007). The mMDD in the 10SDF + LC and 60SDF + LC groups were significantly higher than those without light curing (p = 0.041 and 0.041, respectively). The 60SDF + LC group demonstrated a significantly higher mMDD than the 10SDF group (p = 0.010), while that in the 10SDF + LC group was similar to the 60SDF group (p = 1.00). Scanning electron microscopy revealed denser mineral content layers, which were likely silver and chloride, in the 10SDF + LC and 60SDF + LC groups than in the 10SDF and 60SDF groups, respectively. In conclusion, shortened application time with light curing enhanced SDF remineralization similarly to the conventional method.

Effect of silver nanoparticles associated with fluoride on the progression of root dentin caries in vitro

OBJECTIVES

To assess the anti-proteolytic effect and potential to inhibit dentin root caries progression of a silver nanoparticle and fluoride solution (CNanoF) in comparison to silver diamine fluoride (SDF).

METHODS

48 specimens of root dentin artificial caries lesion were treated with 38% SDF, CNanoF, CNano or F (n = 6 per group). Ph cycling with demineralization and remineralization solutions simulated caries lesion progression. In addition, specimens were incubated with or without bacterial collagenase in the remineralization solution to induce dentin proteolytic degradation. Dentin degradation was assessed by weight loss rate and hydroxyproline (Hyp) release. Changes in cross-sectional microhardness, and lesion permeability and collagen integrity as determined by confocal laser scanning microscopy indicated potential for further demineralization inhibition. The effect of the solutions on the activity of metalloproteinases (MMP) -2 and -9 was also investigated. Statistical analysis consisted of ANOVA, Kruskal-Wallis, and linear mixed models with post-hoc pairwise Tukey, Dunn, and t-tests (α = 0.05).

RESULTS

Treatment with SDF resulted in lower weight loss rate than did other solutions, but all groups showed similar Hyp release (p = 0.183). SDF resulted in greater microhardness at superficial layers of the caries lesions (p<0.05), while there were no differences among CNanoF, CNano, and F. Lesion permeability was similar among all groups after pH cycling (p>0.05), with or without the use of collagenase (p = 0.58). No statistically significant difference was noted among solutions regarding collagen integrity after pH cycling; however, SDF-treated dentin had a significant decrease in collagen integrity when collagenase was used (p = 0.003). Interestingly, only SDF was able to completely inactivate MMP-2 and -9.

CONCLUSIONS

CNanoF and SDF both potentially prevent dentin degradation during caries lesion progression in vitro; however, SDF was more effective at inhibiting further tissue demineralization.

Effectiveness of Silver Diamine Fluoride and Sodium Fluoride Varnish in Preventing New Carious Lesion in Preschoolers: A Randomized Clinical Trial

Introduction

Dental caries is a site-specific, multifactorial chronic disease affected globally. The prevalence of dental caries is strongly associated with social and economic disadvantage, and also the susceptibility of children to dental caries. Dental caries prevention can be achieved with topical fluoride agents. Topical fluoride promotes the remineralization of early carious lesions and reduces the demineralization of healthy enamel.

Aim

The aim of this randomized clinical trial was to compare the effectiveness of silver diamine fluoride (SDF) and sodium fluoride varnish (FV) in preventing new carious lesions in preschoolers.

Materials and methods

This randomized clinical trial was conducted on 285 children aged 3-6 years. Children were randomly allocated into three groups namely, group I-deionized distilled water (DIW), group II-sodium FV, and group III-SDF. The biannual application was performed at an interval of 6 months. New carious lesions were recorded using defs and International Caries Detection and Assessment System (ICDAS II) under LED magnifying loupes. Descriptive and inferential statistics were applied and tabulated using Statistical Package for the Social Sciences (SPSS) 23.0 software.

Result

There was a significant difference seen in the mean values of group III (SDF) when compared with group II (FV) and also between group III (SDF) and group I (DIW) when defs index was used. The mean score of ICDAS II after 12 months in group I (DIW) was -1.171, group II (FV) was -0.690, and group III (SDF) was -0.374.

