Silver Diamine Fluoride: Stopping Cavities Without a Drill
Clinically reviewed by Dr. Abinaash Kaur, DDS, RCDSO, on 2026-08-14. Dr. Kaur is a general dentist in Toronto (Bloor West Village) registered with the Royal College of Dental Surgeons of Ontario.
There's a liquid a dentist can paint on a cavity in a baby tooth that stops the decay in about half of cases, with no drill and no needle. It also turns the treated spot permanently black, and that trade is the entire decision a parent has to make.
The liquid is silver diamine fluoride. It's been getting attention because a large trial finally put real numbers on it, and because the alternative for a frightened three-year-old with several cavities is often the operating room.
I've been treating families in Bloor West Village for about 25 years. The parents who ask me about this are rarely looking for a shortcut. They're looking for anything that isn't a general anaesthetic.
So here's what it does, how well it works, and where it falls short.
What is silver diamine fluoride?
Silver diamine fluoride is a liquid containing silver and fluoride that a dentist brushes onto an active cavity to stop it from getting worse. The silver acts on the bacteria and the exposed dentin, and the fluoride helps harden what's left of the tooth surface.
It takes about a minute per tooth. No freezing, no drilling, no removing tooth structure.
That last part is why it matters for small children. A two-year-old who can't sit still for twenty minutes with a rubber dam can usually manage one minute with a tiny brush.
Here's the important limit, and I'd rather say it early than bury it. Silver diamine fluoride arrests decay. It doesn't reverse it, it doesn't rebuild the tooth, and it doesn't fill the hole.
The cavity is still a hole. It's just a hole that has stopped growing. If you want the full picture on what can and can't be reversed, our post on whether a cavity can heal itself covers where the line sits.
How well does it work?
This is the part that changed recently. A phase III randomized, placebo-controlled trial published in JAMA Pediatrics in 2026 enrolled 830 generally healthy children aged 12 to 71 months who had severe early childhood caries and active cavitated lesions (JAMA Pediatrics via PubMed). Children got either 38% silver diamine fluoride or a placebo, applied at the start and again at 6 months (PubMed).
The results, in the trial's own numbers. Silver diamine fluoride arrested 57.5% of lesions at 3 months, 54.0% at 6 months, and 50.2% at 8 months, against placebo rates of 18.8%, 22.5%, and 17.4% (PubMed).
So roughly half the treated cavities stopped, against roughly one in five that stopped on their own.
Now read that same sentence the other way. About half the treated lesions were not arrested at 8 months, even after two applications (PubMed). That's the number most articles about this leave out, and it's the one that decides whether you still need a plan B.
Of the 830 children enrolled, 584 finished the study, and about 10% of those lost to follow-up were lost to COVID-19 (PubMed). These were children with a lot of decay: mean decayed, missing and filled teeth was 11.36 (PubMed).
Why does it turn the tooth black?
Silver. The same chemistry that stops the bacteria stains the decayed dentin, and the stain is dark, permanent, and shows up within days.
It marks the cavity, not the whole tooth. A small spot between two back teeth may be nearly invisible. A cavity across the front of an upper front tooth will look like a dark patch every time your child smiles.
Nobody warns parents about this properly, and then they're upset at the two-week check. Have no fear about asking to see photographs first. Any dentist offering this should be able to show you what treated teeth look like.
Would parents actually accept a black spot?
Most people assume the answer is a flat no. The research says it depends entirely on what you're comparing it to.
A survey of 120 parents at a New York pediatric dental clinic and several New Jersey private clinics asked exactly this (JADA via PubMed). On back teeth, 67.5% judged the staining aesthetically tolerable. On front teeth, only 29.7% did (PubMed).
Predictable so far. Then the researchers changed the question.
When parents were asked to decide in a scenario where the alternative was their child undergoing general anaesthesia, acceptance climbed to 68.5% for back teeth and 60.3% for front teeth (PubMed). The authors concluded that although staining on front teeth was undesirable, most parents preferred it to sedation or general anaesthesia (PubMed).
The black spot isn't the real question. What it's replacing is.
What are you really choosing between?
Here's the piece that reframes this whole topic for Canadian parents, and it comes from the Canadian Dental Association, not from anyone selling anything.
"Dental surgery for ECC under general anesthesia is the most common day surgery procedure at most pediatric hospitals in Canada" (Canadian Dental Association).
Read that again. Not tonsils. Teeth.
The rate of dental surgery for early childhood caries runs at 12.1 per 1,000 children nationally, and children in rural regions have rates 3.2 times higher than urban children, at 31.2 per 1,000 versus 9.8 (Frontiers in Public Health via PMC). In Manitoba alone, 18,544 children had dental surgery under general anaesthesia across a ten-year period, at a mean age of 3.28 years (J Can Dent Assoc via PubMed).
Three years old, in an operating room, for teeth.
That's the comparison silver diamine fluoride actually sits in for a lot of small children. Not "black spot versus perfect white filling." Often it's "black spot versus a hospital day, an anaesthetist, and a child who can't eat beforehand." Our guide to sedation and comfort options explains what the different levels involve.
Does it hurt, and is it safe?
The trial measured this directly, which is worth knowing.
There were no differences in pain between the silver diamine fluoride group and the placebo group (PubMed). Adverse events were reported by 47.3% of the treatment group and 43.3% of the placebo group, most of them mild to moderate (PubMed). Treatment-related adverse events were nearly identical between groups, at 22.9% versus 22.2%, and 4 events in the whole trial, 0.6%, were severe (PubMed).
It tastes metallic and it can leave a temporary mark on skin or gum tissue that fades. That's about the size of it.
Where does this sit right now?
