Rella Christensen, PhD, discusses the use of silver diamine fluoride for trauma-free caries treatment.
Q: Who needs to know about silver diamine fluoride (SDF), and why?
A: Anyone who cares for the health of people of any age needs to become acquainted with SDF (eg, dental/medical clinicians, school nurses, daycare for children and adults, social workers) because (1) US clinicians are using SDF for caries patients of all ages to prevent pain, delay progression, and lower biofilm accumulation. SDF needs no injection, handpiece, or dentist (it can generally be applied by personnel who apply fluoride); (2) published randomized controlled clinical trials report caries prevention using one annual application of SDF is superior to fluoride varnish using 4 annual applications—for children and elders; (3) SDF can improve caries treatment outcomes in difficult access areas (ie, furcations); (4) SDF hardens soft dentin and enamel and desensitizes, making subsequent restorative procedures easier for the dentist and patient; (5) slowing caries progression with SDF buys time for patients struggling to modify poor habits involving diet, oral hygiene, saliva flow, and dental treatment fear; and (6) offices not offering SDF may find some patients going elsewhere to receive it.
Q: Has SDF always been available, or is it new?
A: SDF is relatively new to the United States (FDA clearance, 2014; commercial product, 2015; CDT code D1354, 2016), but it was used extensively in Japan for 80-plus years for caries arrest. It was brought to the United States by dentists seeking trauma-free, inexpensive ways to stop or delay dental caries in children and vulnerable populations.
Q: How does SDF arrest dental caries?
A: SDF kills microbes and hardens damaged tooth structure. SDF sold in the United States (brand name: Advantage Arrest) is composed of 25% silver, 8% ammonia, 5% fluoride, and 62% water. Antimicrobial activity comes mostly from the silver ions and tooth mineralization from the high concentration of fluoride ions. Ammonia is present mainly to stabilize the solution by holding ions in suspension, but it also temporarily raises pH in local areas. Numerous SDF clinical applications and chemistry were defined 45 years ago by Japanese researchers (Yamaga R, Nishino M, Yoshida S, et al. J Osaka Univ Dent Sch. 1972;12:1-20).
Q: Are there disadvantages to SDF?
A: The most obvious disadvantage is, once dried, it leaves a permanent brown-black stain on demineralized tooth structure, fabrics, and clinical furnishings, and a transient black stain on oral soft tissues and skin. Patients and/or guardians need to be informed. The manufacturer (Elevate Oral Care) suggests using an informed consent that contains photographs of treated teeth. Although some clinicians feel strongly that caries arrest is far more important than oral aesthetics, this is a decision for each patient and/or guardian. Critical points in informed consent include communicating treatment options along with the advantages and disadvantages, risks, and costs of each, and what will happen if no treatment is performed. Stain can be covered subsequently with tooth-colored resin-modified glass ionomer, glass ionomer, or resin restorative material. Another option is use of potassium iodide saturated solution immediately after SDF application to lighten the stain. Other disadvantages include unpleasant odor and taste, and can be minimized by placing a small amount of toothpaste on an untreated tooth. Data are lacking on longevity of the treatment. TRAC Research’s very early microbial data indicate some microbes in deeper layers survive 3 SDF treatments performed at one-week intervals, indicating SDF may not be able to stop lesion progression, but instead delays progression. Also, others have reported that every lesion has not been stopped by SDF; in these cases, the dentin remains unstained and soft. However, even with this, clinical studies show SDF outperforms anything else currently used for the same purposes.
Q: What are some indications and contraindications of SDF?
A: As suggested by the University of California San Francisco Dental School Paradigm Shift Committee, indications are (1) extreme caries risk (particularly in very young or very old), (2) difficult management cases (behavior or medical problems), (3) difficult access treatment areas (furcations and margins), (4) more lesions than treatable in one visit, and (5) access to care problems (humanitarian and bedridden). Contraindications are: (1) silver allergy, (2) presence of open or sore areas on oral soft tissues, (3) if patient and/or guardian object to tooth discoloration in spite of possibility to cover later with tooth colored materials, and (4) pregnancy (if potassium iodide is planned to minimize dark stain).
Q: What are the clinical procedure steps?
A: Step 1—If possible, gently remove heavy biofilm with Starbrush (Ultradent Products) in low-speed handpiece and rinse. Step 2—Isolate and dry. Step 3—Place a small amount of SDF directly onto lesion(s) using smallest (black handle) Microbrush (Denbur). Precise placement avoids inadvertent staining. Step 4—Allow SDF to dry at least one minute (longer, if possible), then remove excess with cotton ball. (Optional step to minimize staining: apply saturated solution of potassium iodide using smallest Microbrush, wait 10 seconds, repeat until no white precipitate appears.) Step 5—Water rinse. Step 6—Repeat all steps 3 times at approximately one-week intervals.
Q: What is the future of SDF caries treatment?
A: SDF for caries arrest is an attempt to slow lesion progression and prevent pain while avoiding patient fear and lowering costs. SDF is meeting these goals in most patients of all ages. A nontooth-staining chemical would be preferred by most clinicians, but the stain has proven useful to accurately identify location of lesions. (SDF does not stain healthy tooth structure.) SDF use in the United States is gaining momentum, particularly with pediatric, public health, and humanitarian clinicians. If SDF replaces fluoride varnish, it will gain routine use in general dentistry throughout the United States, with the stain identifying caries missed by radiographs.
Dr. Christensen leads TRAC Research Laboratory at Clinicians Report Foundation. She can be reached via the email address rella@tracresearch.org.
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