Conclusion

silver diamine fluoride (SDF) was found to be most effective in preventing dental caries and also it appears to be the most cost-saving fluoride therapy.

How to cite this article

Jain A, Deshpande AN, Shah YS, et al. Effectiveness of Silver Diamine Fluoride and Sodium Fluoride Varnish in Preventing New Carious Lesion in Preschoolers: A Randomized Clinical Trial. Int J Clin Pediatr Dent 2023;16(1):1-8.

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.

Solid-state NMR spectroscopy measurement of fluoride reaction by bovine enamel and dentin treated with silver diammine fluoride

OBJECTIVES

The aim of this study was to investigate the formation of fluoride compounds in bovine enamel and dentin treated with silver diammine fluoride (SDF) using ¹⁹F and ³¹P solid-state magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy.

METHODS

Enamel and dentin powder, obtained from bovine teeth, were treated with 38% SDF for four minutes and then washed thoroughly with Milli-Q water. The dehydrated SDF-treated samples were then examined. ¹⁹F solid-state MAS NMR spectra were acquired and ¹H-³¹P cross-polarization (CP) experiments were performed on SDF-treated enamel and dentin powder. The surfaces of SDF-treated enamel and dentin blocks were observed by Scanning Electron Microscope (SEM).

RESULTS

¹⁹F MAS NMR detected a more pronounced signal intensity for the dentin sample than the enamel, indicating an increased reactivity of SDF for dentin, compared with enamel. ¹⁹F NMR spectra for the SDF-treated samples showed fluorhydroxyapatite (FHAp), and other fluoride compounds such as CaF₂ and the fluoride-substituted carbonate. The ¹H-³¹P CP intensities of prominent peaks were lower for the SDF-treated samples than the non-treated sample, indicating that the F^- ion replaced the OH^- ion in the lattice tunnel. SEM observations on the SDF-treated samples showed pronounced multiple precipitation and particles in dentin compared with enamel.

SIGNIFICANCE

The solid-state MAS NMR revealed the reaction of fluoride on enamel and dentin and the identification of fluoride compounds. In particular, the formation of FHAp indicates that SDF is effective in reducing the risk of tooth decay.

Potent Antibacterial and Antibiofilm Activities of a Synthetic Remineralizing Preparation of Nano-Hydroxyapatite Against Cariogenic Streptococcus mutans Using an Ex-vivo Animal Model

Aim

The aim to this study is to evaluate the biocompatibility and antibiofilm actions of two nano-hydroxy apatite (NHA).

Methodology

Nano-hydroxy apatites are biomaterials use in direct contact with living tissues. Therefore, they should be tested for their safety beside assessment of their minimum inhibitory (MIC) and minimum bactericidal concentration (MBC) using broth microdilution method. One hundred and twenty extracted bovine incisors were collected and cleaned to ensure the absence of any defects. Enamel blocks with different size (2 × 2 × 3 mm) and (5 × 5 × 2 mm) were prepared from their labial surfaces using an isomet saw. Enamel blocks are used for detecting the suitable concentration will be used in the following experiments using energy dispersive X-ray analysis (EDX). The remaining enamel blocks divided into 5 equal groups to detect inhibitory effect against bacterial adhesion to the initial enamel caries like lesions using viable count technique beside the antibiofilm activity against mature biofilm of Streptococcus mutans (S. mutans) using confocal laser microscopy. The remaining enamel blocks were used as a representing data for detecting surface topography for each group by using the scanning electron microscopy (SEM).

Result

The data showed safety of NHA suspensions. Additionally, only NHA suspension of large nanoparticle size (NHA-LPS) had MIC of 1.25 mg/ml against S. mutans. Also, have the higher percentages of Ca and P in the enamel blocks. Furthermore, the lowest level of bacterial adhesion was recorded in (group III) treated by NHA-LPS which was non-significantly different with the positive control group V. Biofilm thickness in group IV treated with NHA-small particle size (SPS) recorded high biofilm thickness followed by group III. Interestingly, group III showed greater killing effect against mature biofilm which is slightly higher than the positive control group V. In group III, surface topography revealed very smooth enamel surface with closed pores. Accordingly, NHA-LPS suspension had antiadhesive, antibacterial, and antibiofilm effect against cariogenic S. mutans representing a promising possibility to be recommended for safe effective remineralization.

