Silver diamine fluoride (SDF) is a liquid a dentist can brush onto a cavity to stop the decay from spreading, without drilling, injections, or filling. That makes it a useful option for young children, anxious patients, and people who find dental treatment difficult. Studies of the standard 38 percent solution report that around 81 percent of treated lesions are arrested, which is why interest in it has grown.
Key takeaways
- SDF is a liquid that stops (arrests) tooth decay rather than removing it.
- It is painless to apply, needs no drilling or anaesthetic, and takes about a minute per tooth.
- Meta-analyses of 38 percent SDF report roughly 81 percent of lesions arrested, with the best results when applied about twice a year.
- The main downside is that the arrested decay turns permanently black.
- It is especially useful for very young children, special-needs patients, and holding a tooth until fuller treatment is possible.
What silver diamine fluoride is
SDF combines silver, which has antibacterial properties, with fluoride, which helps harden the tooth surface. Painted onto a cavity, it kills the bacteria driving the decay and helps the remaining tooth structure resist further breakdown. It does not rebuild lost tooth, and it does not remove the decay. Instead it stops an active cavity in its tracks, buying time and often avoiding more invasive treatment in a young child.
Because it needs no drill and no needle, application is quick and comfortable. The dentist isolates the tooth, dries it, and brushes on a small amount. This is why it fits so well alongside other gentle preventive measures such as fluoride varnish for children and dental sealants.
How well does SDF work?
The evidence is encouraging. A meta-analysis of studies using 38 percent SDF found an overall proportion of arrested caries of about 81 percent, and the highest arrest rates (up to around 89 percent) were seen when it was applied roughly every six months. Regular reapplication matters, because a single application is less reliable than an ongoing schedule.
| Feature | SDF | Traditional filling |
|---|---|---|
| Drilling needed | No | Yes |
| Anaesthetic (needle) | No | Often |
| Removes decay | No, stops it | Yes |
| Appearance of treated area | Turns black | Tooth-coloured or metal |
| Best suited to | Young or anxious patients, holding a tooth | Restoring shape and function |
The black staining trade-off
The one consistent downside is appearance. When SDF arrests decay, the treated area turns permanently black. On a baby back tooth this is often a reasonable trade for avoiding a distressing procedure, and the tooth will eventually fall out anyway. On a visible front tooth, or in an older child or adult who is conscious of it, the staining may be a deciding factor against it. There are no other significant adverse effects reported beyond the staining, which is well documented in the research. Weighing the look against avoiding the drill is a conversation to have with your dentist.
Who SDF suits best
SDF is particularly valuable for very young children with early decay who cannot yet cope with fillings, children with a lot of decay where treating everything at once would be overwhelming, patients with additional needs for whom conventional treatment is difficult, and situations where a tooth needs to be held stable until fuller care is possible. It is a tool for managing decay, not a replacement for good daily habits. Our guides on early childhood tooth decay and how much fluoride toothpaste children need cover the prevention side.
Frequently asked questions
Does SDF hurt?
No. It is brushed on and there is no drilling or injection. Most children tolerate it very well.
Why does the tooth go black?
The silver in SDF reacts with the arrested decay and darkens it. Only the decayed part stains, but on a visible tooth this can be noticeable, and it is permanent unless the area is later filled or covered.
How often does SDF need reapplying?
Applying it about twice a year is linked to the best arrest rates. Your dentist will advise a schedule and review the teeth over time.
Can adults have SDF too?
Yes. It can be useful for adults, for example to manage root-surface decay or to stabilise a tooth, though the staining is often a bigger concern for adults.
Is SDF covered for children in Australia?
Coverage depends on the scheme and your circumstances. Eligible children may access some dental care through the Child Dental Benefits Schedule, which we explain in our CDBS guide.
The takeaway
Silver diamine fluoride is a simple, painless way to stop decay in its tracks, and it is a genuine help for young and anxious patients. Its effectiveness is well supported, with roughly 81 percent of lesions arrested in studies of the 38 percent solution. The trade-off is permanent black staining of the treated decay, which makes it better suited to some teeth than others. Whether it suits your child is best decided with your dentist. The team at Lumi Dental can talk it through, and current offers are on the current deals page.
This article is general information and not a substitute for personalised advice from your dentist.
