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.
Key points
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Silver diamine fluoride incorporates the antibacterial effects of silver and the remineralizing actions of a high-concentration fluoride. It effectively arrests the disease process on most lesions treated.
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Systematic reviews of clinical trials confirm the effectiveness of silver diamine fluoride as a caries-arresting agent for primary teeth and root caries and its ease of use, low cost, and relative safety.
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No caries removal is necessary to arrest the caries process, so the use of silver diamine fluoride is appropriate when other forms of caries control are not available or feasible.
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A sign of arrest is the dark staining of the lesions and affected tooth structures. That could be a deterrent for patients who have esthetic concerns. A thorough informed consent is recommended to ensure high patient satisfaction.
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Silver diamine fluoride use for caries control is recommended as part of a comprehensive caries management program, where individual needs and risks are considered.
Introduction
The global burden of oral disease and the negative social and economic effect associated with it, are a growing problem worldwide.
The widespread use of water fluoridation and fluoride-containing oral products produced significant decreases in the prevalence and severity of dental caries over the last 70 years. However, the benefits of these prevention interventions have not materialized in all segments of society in most countries. Free sugars and processed carbohydrates as a component of diet have increased in many countries, both developed and developing alike. As Thompson and colleagues have shown, lower income groups are particularly vulnerable to high dietary sugar intake. The result has been a disparity in caries experience across socioeconomic groups. In the United States and other high-income countries, untreated dental decay in children is strongly patterned by income and ethnicity, mainly owing to cost and limited availability and/or access to services. In lower income groups, much of the caries goes untreated, resulting in severe disease levels that leads to pain, expense, and a decreased quality of life for the affected children and their families.
Even when dental services are accessible, traditional restorative treatment can be difficult to deliver to young children with severe disease and those with special management considerations. To address this difficulty, advanced forms of behavior management like sedation and/or general anesthesia are often used, which increase the cost and the risk for the patient and the dentist. Elderly patients often face similar challenges, because increasing rates of untreated decay can severely affect their quality of life, and the difficulties of receiving dental care are accentuated by limitations with mobility and other comorbidities.
When it comes to prevention, epidemiologic studies indicate that when the bacterial challenge is high or the salivary components are lacking, natural remineralization or that aided by fluoride products is insufficient to prevent or arrest the caries process. Thus, there is an urgent need to find ways to beneficially modify the biofilm and to enhance the remineralization process to decrease caries experience and attain improved outcomes of oral health. This situation calls for a paradigm change in caries prevention and management. Specifically, we need more effective, affordable, accessible, and safe treatments that are easy to implement in different settings, and are available to the most vulnerable populations.
Silver diamine fluoride (SDF), a clear liquid that combines the antibacterial effects of silver and the remineralizing effects of fluoride, is a promising therapeutic agent for managing caries lesions in young children and those with special care needs that has only recently become available in the United States. Multiple in vitro studies document its effectiveness in reducing specific cariogenic bacteria and its remineralizing potential on enamel and dentin. Its in vivo mechanism(s) of action are a subject of ongoing research. What is currently understood is that the fluoride component strengthens the tooth structure under attack by the acid byproducts of bacterial metabolism, decreasing its solubility, but SDF may also interfere with the biofilm, killing bacteria that cause the local environmental imbalance that demineralizes dental tissues. Thus, SDF becomes one of the tools available to address caries by modifying the bacterial actions on the tissue while enhancing remineralization.
Numerous systematic reviews substantiate SDF’s efficacy for caries arrest in primary teeth, and arrest and prevention of new root caries lesions. It meets the US Institute of Medicine’s 6 quality aims of being :
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Safe—clinical trials that have used it in more than 3800 individuals have reported no serious adverse events ;
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Effective—arrests approximately 80% of treated lesions ;
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Efficient—can be applied by health professionals in different health and community settings with minimal preparation in less than 1 minute;
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Timely—its ease of application can allow its use as an intervention agent as soon as the problem is diagnosed;
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Patient centered—is minimally invasive and painless, meeting the immediate needs of a child or adult in 1 treatment session; and
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Equitable—its application is equally effective and affordable; with the medicament costing less than $1 per application, it is a viable treatment for lower income groups.
The only apparent drawback is that as the caries lesions become arrested, the precipitation of silver byproducts in the dental tissues stain the lesions black, which can be a deterrent for its use in visible areas ( Figs. 1–4 ).
Systematic syntheses of clinical trials’ findings constitute the highest level of evidence and are essential to inform evidence-based guidelines and set the standard of care in all settings of dental practice. This article presents and discusses the findings of systematic reviews and metaanalysis of SDF as a treatment for caries arrest and prevention.