Minimally Invasive Therapies for the Management of Dental Caries—A Literature Review

In recent years, due to a better understanding of the caries pathology and advances in dental materials, the utilization of non-invasive and minimally invasive techniques that delay/obviate the need for traditional restorations has started gaining momentum. This literature review focuses on some of these approaches, including fluoride varnish, silver diamine fluoride, resin sealants, resin infiltration, chemomechanical caries removal and atraumatic restorative treatment, in the context of their chemistries, indications for use, clinical efficacy, factors determining efficacy and limitations. Additionally, we discuss strategies currently being explored to enhance the antimicrobial properties of these treatment modalities to expand the scope of their application.

Nonrestorative Management of Dental Caries

The World Dental Federation (FDI) policy statement in 2016 advocated evidence-based caries-control measures for managing dental caries. The caries management philosophy has shifted from the traditional surgical manners to minimal intervention dentistry. Minimal intervention dentistry aims to extend the longevity of natural teeth. It places the nonrestorative approaches as a priority. The nonrestorative approaches for caries management aim to tackle the etiological factors of dental caries. Caries can be prevented or reversed by restricting the sugar intake and its frequency in the diet, improving oral hygiene practices, and using fluoride toothpaste. This article aims to present strategies for the nonrestorative management of dental caries, which are divided into four components to address the different etiological factors of dental caries. The first component is controlling dental plaque. Strategies for plaque control include oral hygiene instruction, motivational interviewing, mechanical plaque control, and chemical plaque control. The second component for nonrestorative management is reducing the risk of caries by identifying caries risk factors and protective factors, assessing personal caries risk, and customizing a treatment plan. Evidence-based measures for caries prevention include using fluoride, and dental sealants should be provided. The third component includes topical treatment to remineralise early carious lesions. The last component is long-term follow-up. Appropriate strategy adoption for the nonrestorative management of dental caries prolongs the life span of the teeth and sustains the good oral health of patients.

Comparative evaluation of antimicrobial efficacy of silver diamine fluoride, chlorhexidine varnish with conventional fluoride varnish as a caries arresting agent. An in vivo sodium dodecyl sulfate-polyacrylamide gel electrophoresis study

INTRODUCTION

Silver diamine fluoride (SDF) is employed as an adjunct cariostatic agent in the management of dental caries in high-risk population. Other than fluorides, chlorhexidine (CHX) is the most potent antimicrobial and efficacious agent against Streptococcus mutans.

AIM

The aim of this study is to evaluate and differentiate the efficacy of 38% silver diamine fluoride, CHX varnish, and fluoride varnish on carious primary teeth.

MATERIALS AND METHODS

Ninety children having a count of ≥1 carious lesion were recruited. Thirty-eighty percent silver diamine fluoride or fluoride varnish and CHX varnish were topically applied on the lesion. The primary outcome measured was the arrest of carious lesion (lesion rendered inactive as per the Nyvad criteria) after a follow-up of 14-21 days. Dental biofilm sample was obtained from each child and subsequently assessed for microbial composition by colony-forming unit method before and after treatment followed by protein analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis method.

RESULTS

Average proportion of arrested caries lesions in the SDF group was higher followed by CHX and fluoride varnish groups. Decreased total protein amount was found in SDF group. This proves that there is decrease in microbial load posttreatment in SDF group.

CONCLUSION

Thirty-eight percent SDF is more effective than CHX varnish and fluoride varnish in arresting dentin carious lesions in young children.