Honest answer: it's newer than the headlines suggest, and it isn't a settled part of standard care everywhere.
The trial itself states its purpose was to evaluate silver diamine fluoride "to inform US Food and Drug Administration (FDA) regulatory approval" (PubMed). Its conclusion supports "its consideration for FDA drug approval" (PubMed). That's a treatment being used while the regulatory paperwork catches up, not one that's been formally approved for this purpose and sitting in every practice.
For comparison, the CDA's own position statement on early childhood caries lists the measures it names for managing the disease: optimizing home care, interim therapeutic restoration, more frequent dental visits with regimented applications of topical fluoride such as fluoride varnish, and full crown coverage, with behaviour guidance, sedation or general anaesthesia assessed according to the child's developmental level and the extent of disease (Canadian Dental Association).
So the practical move is simple. If you want this for your child, ask whether the office offers it before you book. Not every practice does, and a dentist who doesn't isn't withholding anything from you.
Which cavities is it right for?
It fits a specific situation rather than every cavity.
It suits a young child who can't yet cope with a filling, a child with more decay than can safely be treated in one visit, a tooth that's going to fall out in a couple of years anyway, and a family who needs to stop things getting worse while a fuller plan comes together.
It doesn't suit a tooth where the decay has reached the nerve, an abscessed tooth, or a front tooth where appearance matters a great deal to the family. It also doesn't remove the need to follow up, since arrest isn't permanent and reapplication is part of how it works.
One more thing worth saying plainly. Stopping a cavity isn't the same as fixing the reason it happened. If nothing changes, new cavities keep arriving on teeth that haven't been treated yet.
What still prevents most of this?
The unglamorous things, which is always the answer.
The CDA encourages a dental assessment of infants within 6 months of the first tooth appearing and no later than 12 months of age (Canadian Dental Association). That first visit is mostly a conversation and a look, and it's the cheapest thing in dentistry. Our parent guide to the first visit walks through what happens.
Statistics Canada's direct measurements for 2022 to 2024 found 17% of children aged 1 to 5 had at least one primary tooth affected by decay (Statistics Canada). Among children aged 6 to 11, more than half, 57%, had at least one affected tooth (Statistics Canada).
Fluoride toothpaste, a parent doing the brushing until a child can do it well themselves, and less time with sugary drinks in contact with teeth do most of the work here. Our posts on baby oral health and fluoride in Toronto's water cover both sides of that.
Some days the schedule pushes me, and a nervous small child still gets the time they need. A first visit that goes well is worth more than any product I could paint on later.
Frequently Asked Questions
Q: Does silver diamine fluoride really stop cavities? About half the time, which is far better than doing nothing. In a phase III randomized placebo-controlled trial of 830 children aged 12 to 71 months, 38% silver diamine fluoride arrested 57.5% of lesions at 3 months, 54.0% at 6 months and 50.2% at 8 months, against placebo rates of 18.8%, 22.5% and 17.4% (PubMed). It arrests decay rather than reversing it, so the cavity remains a hole that has stopped growing.
Q: Will it turn my child's tooth black? Yes, on the decayed part, and the stain is permanent. Parents judge that differently depending on which tooth it is: in a survey of 120 parents, 67.5% found staining on back teeth aesthetically tolerable but only 29.7% said the same about front teeth (PubMed). Ask to see photographs before agreeing to it, especially for a front tooth.
Q: Is it better than a filling? It's not better, it's different. A filling removes the decay and restores the tooth's shape and function; silver diamine fluoride stops the decay and leaves the hole. It earns its place when a child can't manage a filling yet, or when the realistic alternative is treatment under general anaesthesia, which is the most common day surgery procedure at most Canadian pediatric hospitals (Canadian Dental Association).
Q: Does it hurt? The trial found no differences in pain between children who received silver diamine fluoride and those who received placebo (PubMed). There's no needle and no drilling. It tastes metallic, and it can leave a temporary mark on gum tissue or skin that fades on its own.
Q: Is it safe? The safety profile in the trial looked much like placebo. Adverse events were reported by 47.3% of the treatment group and 43.3% of the placebo group, treatment-related events were 22.9% versus 22.2%, and just 4 events across the whole trial, 0.6%, were severe (PubMed). It's worth knowing that the trial was designed partly to inform FDA regulatory approval, so this is a treatment whose formal approval is still catching up to its use (PubMed).
Q: Can every dentist do this? No, and it's fair to ask before booking. It's a specific product and technique, so call and ask whether the office offers it. The CDA's position statement on early childhood caries names home care, interim therapeutic restoration, more frequent visits with topical fluoride, and full crown coverage among the standard measures, with sedation or general anaesthesia considered according to the child's developmental level and extent of disease (Canadian Dental Association).
Q: How do I stop my child needing any of this? Start early and keep it boring. The CDA encourages a dental assessment within 6 months of the first tooth and no later than 12 months of age (Canadian Dental Association). Statistics Canada's 2022 to 2024 measurements found 17% of children aged 1 to 5 already had at least one primary tooth affected by decay (Statistics Canada), so early is earlier than most parents expect.
Reviewed by Dr. Abinaash Kaur, B.Sc., DDS (University of Toronto Faculty of Dentistry), who has practised general and family dentistry in Bloor West Village for about 25 years. This article is general oral health information, not a diagnosis or a substitute for an examination of your child.
Worried about a spot on your child's tooth, or dreading the idea of treatment under anaesthetic? Bring them in and we'll look, explain what we see in plain words, and go through the options together. We're at 750 Annette Street in Bloor West Village, serving the Junction, High Park, and Baby Point. Book a visit with The Village Dentist and we'll take it from there.
