Prevention of Dental Caries by Silver Diamine Fluoride

The use of silver diamine fluoride (SDF) for management of dental caries has gained considerable attention due to recent regulatory clearance in the United States. The primary focus of policies, presentations, and publications has been the arrest of caries lesions (cavities) because of the material's unique ability to non-invasively achieve this elusive and clinically important goal. However, SDF also has proven efficacy in prevention, ie, decreasing the incidence of new caries lesions. Analysis of nine clinical trials in children shows that SDF prevented 61% of new lesions compared to controls. To prevent one new caries lesion, clinicians need to treat four primary teeth (one patient) or 12.1 permanent molars (three patients) with SDF. The preventive effect appears to be immediate and maintains at the same fraction over time. Direct comparisons of SDF applied once per year with alternative treatments show that SDF is more effective than other topical fluorides placed two to four times per year and more cost-effective than dental sealants. Enamel lesions may be even more responsive than cavitated dentin lesions. Annual application of SDF to high-risk surfaces (eg, mesial surfaces of permanent first molars where the distal surface of the second primary molar is carious) in patients with any risk of new caries lesions appears to be the most cost-effective approach available to prevent dental caries. SDF is an underutilized evidence-based preventive agent for dental caries.

Evidence-Based Dentistry Update on Silver Diamine Fluoride

This article reviews current evidence on the effectiveness of silver diamine fluoride (SDF) as a caries arresting and preventive agent. It provides clinical recommendations around SDF's appropriate use as part of a comprehensive caries management program. Systematic reviews confirm that SDF is effective for caries arrest on cavitated lesions in primary teeth and root caries in the elderly. It may also prevent new lesions. Application is easy, noninvasive, affordable, and safe. Although it stains the lesions dark as it arrests them, it provides clinicians with an additional tool for caries management when esthetics are not a primary concern.

The Effect of Silver Diamine Fluoride in Preventing Caries in the Primary Dentition: A Systematic Review and Meta-Analysis

OBJECTIVES

To investigate whether silver diamine fluoride (SDF) is effective in preventing new caries lesions in primary teeth when compared to placebo or active treatments.

METHODS

Systematic review (CRD42016036963) of controlled clinical trials. Searches were performed in 9 electronic databases, 5 registers of ongoing trials, and reference lists of identified review articles. Two researchers carried out data extraction and quality appraisal independently. The primary outcome was the difference in caries increment (decayed, missing, and filled surfaces or teeth - dmfs or dmft) between SDF and control groups. These differences were pooled as weighted mean differences (WMD) and prevented fractions (PF).

RESULTS

Searches yielded 2,366 unique records; 6 reports of 4 trials that randomized 1,118 and analyzed 915 participants were included. Two trials compared SDF to no treatment, 1 compared SDF to placebo and sodium fluoride varnish (FV), and 1 compared SDF to high-viscosity glass ionomer cement (GIC). All studies had at least 1 domain with unclear or high risk of bias. After 24 months of follow-up, in comparison to placebo, no treatment, and FV, SDF applications significantly reduced the development of new dentin caries lesions (placebo or no treatment: WMD = -1.15, PF = 77.5%; FV: WMD = -0.43, PF = 54.0%). GIC was more effective than SDF after 12 months of follow-up but the difference between them was not statistically significant (WMD, dmft: 0.34, PF: -6.09%).

CONCLUSION

When applied to caries lesions in primary teeth, SDF compared to no treatment, placebo or FV appears to effectively prevent dental caries in the entire dentition. However, trials specifically designed to assess this outcome are needed.

[Allergies to dental materials and effectiveness of treatment in the north-eastern region of Hungary]

The recognition and treatment of allergy is a great challenge for all fields of medicine. The high prevalence of allergic reactions to dental materials and the related financial burden of their treatment make investigation of this disease very important. Our investigation was carried out on patients assigned to our outpatient department for dental allergy test between 1996 and 1998. We determined the distribution of gender and age among the allergic patients in the examined population. We also studied the prevalence of allergic reactions to different dental allergens and the distribution of dental allergens. In a follow-up study we determined the proportion of those patients, who were retreated in conformity with the results of epicutan tests and we followed up the positive effects of these treatments. We have found that dental allergy occurred five times more frequently in women (84%) than in men (16%) and the most affected age group was between 20 to 39 and 40-49 years (31%). Seventy-five percent of the patients suffered from a combination of metal and polymer allergy. The most frequent metal allergen was TEGDMA (triethylene glycol dimethacrylate) (49.7%). The suggested treatment plan was carried out in 63% of the allergic patients. The applied treatment was successful in 48% of these cases. We experienced that 48% of these patients got rid of their earlier signs and symptoms.