Effect of Strontium-Doped Bioactive Glass on Preventing Formation of Demineralized Lesion

This study investigated the effect of strontium-doped bioactive glass (SBAG) on the formation of dental demineralized lesions. Materials and methods: The study materials were 48 sound human tooth specimens with both dentine and enamel, divided equally into four groups: Group 1 (SBAG), Group 2 (SBAG+Fluoride), Group 3 (Fluoride), and Group 4 (Water as control). After 14 days of pH cycling, the surface morphology of the specimens was observed by scanning electron microscopy. Crystal characteristics of the precipitates were assessed by X-ray diffraction (XRD). Micro-CT was used to measure the mineral loss and the depths of the demineralized lesions formed. Results: Exposure of collagen in inter-tubular areas in dentine was seen in the control group (Group 4) but not in Groups 1 to 3. In Group 2, there were obvious granular particles on the surface of the dentine. XRD revealed precipitation of apatites on the surface of the tooth specimens in Groups 1 to 3. The mean lesion depths in dentine were 81.80 μm, 30.68 μm, 39.04 μm, and 146.36 μm in Groups 1 to 4, respectively (p < 0.001). Lesions in enamel were only found in the control group. The mean mineral loss values in the dentine lesions were 1.25 g/cm³, 0.88 g/cm³, 0.87 g/cm³, and 1.65 g/cm³, in Groups 1 to 4, respectively (p < 0.001). Conclusion: Strontium-doped bioactive glass has a preventive effect on the formation of demineralized lesions in enamel and dentine.

Biomineralization of Dental Tissues Treated with Silver Diamine Fluoride

Silver diamine fluoride (SDF) is a dental biomaterial used to arrest dental caries. To better understand SDF's mechanism of action, we examined the localization of silver within the tissues of SDF-treated teeth. Carious primary teeth fixed within 2 min of SDF application (SDF-minutes, n = 3), at 3 wk after SDF application in vivo (SDF-weeks, n = 4), and at 2 y after multiple SDF applications in vivo (SDF-multiple, n = 1) were investigated in this study. Carious primary teeth without SDF application (no-SDF, n = 3) served as controls. Mineral density and structural analyses were performed via micro-X-ray computed tomography and scanning electron microscopy. Elemental analyses were performed through X-ray fluorescence microprobe and energy-dispersive X-ray spectroscopic techniques. SDF-treated teeth revealed higher X-ray-attenuated surface and subsurface regions within carious lesions, and similar regions were not present in no-SDF teeth. Regions of higher mineral density correlated with regions of silver abundance in SDF-treated teeth. The SDF penetration depth was approximated to 0.5 ± 0.02 mm and 0.6 ± 0.05 mm (mean ± SD) for SDF-minutes and SDF-weeks specimens, respectively. A higher percentage of dentin tubular occlusion by silver or calcium phosphate particles was observed in primary teeth treated with SDF-weeks as compared with SDF-minutes. Elemental analysis also revealed zinc abundance in carious lesions and around the pulp chamber. SDF-weeks teeth had significantly increased tertiary dentin than SDF-minutes and no-SDF teeth. These results suggest that SDF treatment on primary teeth affected by caries promotes pathologic biomineralization by altering their physicochemical properties, occluding dentin tubules, and increasing tertiary dentin volume. These seemingly serendipitous effects collectively contribute to the cariostatic activity of SDF.

The Amelogenin-Derived Peptide TVH-19 Promotes Dentinal Tubule Occlusion and Mineralization

In this study, the amelogenin-derived peptide, TVH-19, which has been confirmed to promote mineralization, was evaluated to derive its potential to induce dentinal tubule occlusion. The binding capability of fluorescein isothiocyanate (FITC)-labeled TVH-19 to the demineralized dentin surface was analyzed by confocal laser scanning microscopy (CLSM). Additionally, the sealing function of the peptide was studied through the remineralization of demineralized dentin in vitro. The adsorption results showed that TVH-19 could bind to the hydroxyapatite and demineralized dentin surfaces, especially to periodontal dentin. Scanning electron microscopy analysis further revealed that TVH-19 created mineral precipitates. The plugging rate in the TVH-19 group was higher than that in the PBS group. Moreover, energy-dispersive X-ray spectroscopy (EDX) results indicated that the calcium/phosphorus (Ca/P) ratio of the new minerals induced by TVH-19 was close to that of the hydroxyapatite. Attenuated total internal reflection-Fourier transform infrared (ATR-FTIR) spectrometry and X-ray diffraction (XRD) results indicated that the hydroxyapatite crystals formed via remineralization elongated the axial growth and closely resembled the natural dentin components. These findings indicate that TVH-19 can effectively promote dentin sealing by binding to the periodontal dentin, promoting mineral deposition, and reducing the space between the dentin tubules.