Background
Silver compounds, especially silver nitrate, have been used in medicine to control infections for more than a century. In dentistry, reports of use of silver nitrate are well-documented for caries inhibition and, before the twentieth century, silver nitrate was firmly entrenched in the profession as a remedy for “hypersensitivity of dentin, erosion and pyorrhea, and as a sterilizing agent and caries inhibitor in deciduous as well as in permanent teeth.” Howe’s solution (ammoniacal silver nitrate, 1917), was reported to disinfect caries lesions and continued to be used for nearly one-half of a century as a sterilizing and disclosing agent for bacterial invasion of dentin to avoid direct pulp exposures, to detect incipient lesions, and to disclose leftover carious dentin.
The relationship of fluorides and caries prevention had been well-established through epidemiologic observations, chemical studies, animal experiments, and clinical trials beginning in the early decades of the twentieth century. It is now well-known that, when fluoride combines with enamel or dentin, it greatly reduces their solubility in acid, promotes remineralization, and results in a reduction of caries.
The use of ammoniacal silver fluoride for the arrest of dental caries was pioneered by Drs Nishino and Yamaga in Japan, who developed it to combine the actions of F − and Ag + and led to the approval of the first SDF product, Saforide (Bee Brand Medico Dental Co, Ltd, Osaka, Japan) in 1970. Each milliliter of product contains 380 mg (38 w/v%) of Ag(NH 3 ) 2 F. They described its effects for prevention and arrest of dental caries in children, prevention of secondary caries after restorations, and desensitization of hypersensitive dentin. They reported that it penetrated 20 μm into sound enamel. In dentin, reported penetration of F − was up to 50 to 100 μm and Ag + went deeper than that, getting close to the pulp chamber. They warned that because the agent stains the decalcified soft dentin black, its application should be confined to posterior teeth and gave specific instructions for its application.
Other similar products then became commercially available in other regions, like Silver Fluoride 40% in Australia (SCreighton Pharmaceuticals, Sydney), Argentina (SDF 38% several brands), and Brazil (several SDF concentrations and brands).
Since 2002, the search for innovative approaches to address the caries pandemic resulted in the publication of many clinical trials of SDF efficacy (through comparison with no treatment), and its comparative effectiveness with other chemopreventive agents (eg, fluoride varnish [FV]), as well as other treatment interventions (eg, atraumatic restorative treatment [ART]). The results of these studies established the effectiveness of SDF as a caries arresting agent. In 2014, the US Food and Drug Administration approved SDF as a device for dentin desensitization in adults and, in 2015, the first commercial product became available in the United States: Advantage Arrest. Advantage Arrest (Elevate Oral Care, LLC, West Palm Beach, FL) is a 38% SDF solution ( Box 1 ).
| Silver-Diamine Fluoride 38% | Professional tooth desensitizer |
| Desensitizing ingredient | Aqueous silver diamine fluoride, 38.3%–43.2% w/v |
| Presentation | Light-sensitive liquid with ammonia odor and blue coloring 8 mL dropper-vials contain: approximately 250 drops; enough to treat 125 sites; a site is defined as up to 5 teeth; the unit-dose ampule contains 0.1 mL per ampule |
| Specific gravity | 1.25 |
| Composition | 24%–27% silver 7.5%–11.0% ammonia 5%–6% fluoride (approximately 44,800 ppm) <1% blue coloring ≤62.5% deionized water |
Manufacturer’s instructions are limited to its approved use as a dentin desensitizer in adults. However, results from clinical trials conducted in many different countries on more than 3900 children have led investigators to develop recommendations for its use as a caries arrest medicament in children.
In 2017, the American Academy of Pediatric Dentistry published a Guideline for the “Use of Silver Diamine Fluoride for Dental Caries Management in Children and Adolescents, Including Those with Special Health Care Needs.” This document encouraged the off-label adoption of this therapy for caries arrest, much as FV is used for caries prevention. In November 2016, the US Food and Drug Administration granted SDF a breakthrough therapy status, which facilitates clinical trials of SDF for caries arrest to be carried out in the United States. Studies are currently underway that may result in the change of its labeling in the near future.