[Nanosilver - harmful effects of biological activity]

Nanosilver, also identified as colloidal silver, has been known and used for ages to combat diseases or prolong food freshness. It usually occurs in the form of a suspension consisting of particles of size < 100 nm. Due to its specific properties, silver nanoparticles are used in many technologies to produce medical devices, textiles, conductive materials or photovoltaic cells. The growing popularity of nanosilver applications increases the number of people occupationally exposed to this substance. Potential exposure routes for silver nanoparticles are through dermal, oral and inhalation pathways. Silver nanoparticles may be absorbed through the lungs, intestine, and through the skin into circulation and thus may reach such organs as the liver, kidney, spleen, brain, heart and testes. Nanosilver may cause mild eyes and skin irritations. It can also act as a mild skin allergen. Inhalation of silver nanoparticles mainly affects the lungs and liver. It has been demonstrated that silver nanoparticles may be genotoxic to mammalian cells. There are some alarming reports on the adverse effects of silver nanoparticles on reproduction of experimental animals. Exposure to silver nanoparticles may exert a neurotoxic effect and affect cognitive functions, causing the impairment of short-term and working memory. Maximum admissible concentration (MAC) for the inhalable fraction of silver of 0.05 mg/m3 is currently binding in Poland. In light of toxicological studies of silver nanoparticles it seems reasonable to update the hygiene standards for silver with nanoparticles as a separate fraction.

Antimicrobial silver: uses, toxicity and potential for resistance

This review gives a comprehensive overview of the widespread use and toxicity of silver compounds in many biological applications. Moreover, the bacterial silver resistance mechanisms and their spread in the environment are discussed. This study shows that it is important to understand in detail how silver and silver nanoparticles exert their toxicity and to understand how bacteria acquire silver resistance. Silver ions have shown to possess strong antimicrobial properties but cause no immediate and serious risk for human health, which led to an extensive use of silver-based products in many applications. However, the risk of silver nanoparticles is not yet clarified and their widespread use could increase silver release in the environment, which can have negative impacts on ecosystems. Moreover, it is shown that silver resistance determinants are widely spread among environmental and clinically relevant bacteria. These resistance determinants are often located on mobile genetic elements, facilitating their spread. Therefore, detailed knowledge of the silver toxicity and resistance mechanisms can improve its applications and lead to a better understanding of the impact on human health and ecosystems.

A case of argyria: multiple forms of silver ingestion in a patient with comorbid schizoaffective disorder

Argyria is a rare cutaneous manifestation of silver deposits in the skin, characterized by a grayish blue discoloration, particularly in sun-exposed areas. We report the case of a patient with a history of schizoaffective disorder and type 2 diabetes mellitus who presented with argyria of the face and neck. The patient had a history of ingesting colloidal silver proteins (CSPs) for approximately 10 years as a self-prescribed remedy for his medical conditions. Colloidal silver protein has gained popularity among patients who seek alternative medical therapies. Argyria is the most predominant manifestation of silver toxicity. It is unclear if our patient began taking CSP because of his schizoaffective disorder or if silver toxicity may have induced somatic delusions; however, it is important for physicians to have a thorough understanding of alternative therapies on the market. We present a detailed background on silver ingestion and its systemic effects.

[Damaging effect of "Poviargol" on mice peritoneal macrophage plasma membrane]

The damaging effect of "Poviargol", a substance containing silver nanoparts, was studied. It was shown that the damaging effect of "Poviargol" took place from the concentration of 2 mkg/ml and got its maximum at 10-12 microg/ml. Decrease of the incubation temperature from 30 to 4 degreesC led to amplification of the membrane-acting effect of "Poviargol"; however, inverse relation was observed in the range from 37 to 30 degreesC. The damaging effect of "Poviargol" increased when pH of the incubating medium was raised to 8.4 and also when the concentration of calcium ions in the incubation medium was raised to 8 mmol/l. The damaging effect decreased when pH of the incubation medium was reduced to 6.3, as well as in the presence of radioprotector serotonin. Our study allows us to suppose that reactive oxygen species and lipid peroxidation make a substantial contribution to the damaging effect of "Poviargol" on the macrophage plasma membrane.

