Silver diamine fluoride, or SDF, has become a hot topic in preventative and caries management dentistry within the last decade. Being a newer product, many questions about its history and usage as both a preventative and caries-management tool have yet to be explained.

This article addresses the history of using silver-based products for caries management and how silver diamine fluoride is being utilized to prevent caries and arrest the progression of active carious lesions.

History of caries prevention

Dental caries has been a human problem for millennia. The first known use of mitigating dental decay though caries prevention can be seen centuries ago in Asia, where the concept of “tooth darkening” was introduced.

This treatment utilized different solutions to stain and darken the teeth to a jet-black appearance. In Japan, the “ohaguro” concept of staining teeth was seen as a form of beauty. A secondary effect of this staining was that the teeth became resistant to dental decay.

Years later, medicaments designed specifically to prevent tooth decay were applied to teeth by dental professionals. In the Americas, silver nitrate was utilized in the early 1900s to help conservatively arrest and manage dental caries.

Solutions such as silver nitrate were utilized to arrest carious lesions in patients who presented with substantial dental decay. However, with the advent of local anesthetics and new materials for dental restorations, most of these conservative caries management treatment options decreased in popularity.

In 2014, the FDA approved silver diamine fluoride (SDF) to be utilized as a desensitizing agent in the United States. Although SDF has been approved for use as a desensitizing agent, it has been effectively used off-label for its caries prevention and caries-arresting properties.

Most of the products on the market today are composed of 38% SDF in solution. Silver diamine fluoride is a liquid solution with a pH of approximately 10 that is composed of silver, fluoride, and ammonia particles. It can be applied to both primary and permanent teeth to aid in caries prevention and caries management.

SDF for caries prevention

Silver diamine fluoride is a useful tool to aid in the prevention of dental caries. Laboratory studies performed on extracted teeth have found that biofilms were not able to form on teeth that were treated with SDF. Additionally, SDF kills the bacteria that lead to dental caries.

One unique advantage of SDF is that its preventative effect is widespread in the oral cavity. Even when SDF is applied to only a single tooth, the preventative effect is experienced on the adjacent teeth. This antimicrobial effect is profound, leading to a “zombie effect” in which bacteria killed after being exposed to SDF can contribute to killing of other active cariogenic bacteria in the mouth.

SDF is especially advantageous for caries prevention in populations that may be more susceptible to developing decay. Studies have shown that one annual application of SDF has a greater preventative effect than repeated applications of other preventative medicaments, such as topical fluoride.

SDF for arresting caries

Recently, SDF has gain popularity as a conservative method for arresting active carious lesions. Current research on SDF has shown it is extremely effectively at arresting active lesions. In a study investigating the effectiveness of arresting root caries on elderly patients, 90% of carious lesions were arrested after a single application of SDF.

SDF can be a useful tool for conservative management of dental caries in certain clinical scenarios. Patients who have limited access to dental care, have medical or behavioral concerns that make traditional operative dentistry an extreme challenge, and patients who have rampant dental caries can benefit from utilization of silver diamine fluoride.

Rampant dental caries. SDF is one option for helping with caries control.
Figure 1: Rampant dental caries. SDF is one option for helping with caries control.

After SDF has been applied, the solution starts to kill the bacteria that has caused the carious lesion. Over the course of a few weeks, the initial lesion will harden due to remineralization of the tooth structure.

As this occurs, the carious lesion will become darker and eventually become jet-black. The dentin in this dark, arrested carious lesion has been shown to be more resistant to attack from carious bacteria than sound, unaffected dentin.

Since this dark lesion may present as an esthetic dilemma, it is advised to inform patients of the staining that SDF can cause and to have an informed consent form reviewed by the patient or their guardian prior to application of SDF.

Before SDF – a freshly extracted tooth with dental caries.
Figure 2: Before SDF – a freshly extracted tooth with dental caries.
After SDF application.
Figure 3: After SDF application.

Teeth that are treated with SDF can still be restored. Both total-etch and self-etch methods have proven to be effective in bonding composite to non-carious dentin that has been treated with SDF. Glass ionomers can also be effectively placed on teeth treated with SDF.

Disadvantages and side effects

The main disadvantage of SDF is its tendency to stain active carious lesions. Healthy, unaffected enamel and dentin are resistant to staining from SDF. However dentin with carious bacteria will stain jet-black after being exposed to SDF.

To reduce this dark staining, a saturated potassium iodide solution can be applied. This solution will bind to excess silver particles and theoretically can reduce the level of staining. However, initial research has shown that minimal reduction of staining occurs after the application of potassium iodide.

The staining caused by SDF will also occur on gloves, tabletops, clothing, or any other surface that SDF comes in to contact with. Care must be taken to protect surfaces and the patient’s clothing to avoid accidentally staining these areas.

Since SDF contains silver particles, some patients report a metallic taste during the application. This is typically transient and will dissipate shortly after the treatment is completed.

SDF should not be applied if a patient is known to have an allergy to silver. SDF can also irritate the gingiva. As a result, it is contraindicated in patients with mucositis or desquamating gingivitis.

Gingival irritation after application of SDF.
Figure 4: Gingival irritation after application of SDF.

Application protocol

The maximum dosage of SDF is one drop of liquid for every 10 kg of the patient’s weight. This maximum dosage should never be exceeded. One drop of SDF can be effectively applied to up to five teeth.

Various protocols for application of SDF exist. The protocol below is based off some of the most current strategies for caries management using SDF:

  • Isolate the area using cotton rolls and/or gauze.
  • If near the gingiva, consider applying a layer of petroleum jelly to protect the gingiva from irritation.
  • Dry the area that SDF will be applied.
  • Using a microbrush, apply SDF to the affected area. Allow the solution to remain on the tooth for one minute.
  • Remove excess SDF solution with a cotton roll.
  • Rinse area with water.

Repeating applications multiple times per year is advised to maximize the prevention and caries arresting effects of SDF.

Conclusions

SDF is a newer product that can help aid in the caries management process. It is especially useful for patients who are at a high caries risk and for patients who may have limitations that prevent them from performing adequate oral hygiene, home care, or undergoing traditional restorative dentistry procedures.

While it is not a panacea for preventing and managing dental caries, SDF is a useful tool that when applied in the proper clinical situations can help our patients with the prevention and management of their dental decay.

Andy Janiga, D.M.D., is a contributor to Spear Digest.

References:

  1. Horst, J.A., et al. “USCF protocol for caries arrest using silver diamine fluoride: Rationale, indications and consent.” CDA Journal 2016; 44: 17-27.
  2. Knight, G.M. et al. “Inability to form a biofilm of streptococcus mutans on silver fluoride – and potassium iodide – treated demineralized dentin.” Quintessence. Feb 2009; 40 (2): 155-161
  3. Mei, L.M., et al. “Clinical use of silver diamine fluoride in dental treatment.” Compend Contin Educ Dent Feb 2016; 37 (2): 93-98
  4. Horst, J.A. and Heima, M. “Prevention of dental caries by silver diamine fluoride.” Compendium eBook November 2020: 1-9
  5. Li, R., et al. “Randomized clinical trial on arresting dental root caries through silver diammine fluoride applications in community-dwelling elders.” J Dent 2016; 51: 15-20
  6. Quock, R.L. “Effect of silver diamine fluoride on microtensile bond strength to dentin.” Operative Dentistry. 2012: 37 (6): 610-616