Since 2009, systematic reviews report on SDF’s ability to arrest or prevent caries lesions. For this article, we reviewed systematic reviews reported in English and published or accepted for publication through March 2018. We identified 6 systematic reviews that met most of the PRISMA guidelines. Their details can be found in Table 1 . The outcomes reported in these reviews include efficacy (ability to arrest or prevent caries lesions) and comparative effectiveness (eg, equivalence or superiority when compared with other modalities such as ART and FV). Included reviews report on the primary and permanent dentitions of children and the permanent teeth on elderly populations. We consider each endpoint separately herein.
| Author, Year | Outcome Measures | Studies Included and Max Follow-up Time Analyzed a | Dentitions Included/Frequency of SDF Application b | Results | |
|---|---|---|---|---|---|
| Rosenblatt et al, 2009 | Caries arrest and caries prevention | Systematic review only | SDF prevented fraction: caries arrest = 96.1%; caries prevention = 70.3% | ||
| Chu, 2002 | 30 mo | Primary max ant/q 12 mo | |||
| Llodra, 2005 | 36 mo | Primary post teeth and First permanent molars/q 6 mo | |||
| Horst et al, 2016 | Caries arrest and/or prevention | Systematic review only | Descriptive for each of the studies | ||
| Chu, 2002 | 30 mo | Primary max ant/q 12 mo | |||
| Llodra, 2005 | 36 mo | Primary post teeth and First permanent molars/q 6 mo | |||
| Zhi, 2012 | 24 mo | Primary ant and post/q 6 and q 12 mo | |||
| Yee, 2009 | 24 mo | Primary ant and post/1 app only | |||
| Liu, 2012 | 24 mo | Permanent first molars/q 12 mo | |||
| Monse, 2012 | 18 mo | Permanent first molars/1 app only | |||
| Dos Santos, 2014 | 12 mo | Primary ant and post/1 app only | |||
| Zhang, 2013 | 24 mo | Root caries on elders/q 12 and q 24 mo | |||
| Tan, 2010 | 36 mo | Root caries on elders/q 12 mo | |||
| Gao et al, 2016 | Caries arrest in children | Metaanalysis included only SDF 38% at different time periods | Caries arrest rate of SDF 38% was 86% at 6 mo 81% at 12 mo 78% at 18 mo 71% at 30 mo or > Overall arrest was 81% (95% CI, 68%–89%; P <.001) |
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| Chu, 2002 | 30 mo | Primary max ant/q 12 mo | |||
| Llodra, 2005 | 36 mo | Primary post teeth and First permanent molars/q 6 mo | |||
| Zhi, 2012 | 24 mo | Primary ant and post/q 6 and q 12 mo | |||
| Yee, 2009 | 24 mo | Primary ant and post/1 app only | |||
| Wang, 1964 Chinese | 18 mo | Primary ant and post/q 3 and q 4 mo | |||
| Yang, 2002 Chinese | 6 mo | Primary teeth/1 app only | |||
| Ye, 1994 Chinese | 12 mo | Primary teeth/1 app only | |||
| Fukumoto, 1997 Japanese | 48 mo | Primary teeth/1app only | |||
| Chibinski et al, 2017 | Control of caries progression in children after 12 mo follow-up | Metaanalysis included only studies with “low risk” of bias Evaluated at 12 mo results only (regardless of follow-up time) |
Caries arrest was 89% higher than using active materials/placebo at 12 mo | ||
| SDF vs control materials | |||||
| Duangthip, 2016 | 12 mo | Primary ant and post/1 app/year or 3 app weekly at baseline | |||
| Zhi, 2012 | 24 mo | Primary ant and post/q 6 and q 12 mo | |||
| NSP or SDF vs placebo | |||||
| Dos Santos, 2014 | Primary ant and post/1 app only | ||||
| NSP | 12 mo | ||||
| Seberol and Okte, 2013 | Primary max ants only/1 app only | ||||
| SDF (unpublished) | 12 mo | ||||
| Oliveira et al, 2018 | Prevention of new caries lesions in primary teeth | Metaanalysis included comparable studies evaluated at ≥24 mo | SDF applications reduce development of dentin lesions in treated and untreated primary teeth PF: 77.5%; 95% CI, 67.8%–87.2% |
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| SDF vs placebo | |||||
| Chu, 2002 | 30 mo | Primary max ant/q 12 mo | |||
| Llodra, 2005 | 36 mo | Primary post teeth and First permanent molars/q 6 mo | |||
| SDF vs GIC | |||||
| Dos Santos, 2012 | 12 mo | Primary ant and post/1 app only | |||
| Hendre et al, 2017 | Caries arrest and prevention in older adults | Systematic review only |
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| Tan, 2010 n = 203 |
36 mo | Root caries on elders/q 12 mo | |||
| Zhang, 2013 n = 227 |
24 mo | Root caries on elders/q 12 and q 24 mo | |||
| Li, 2016 n = 67 |
30 mo | Root caries on elders/q 12 and q 24 mo | |||
a Number of subjects in published studies for SDF in children are included in Table 2 n = listed in this table corresponds with the number of subjects in the study quoted not included in Table 2 .