Nanosilver in consumer products and human health: more information required!

Commenting on "120 Years of Nanosilver History: Implications for Policy Makers" (Environ. Sci. Technol.2011, 45, 1177-1183). The title of the article seduces readers to the impression that we can look back at more than a century of safe use of nanosilver. In this context, colloidal silver and nanosilver have been sometimes used as synonyms. Historically, the term "colloidal silver" refers to dispersed silver particles encompassing a size range of 10-1000 nm. Following scientific definitions, "colloid" stands for freely dispersed particles in a fluid (heterogenic) phase irrespective of its size distribution, while the term "nanosilver" is used for categorization by size. Of course, just the labeling as such neither necessarily implies new hazard properties nor any specific risks; however, uncertainties and data gaps at many levels call for careful consideration and usually should take effect as alert signal for regulatory toxicologists all over the world. Within the frame of this short commentary, we would like to focus on some unclarified issues related to consumer products.

120 years of nanosilver history: implications for policy makers

Nanosilver is one nanomaterial that is currently under a lot of scrutiny. Much of the discussion is based on the assumption that nanosilver is something new that has not been seen until recently and that the advances in nanotechnology opened completely new application areas for silver. However, we show in this analysis that nanosilver in the form of colloidal silver has been used for more than 100 years and has been registered as a biocidal material in the United States since 1954. Fifty-three percent of the EPA-registered biocidal silver products likely contain nanosilver. Most of these nanosilver applications are silver-impregnated water filters, algicides, and antimicrobial additives that do not claim to contain nanoparticles. Many human health standards for silver are based on an analysis of argyria occurrence (discoloration of the skin, a cosmetic condition) from the 1930s and include studies that considered nanosilver materials. The environmental standards on the other hand are based on ionic silver and may need to be re-evaluated based on recent findings that most silver in the environment, regardless of the original silver form, is present in the form of small clusters or nanoparticles. The implications of this analysis for policy of nanosilver is that it would be a mistake for regulators to ignore the accumulated knowledge of our scientific and regulatory heritage in a bid to declare nanosilver materials as new chemicals, with unknown properties and automatically harmful simply on the basis of a change in nomenclature to the term "nano".

Silver dressings--do they work?

The metal silver is well known to have antimicrobial properties and this underlies its incorporation into the many types of silver releasing wound dressings available in the UK. These products are classed as 'advanced' dressings and were developed primarily for difficult to heal wounds, chronic ulcers and extensive burns.1 The use of silver dressings has increased rapidly in recent years in the UK, with the amount spent on such products in the NHS being around pound23million in 2005 and around pound25million in 2006/7.2(,)3 The latter figure represents a quarter of the total cost of wound dressings, with one seventh of the wound dressing items prescribed being silver dressings.3 Here we discuss the evidence on the place of silver dressings in burns, chronic ulcers and acute wounds.

Silver nasal sprays: misleading Internet marketing

Long-term use of silver-containing products is associated with a permanent bluish-gray discoloration of the skin known as argyria, but they remain widely available despite several measures by the FDA to regulate them. Several recent case reports have described the occurrence of argyria as a result of using these "natural" products. We used the five most common Internet search engines to find Web sites providing information on silver-containing nasal sprays. Of 49 Web sites analyzed, only 2 (4%) mentioned argyria as a possible complication, although 30 (61%) did caution against long-term use. Eight sites (16%) made specific claims about the health benefits of the product. All 49 sites (100%) provided direct or indirect links to buy silver-containing nasal sprays. We conclude that information about silver-containing nasal sprays on the Internet is misleading and inaccurate. Therefore, otolaryngologists should be aware of the misinformation their patients may be receiving about these products.