Study of Demineralized Dental Enamel Treated with Different Fluorinated Compounds by Raman Spectroscopy

BACKGROUND

Current diagnostic methods for enamel caries detection are unable to detect caries lesions (incipient caries lesion) at a very early stage.

OBJECTIVE

This study aims to determine the remineralizing effect of three fluorinated compounds on demineralized subsurface tooth enamel using Raman spectroscopy characterization.

MATERIAL AND METHODS

In this experimental study, sixty impacted 3^rd molars, with intact anatomical crowns recently extracted and without structural defects, were sectioned longitudinally in a mesio-distal direction using a diamond disc, obtaining two working surfaces (buccal and lingual). The 120 working surfaces obtained were immersed for 96 h in a demineralization solution at 37°C in order to demineralize the enamel surface. All samples were randomly divided into three groups (n=30 each) and their surfaces were treated with silver diamine fluoride (SDF), Difluoride silane (DSF), and acidulated phosphate fluoride (APF), and with no treatment undertaken in the control group (CG). The samples were immersed in alternating solutions for demineralization and remineralization at pH 4.4 and pH 7.0, respectively. The results were analyzed with Principal Component Analysis (PCA) in order to determine the variance.

RESULTS

The most important difference (91.7%) is observed in APF group between PCA1 respect to PCA2, followed by DSF (91.5%) and SDF (76.3%) respectively. Therefore, a greater remineralization in the dental enamel can be observed by the three experimental groups.

CONCLUSION

The APF and DSF have the effect of recovering the mineralization of dental enamel, except for the SDF. Functional groups OH^- and PO43- were identified in all subsurface.

Shear bond strength and interfacial analysis of high-viscosity glass ionomer cement bonded to dentin with protocols including silver diammine fluoride

PURPOSE

High-viscosity glass ionomer cements (HV-GICs) are reinforced with ultrafine, highly reactive glass particles, as well as a higher-molecular-weight polyalkenoic acid component. Silver diammine fluoride (SDF) is an agent with promising activity against active caries. The present study aimed to evaluate the shear bond strength (SBS) and interfacial morphology of a new HV-GIC bonded to dentin after treatment with various adhesive protocols including SDF.

METHODS

HV-GIC cylinders were bonded to dentin after various surface treatments (6 groups, n = 22): water; polyalkenoic acid; SDF; SDF + potassium iodide (KI); SDF + KI + polyalkenoic acid; SDF + KI + two weeks of storage in water + polyalkenoic acid. For each group, 20 samples were tested for SBS after 48 h, and 2 samples were cut and subjected to environmental scanning electron microscopy (E-SEM) and energy-dispersive X-ray (EDX) analysis.

RESULTS

No significant differences in SBS were found between any of the protocols tested. However, E-SEM and EDX images showed different interfaces when SDF was applied.

CONCLUSION

SDF has no influence on the adhesion of HV-GIC to sound dentin and could potentially improve the cario-resistance of the dentin/HV-GIC interface.

Spatial variation and health risk assessment of fluoride in drinking water in the Chongqing urban areas, China

