Silver diamine fluoride in practice: indications, the 38% protocol, staining consent and pairing with fluoride varnish

The problem: six cavities and no cooperation

A three-year-old with multiple carious primary molars, a parent who cannot commit to a hospital general anaesthetic, and a child who will not open for a handpiece. Or an eighty-year-old with root caries on every remaining tooth and a heart that makes long appointments unwise. Silver diamine fluoride was made for these patients: a drop of liquid, no drilling, no injection, and an active lesion that stops progressing. The price is a black stain that must be explained before, not after. This guide covers the indications, the protocol, the consent conversation, and how SDF pairs with varnish, sealants and crowns in our catalogue.

Understand: what SDF does

Silver diamine fluoride is a clear, alkaline solution of silver, fluoride and ammonia. On a carious lesion the silver ions kill the bacteria in the biofilm and the dentine and precipitate as silver phosphate and silver protein complexes; the fluoride forms fluorapatite and hardens the remaining dentine; the ammonia keeps the solution stable. The lesion stops, hardens, and turns black where the silver has precipitated in the demineralised tissue. Sound enamel does not stain because there is nothing for the silver to bind to.

What the evidence says

• Evidence. A systematic review of paediatric trials found 38% silver diamine fluoride effective at arresting caries in primary teeth, with the 38% concentration outperforming lower concentrations and arrest rates above those of fluoride varnish.¹
• Guideline. Professional bodies describe SDF as an option for children who are very young, anxious or have special needs, and in general recommend re-application at intervals; six months is the most cited interval, with some protocols applying a second dose within the first weeks for active lesions.^{2, 3}
• Evidence. In a 2024 randomised trial of 84 children with 505 lesions, two applications of 38% SDF with fluoride varnish given one month or four months apart arrested 98% and 96% of lesions, against 72% when given six months apart; the authors note the groups differed in lesion numbers and follow-up length.⁵
• Evidence. The main adverse effect in trials is the permanent black staining of the arrested lesion; transient gingival irritation is reported where the solution touches soft tissue.¹
• Practice. Written informed consent that names the staining is treated as mandatory in every protocol we reviewed.

Key numbers, labelled

• Manufacturer. The stocked products are 38% silver diamine fluoride; one drop treats several surfaces, and the bottle is used with a micro applicator, not a syringe.⁴
• Manufacturer. Application time is short, commonly about one minute of contact, followed by air drying and a period without rinsing or eating per the instructions.⁴
• Practice. Clinicians give the second application within one to four months, then re-assess at each recall and re-apply to any lesion that is not hard and black, and cover arrested lesions with glass ionomer or a crown when aesthetics or function require it.

Indications and contraindications

Use SDF for	Do not use SDF for
Active cavitated lesions in primary teeth of children who cannot tolerate conventional treatment	Lesions with signs of pulpal involvement: spontaneous pain, swelling, sinus, abscess, or a radiolucency
Stabilising many lesions before staged restorative treatment	Patients with a known silver allergy
Root caries in older or medically compromised adults	Patients or parents who decline the staining after a clear explanation
Hypersensitive teeth and exposed root surfaces	Ulcerated or inflamed soft tissue near the lesion
Lesions under a planned stainless steel crown or glass ionomer restoration	Anterior lesions in a patient for whom the stain is unacceptable and restoration is possible

The protocol

1. Diagnose and photograph. Confirm the lesion is active and the pulp is symptom-free. Take a photograph for the record and for the consent discussion.
2. Consent. Explain the staining with a picture, say it is permanent on the lesion, say sound enamel does not stain, offer the alternatives. Written consent, signed, in the record with the tooth numbers.
3. Protect. Petroleum jelly on the gingiva and lips; safety glasses on the patient and the operator; a bib and gloves, because SDF stains skin, clothes and worktops.
4. Prepare. Cotton-roll isolation, remove gross debris with a brush or a spoon without deliberate excavation, dry the lesion with air.
5. Apply. One drop in a dappen dish. A super-fine micro applicator, bent to reach, saturated and blotted so it does not drip. Apply to the lesion only for the manufacturer's contact time.
6. Dry and wait. Gentle air; keep saliva off for the stated time; no rinsing, eating or drinking for the period in the instructions.
7. Optional potassium iodide. Reduces the stain when applied immediately; may reduce arrest. Decide per case, and say so in the consent.
8. Record. Teeth, surfaces, product, batch, consent, and the review date.
9. Second application at one to four months, then review at each recall. Arrested lesions are hard, black and shiny; re-apply to anything soft or brown. Plan glass ionomer coverage or a crown where needed.

Options: SDF and the materials around it

Class	Stocked examples	Role
Silver diamine fluoride 38%	Advantage Arrest (Elevate Oral Care), Med Protect SDF 38%	Arresting active lesions
Sodium fluoride varnish 5%	CharmVarnish, NovaBright, Enamelast, FluoriMax 2.5%	Prevention on the rest of the dentition at the same visit
APF gel and trays	Gelato APF gel, fluoride trays	Professional fluoride application in older children and adults
Micro applicators	Bendable disposable micro applicators, super fine	Precise placement of a small volume
Glass ionomer and stainless steel crowns	Glass ionomer restoratives; primary molar crowns by tooth code	Covering arrested lesions where aesthetics or function need it

Compare: SDF, varnish and sealant by indication

Indication	SDF 38%	Fluoride varnish 5%	Sealant
Active cavitated lesion, primary tooth	First choice for arrest	Prevention only; weaker arrest	No
Non-cavitated early lesion	Option where staining is acceptable	Yes, with diet advice	Yes on occlusal fissures
Caries prevention, high-risk child	No (nothing to arrest)	Yes, at each recall	Yes on erupted molars
Root caries, older adult	Yes	Yes as adjunct	No
Hypersensitivity	Yes	Yes	No
Aesthetic zone, restoration possible	Usually no	Adjunct	Not applicable

Recommended products

Silver diamine fluoride and the applicators that place it:

Fluoride varnishes for the rest of the mouth at the same visit:

Buying advice

One 5 ml bottle of 38% SDF treats a large number of lesions; buy it with a box of super-fine micro applicators and a fluoride varnish in single doses so the prevention half of the visit is as quick as the arrest half. Write the consent form before the first patient, not after.