Ion uptake into demineralized dentine from glass ionomer cement following pretreatment with silver fluoride and potassium iodide

BACKGROUND

Diamine silver fluoride (Ag(NH3)2F), referred to as AgF, has been shown to provide a pronounced antimicrobial action against caries. The clinical application of this material has been limited by the staining associated with both teeth and tooth coloured restorative materials. The application of potassium iodide (KI) after AgF eliminates stain formation. The purpose of this study was to determine if a prior application of silver fluoride and potassium iodine to demineralized dentine affected the uptake of strontium and fluoride from a glass ionomer cement restoration.

METHOD

Three cavities were prepared in each of five recently extracted human third molars. The cavities were demineralized and treated as follows. In each tooth, one cavity was left as a control, one cavity was restored with glass ionomer cement and one cavity was treated with 1.8M AgF and a saturated KI solution and then restored with glass ionomer cement. The penetration of the various elements into demineralized dentine was measured by their relative percentage weights using electron probe microanalysis (EPMA).

RESULTS

Fluoride uptake was significantly higher in the AgF and KI treated samples compared to the other two samples and significantly higher in the glass ionomer restored sample compared to the control. The application of AgF and KI did not significantly interfere with the transfer of strontium from glass ionomer cement into dentine. Silver and iodine deposits were present in the demineralized dentine treated with AgF and KI.

CONCLUSIONS

The application of AgF and KI onto dentine prior to the placement of glass ionomer cement did not significantly affect the strontium uptake into the subjacent demineralized dentine and the fluoride levels in this zone were significantly increased.

The safety and efficacy of dressings with silver - addressing clinical concerns

With the increasing use of silver as a topical application in wound care, concerns focussing on its role are bound to arise. These concerns, which centre on issues such as resistance and toxicity, clinical efficacy and cost-effectiveness, need to be addressed and openly discussed so that they are viewed from a rational perspective. While clinical efficacy and safety, along with cost-benefit, are of obvious interest, the origin of some of these concerns is a matter of debate. The silver-containing dressing segment of the medical device market is of huge commercial importance, and, consequently, marketing and promotional issues occasionally obscure the evidence that clinicians need to have in order that they may provide appropriate treatment for their patients. The impact of silver application on the wound bioburden needs to be examined carefully to heighten our awareness of any deleterious effects on the healing process, without inducing any unfounded anxieties.

Enhancement of fluoride release from glass ionomer cement following a coating of silver fluoride

BACKGROUND

This study investigated the extent to which a coating of 10% silver fluoride (AgF) on discs of glass jonomer cements (GIGs) would enhance the release of fluoride ion into eluting solutions at varying pH.

MATERIALS AND METHODS

Forty discs each of Fuji LX, Fuji VII and of Vitrebond were prepared in a plastic mould. Twenty discs of each material were coated for 30 seconds with a 10% solution of AgF. Five discs each of coated and uncoated material were placed individually in 4m1 of differing eluant solutions. The eluant solutions comprised deionized distilled water (DDW) and three separate acetate buffered solutions at pH 7, pH 5 and pH 3. After 30 minutes the discs were removed and placed in five vials containing 4m1 of the various solutions for a further 30 minutes. This was repeated for further intervals of time up to 216 hours, and all eluant solutions were stored. Fluoride concentrations in the eluant solutions were estimated using a fluoride specific electrode, with TISAB IV as a metal ion complexing and ionic concentration adjustment agent. Cumulative fluoride release patterns were determined from the incremental data.

RESULTS

The coating of AgF greatly enhanced the level of fluoride ion release from all materials tested. Of the uncoated samples, Vitrehond released the greater concentrations of fluoride ion, followed by Fuji VII. However, cumulative levels of fluoride released from coated samples of the GICs almost matched those from coated Vitrebond.

CONCLUSIONS

It was concluded that a coating of 10% AgF on GICs and a resin modified GIC greatly enhanced the concentration of fluoride released from these materials. This finding might be applied to improving protection against recurrent caries, particularly in high caries risk patients, and in the atraumatic restorative technique (ART) of restoration placement.