Fluoride is an essential trace element for humans, and its deficiency or excess in the environment could lead to disease. To investigate the spatial distribution and health risk assessment of fluoride (F^-) in drinking water, 302 tap water samples from Chongqing urban areas, China, were collected to analyze F^- using an ion chromatograph. The results showed that (1) F^- concentration in drinking water ranged from 0.100 to 0.503 mg/L, with an average of 0.238 ± 0.045 mg/L. (2) The spatial autocorrelation analysis showed that high-low clusters were mostly located in Dadukou District and Beibei District, while low-low clusters were mainly in southern Banan District. (3) The fluoride average daily doses of children, teens and adults were 0.030, 0.029 and 0.031 mg/(kg day). (4) Hazard quotients of excessive fluoride (HQ_e) of children, teens and adults were 0.51 ± 09, 0.49 ± 0.09 and 0.52 ± 0.10, respectively (inferior to 1.00), whereas hazard quotients of inadequate fluoride (HQ_i) of those groups were 1.21 ± 0.26, 1.23 ± 0.26 and 1.15 ± 0.25, respectively (superior to 1.00). Therefore, average daily fluoride intake of residents with drinking water was inadequate. This could pose dental caries and osteoporosis threats for residents from Chongqing urban areas.

Effectiveness of in vitro primary coronal caries prevention with silver diamine fluoride - Chemical vs biofilm models

OBJECTIVES

The main goal of this study was to investigate the effectiveness of SDF and its individual components, silver (Ag⁺) and fluoride (F^-) ions, in preventing enamel demineralization using biofilm and chemical models.

METHODES

Polished human enamel specimens were assigned to five treatment groups (n = 18 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 (DIW). Treatments were applied once to sound enamel. In the biofilm model, specimens were demineralized by aerobic overnight incubation using cariogenic bacteria isolated from human saliva in brain heart infusion supplemented with 0.2 % sucrose for three days. In the chemical model, enamel specimens were immersed in a demineralizing solution containing 0.1 M lactic acid, 4.1 mM CaCl₂, 8.0 mM KH₂PO₄, 0.2 % Carbopol 907, pH adjusted to 5.0 for five days. Vickers surface microhardness was used to determine the extent of enamel demineralization. Data were analyzed using one-way ANOVA.

RESULTS

In the chemical model, there was no statistically significant difference between SDF and SDF + KI in preventing coronal caries (p < 0.0001). In the biofilm model, SDF + KI was significantly less effective in preventing demineralization than SDF (p < 0.0001). In both models, SDF and SDF + KI were superior in their ability to prevent caries lesion formation than AgNO₃ and DIW.

CONCLUSION

KI application after SDF treatment appears to impair SDF's ability to prevent biofilm-mediated but not chemically induced demineralization.

CLINICAL SIGNIFICANCE

SDF may be a viable option in preventing primary coronal caries.

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.

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.

The Effect of Physician Oral Health Services on Dental Use and Expenditures under General Anesthesia

BACKGROUND

Despite early evidence touting the effectiveness of physician-provided oral health services (POHS), recent evidence suggests these services might have little impact on caries-related outcomes in children. General anesthesia (GA) is often used to treat early childhood caries and may be considered the most extreme utilization outcome. We sought to assess the impact of POHS utilization on dental GA utilization and expenditures.

METHODS

We used the Medicaid claims of a birth cohort of children born in 2008 in North Carolina (N = 32,558) to determine the impact of POHS on dental utilization and expenditures under GA for individual children. Children were followed until their eighth birthday. We analyzed the association of the number of prior POHS visits with visit-specific outcomes of dental treatment under GA using population-averaged models fit with generalized estimating equations with exchangeable working correlation structure.

RESULTS

Children with 2 or more previous POHS visits had reduced odds of GA (odds ratio [OR] = 0.93; confidence interval [CI], 0.87-0.99; P = 0.029) and expenditures ($114; CI,-$152.61 to -$75.19; P < 0.001) compared to those without physician-provided oral health visits, adjusting for age, sex, race/ethnicity, and geographic residence. Dental expenditures did not differ between POHS and non-POHS subjects at non-GA visits.

CONCLUSIONS

POHS decreased the odds of having dental GA treatment and dental expenditures at GA visits. The role of physicians in oral health care can reduce the impact on the most severe outcome-treatment under general anesthesia.

KNOWLEDGE TRANSFER STATEMENT

The results of this study have important financial implications for state Medicaid programs and disease management programs trying to mitigate the costs of treating early childhood caries under general anesthesia. Children who receive physician oral health care are less likely to use and more likely to save money on general anesthesia to complete dental treatment.

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.