Current evidence on the efficacy of silver diamine fluoride for caries arrest and prevention
In this section, we evaluate the results for SDF’s efficacy for caries arrest as reported by the systematic reviews and metaanalysis included in Table 1 . These systematic reviews used different perspectives to evaluate 17 prospective, parallel design, randomized, controlled clinical trials with a clearly defined outcome. As a result, and apparent from Table 1 , many of the systematic reviews included refer to the same body of clinical trials, just updating results as additional studies became available. Details of each of the included clinical trials conducted on children and published in English are included in Table 2 .
| Chu et al, 2002 | Yee et al, 2009 | Zhi et al, 2012 | Dos Santos et al, 2012 | Duangthip et al, 2018 | Fung et al, 2018 | Llodra et al, 2005 | Braga et al, 2009 | Liu et al, 2012 | Monse et al, 2012 | |
|---|---|---|---|---|---|---|---|---|---|---|
| Location | China | Nepal | China | Brazil | Hong Kong | China | Cuba | Brazil | China | Philippines |
| Dentition studied | Primary anterior only | Primary | Primary anterior and posterior | Primary | Primary anterior and posterior | Primary anterior and posterior | Primary cuspids, molars and permanent first molars | Permanent first molars | Permanent first molars | Permanent first molars |
| Caries effect studied | Arrest | Arrest | Arrest | Arrest | Arrest | Arrest | Arrest and prevention | Arrest | Prevention | Prevention |
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| SDF Clinical Application Protocol |
a No caries removal a One drop of SDF applied for 2 min to carious surfaces and dried with cotton pellet a No food or drink for 1 h after |
a Minor excavation a Does not specify SDF amount used or time of exposure a No food or drink for 30 min after |
a No caries removal a Does not specify SDF amount used a Cotton roll isolation, petroleum jelly on gingiva, SDF applied for 3 min and rinse and spit a No food or drink for 1 h |
a No caries removal a Does not specify SDF amount used or kind of isolation a SDF rubbed for 10 s
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a Does not specify SDF amount used, time of exposure, or kind of isolation | a Minor decay excavation on permanent molars only a Does not specify SDF amount used a Cotton roll isolation, SDF applied for 3 min and wash for 30 s |
a No caries removal a Does not specify SDF amount used a Cotton roll isolation and petroleum jelly on gingiva, SDF applied for 3 min, and wash for 30 s a No food or drink for 1 h |
a Does not specify SDF amount used, time of exposure, or whether it was rinsed or not a Cotton roll isolation a No food or drink for 30 min |
a Does not specify SDF amount used, SDF rubbed for 1 min followed by tannic acid, dried with cotton pellet, and covered with petroleum jelly a Cotton roll isolation |
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| Adverse effects | None | None | None | None | None | None | 0.1% Gingival irritation | None | None | None |
| Duration of study (mo) | 30 | 24 | 24 | 12 | 30 | 30 | 36 | 30 | 24 | 18 |
| Baseline caries | 3.92 dmfs (active anterior lesions) | 6.8 dmfs (active lesions) | 5.1 dmft (3 random teeth/child) | 3.8 dmft | 4.4 dmft 6.7 dmfs |
3.84 dmft 5.15 dmfs |
3.2 dmft | Noncavitated molar occlusal | No cavitated lesions | At least 1 sound permanent molar |
| Background F exposure | Low F exposure reported use of F toothpaste | Low F exposure Provided F toothpaste |
Low F exposure low access to F toothpaste | Low F exposure access to F toothpaste | F water F toothpaste |
Low F exposure F toothpaste |
Low F exposure + 0.2% NaF rinse in school every other week |
Low F exposure Provided F toothpaste |
Low F exposure Provided F toothpaste |
Low F exposure Provided F toothpaste |
| No. of subjects at baseline | 375 | 976 | 212 | 91 | 371 b | 888 | 425 | 22 children, 66 molars | 501 | 1016 |
| No. of subjects at endpoint | 308 | 634 | 181 | ? | 309 b | 799 | 373 | ? | 485 | 704 |
| Examinations after baseline | ×6 mo | 1, 12, and 24 mo | ×6 mo | ×6 mo | ×6 mo | ×6 mo | ×6 mo | 3, 6, 12, 18 and 30 mo plus radiographs at 6, 12 and 30 mo | ×6 mo | 18 mo |
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