A discussion of silver as an antimicrobial agent: alleviating the confusion

Within the last 3 to 5 years, many silver-based antimicrobial dressings have become available and more are on the way. However, sometimes dressing manufacturers and authors make claims and send messages that conflict with data and conclusions in the literature, creating confusion for clinicians. A literature review of six relevant and frequently discussed topics was conducted. Pre-clinical and clinical study data suggest that: a) bacterial resistance to silver may occur, b) silver dissociation is affected by the test medium used, c) bactericidal activity differences may be a function of the bacterial strain used for testing, d) higher rather than lower levels of silver may be needed because Ag+ binds to proteins and nucleic acids, e) rapid delivery of silver (ie, rate of kill) may be a positive factor when considering prevention of silver resistance and biofilm formation, and f) based on the vast majority of in vivo studies available, silver does not adversely effect viable cells; thus, is not cytototoxic. Continued research into the implications of the data is warranted.

Argyria secondary to ingestion of homemade silver solution

Argyria is a rare skin disease caused by cutaneous deposition of silver granules in the skin as a result of exposure to silver substrate or ingestion of silver salt. This report describes a patient with generalized argyria caused by ingestion of homemade colloidal silver solution. The patient learned about the uses of the silver solution and its preparation at a convention for "natural medicine."

Exposure-Related Health Effects of Silver and Silver Compounds: A Review

A critical review of studies examining exposures to the various forms of silver was conducted to determine if some silver species are more toxic than others. The impetus behind conducting this review is that several occupational exposure limits and guidelines exist for silver, but the values for each depend on the form of silver as well as the individual agency making the recommendations. For instance, the American Conference of Governmental Industrial Hygienists has established separate threshold limit values for metallic silver (0.1 mg/m3) and soluble compounds of silver (0.01 mg/m3). On the other hand, the permissible exposure limit (PEL) recommended by the Occupational Safety and Health Administration and the Mine Safety and Health Administration and the recommended exposure limit set by the National Institute for Occupational Safety and Health is 0.01 mg/m3 for all forms of silver. The adverse effects of chronic exposure to silver are a permanent bluish-gray discoloration of the skin (argyria) or eyes (argyrosis). Most studies discuss cases of argyria and argyrosis that have resulted primarily from exposure to the soluble forms of silver. Besides argyria and argyrosis, exposure to soluble silver compounds may produce other toxic effects, including liver and kidney damage, irritation of the eyes, skin, respiratory, and intestinal tract, and changes in blood cells. Metallic silver appears to pose minimal risk to health. The current occupational exposure limits do not reflect the apparent difference in toxicities between soluble and metallic silver; thus, many researchers have recommended that separate PELs be established.

Long-term use of silver containing nose-drops resulting in systemic argyria

Generalized argyria is a silver intoxication that results in pigmentation due to deposition of silver in the skin and mucous membranes. Compared to several decades ago, argyria is now relatively rare. We report a case of generalized argyria after continous use of argyrophedrine nosedrops in the last ten years. Argyria should be taken into consideration when a patient presents with a blue-grey discoloration of the skin, particulary in areas exposed to the sun.

Long-term effects of Ag-containing alloys on mucous tissue present in biopsy samples

The aim of this study was to investigate the long-term effects of alloys containing silver (mainly Ag-Sn alloy) on oral mucous tissue. We observed biopsy tissue specimens from patients diagnosed as having amalgam tattoo and/or metal pigmentation by light and electron microscopy and electron-probe microanalysis (EPMA). In most cases, Ag-Sn alloy was present in the tissue but it could not be confirmed if the alloy originated from amalgam. Distributions of both Ag-S and Ag-Sn have typical patterns. Most Ag forms Ag2S and is stably deposited in three patterns along the collagen, basement membrane, and fibrous cells without inducing any host reaction. On the other hand, Sn forms large granules that contain Ag, S, C, N, P, and Ca, and is in soft state in the tissue. Tissue reactions to the alloy become weaker as time passes.

[Argyria--an almost-forgotten dyschromia]

A 79-year-old woman presented with a long history of grey-blue discoloration of the light-exposed areas. Her face, forearms, and the backs of both hands were affected. The proximal parts of her fingernails were impressively discolored, but her toenails were not affected. The patient reported that she had received oral therapy with the silver-containing drug Gastrarctin in 1959. The diagnosis of argyria was confirmed by documenting high tissue levels of silver in light-exposed skin. Argyria has become uncommon as medications containing silver are no longer employed and occupational protection for those with exposure to silver salts has become more refined.

Abnormally high fluoride levels in commercial preparations of 40 per cent silver fluoride solution: contraindications for use in children

Although a 40 per cent solution of silver fluoride would be expected to contain 6 per cent fluoride (60,000 ppm), F-levels of 100,000 ppm and 120,000 ppm were found in 14 commercial samples analysed at The University of Western Australia in 1993 and 1994. To determine whether F-levels in 40 per cent AgF preparations have remained high, the present investigation was aimed at analysing different batches of commercial preparations obtained more recently. Fluoride ion analysis was carried out on 24 AgF samples using the Ion-Selective Electrode technique. Independent analyses of the same samples were carried out by a private chemical testing laboratory (Genalysis). Ten samples supplied by Agson Chemical Export were found to contain between 75,000 and 100,000 ppm F-: Genalysis reported 80,000 to 120,000 ppm. Fourteen samples supplied by Southern Dental Industries were found to contain between 70,000 and 120,000 ppm F-; Genalysis reported 88,000 to 108,000 ppm F-. These results confirm significantly higher than expected F-levels (ANOVA p < 0.05) in commercial preparations of 40 per cent AgF. The solutions tested were found to contain a mixture of ammonium fluoride, sodium or potassium fluoride, and silver fluoride. The additional presence of silver difluoride and hydrofluoric acid resulting from the manufacturing process has been suggested as an explanation for the much higher than expected levels of fluoride ion. In view of possible toxicity of 40 per cent AgF in young children, it is concluded that such a highly concentrated solution should not be used clinically; instead, lower strength AgF solutions should be investigated for their efficacy in caries treatment.

Safety issues related to the use of silver fluoride in paediatric dentistry

Due to its exceedingly high fluoride content, 40% silver fluoride solution has the potential to cause fluorosis when used in young children. In vitro testing conducted in the present investigation indicates that application of 40% silver fluoride to deep carious lesions or its use as a 'spot' application agent could result in 3 to 4 mg of fluoride reaching the systemic circulation. As scientifically-based clinical trials on the safety of 40% silver fluoride have not been conducted, it would be appropriate for it to be withdrawn from further clinical use until proper testing and evaluation have been carried out. In view of the possibility that lower strength solutions of silver fluoride (1-4%) may be just as effective as 40% in 'arresting' deep caries, testing should focus on such solutions, particularly as the potential for toxicity from their fluoride content would be reduced by a factor of 10-40.

Silver products for medical indications: risk-benefit assessment

BACKGROUND

Legitimate medicinal use of silver-containing products has dramatically diminished over the last several decades. Recently, however, some manufacturers have begun to enthusiastically promote oral colloidal silver proteins as mineral supplements and for prevention and treatment of many diseases. Indiscriminate use of silver products can lead to toxicity such as argyria.

OBJECTIVE

To assist health care professionals in a risk versus benefit assessment of over-the-counter silver-containing products, we herein examine the following issues: historical uses, chemistry, pharmacology, clinical toxicology, case reports of adverse events in the literature, and the recent promotion of over-the-counter silver products. Other sources of silver exposure (including environmental and dietary) and EPA exposure standards are discussed. A list of currently available silver products is provided for easy reference and screening.

CONCLUSIONS

We emphasize the lack of established effectiveness and potential toxicity of these products.

[Are Ag-points, gutta percha and amalgam still applicable for apical sealing?]

Nowadays Ag-points, gutta percha and amalgam are widely used as orthograde or retrograde root-filling materials. The biocompatibility of these materials however remains debatable. Ag-points are easy to manipulate and when used together with an appropriate cement, offer an adequate seal. Yet an important disadvantage is the susceptibility to corrosion resulting in argyrosis and inflammatory reaction. Tissue cultures proved these corrosion by products to be highly cytotoxic. Other investigations, reported that the inflammatory tissue response seen with gutta percha, may be due to small amounts of additives included in gutta percha. Equally, there is no unanimity concerning the biocompatibility of amalgam, and the extent of corrosion and inflammatory reaction is possibly related to the composition of the amalgam used. Nevertheless in vivo studies demonstrated that, when freshly mixed amalgam, gutta percha or Ag-points are implanted in the femur of rats, mature bone was formed in direct contact with these materials.