Silver Diamine Fluoride (SDF) in Wellington: A Painless Way to Stop Tooth Decay — Even at Home

tiayuzh
Aug 18
5 min read

If you've had a check-up with recently, you may have heard your clinician mention "SDF." It's becoming one of the most talked-about tools in modern dentistry — and for good reason. Silver Diamine Fluoride (SDF) is a simple liquid that can stop tooth decay from getting worse, without a needle or a drill. Here's everything you need to know about it.

SDF is a painless way to stop tooth decay from progressing.

What Is SDF?

SDF is a clear-to-blue-tinted liquid that your dentist or oral health therapist paints directly onto a decayed tooth. It contains three key ingredients:

Silver – fights the bacteria that cause decay
Fluoride – helps strengthen and remineralise the tooth
Ammonia – keeps the solution stable

Together, these ingredients work as a team. The silver stops the bacteria in their tracks, while the fluoride helps rebuild the tooth's mineral structure. The result is a hardened, arrested area of decay that is no longer actively breaking down.

Applying SDF takes only a couple of minutes, and it doesn't require any numbing, drilling, or removal of decayed tissue in most cases — which is exactly why it has become so valuable for young children, anxious patients, older adults, and anyone who finds traditional dental treatment difficult to tolerate.

A Bit of History

SDF isn't actually new — it's simply new to the spotlight. It was first developed in Japan in the 1960s by Professor Reiichi Yamaga, who combined silver and fluoride to create a treatment that could be "painted on" to manage decay in children during a time when there weren't enough dentists to treat everyone. It was used widely across Japan through the 1970s, then fell out of favour there once modern fillings became more accessible.

Interest in SDF picked back up internationally in the 2000s, when researchers in places like Australia, the United States, and Hong Kong began publishing strong clinical evidence supporting its use. In 2014, SDF received clearance from the U.S. Food and Drug Administration, and by 2016 it had even been given "breakthrough therapy" status for its ability to arrest cavities. In 2021, the World Health Organization added SDF to its List of Essential Medicines for the management of dental caries. Today, it's used around the world, including right here in Aotearoa New Zealand, where it's approved by Medsafe for use by registered oral health practitioners.

The Research Behind It

SDF is one of the most well-studied preventive treatments in modern dentistry. Numerous clinical trials and systematic reviews have shown that SDF is highly effective at halting the progression of decay, particularly in primary (baby) teeth and in root surface decay in older adults. Compared with doing nothing, SDF significantly increases the chance that a decayed tooth will stop getting worse — and applying it twice rather than once further improves that success rate. Because of this strong evidence base, SDF now features in clinical guidelines from dental associations across the world, including the guidance developed for use here in New Zealand.

How Does It Work, Practically Speaking?

During your appointment:

The tooth is cleaned of loose debris.
A tiny drop of SDF is applied with a small brush directly to the area of decay.
It's left to absorb for about a minute (up to three minutes ideally).
Any excess is wiped or dried away.
You're asked not to eat or drink for about an hour afterwards.

That's it — no injections, no drilling, no discomfort. Depending on the tooth, your clinician may recommend covering the treated area with a tooth-coloured filling afterwards, either on the same day or at a later visit, to further protect it and improve appearance.

The Pros

No needles, no drilling – ideal for young children, people with dental anxiety, and those with medical conditions that make traditional treatment more complex
Fast and simple – treatment typically takes only a couple of minutes per tooth
Highly effective – strong evidence shows it stops or slows the progression of decay
Reduces pain and sensitivity – including for people with sensitive teeth or hypomineralised enamel (like Molar Incisor Hypomineralisation, or MIH)
Can delay or avoid more invasive treatment – such as extractions or treatment under sedation/general anaesthesia
Affordable – generally a lower-cost option compared with restorative treatment

The Cons

Permanent black staining – this is the main downside. Treated decay turns dark brown to black, and this staining does not come off (unless the area is later restored with a filling). This is actually a sign the treatment is working, but it means SDF is often reserved for back teeth or less visible areas, or discussed carefully with patients before use on front teeth.
Possible staining of white-spot lesions or immature enamel – SDF can occasionally stain areas that don't look visibly decayed if the enamel is porous or still developing.
Temporary staining of gums or skin – if SDF accidentally touches soft tissue, it can leave a brown mark that fades within one to three weeks. It is not harmful.
Bitter or metallic taste – some people notice this briefly after treatment.
Not a substitute for good oral hygiene – SDF works best as part of a broader plan that includes brushing, reduced sugar intake, and regular dental visits.
Not suitable for everyone – it isn't used on teeth with exposed nerves, active infection, or significant pain, and it's avoided in people with allergies to silver, fluoride, or ammonia.

Treated tooth surface permanently becomes black.

When Is SDF Recommended?

Your clinician might suggest SDF when:

A child has early decay and isn't yet able to sit through traditional dental treatment
Decay is present in hard-to-reach areas, or in patients who find it difficult to tolerate lengthy procedures (including some medically or physically compromised patients)
An older adult has root surface decay, which is common as gums recede with age
A tooth is sensitive and other desensitising treatments haven't been effective
Someone has Molar Incisor Hypomineralisation (MIH) causing sensitivity in the back teeth
The goal is to "buy time" — slowing decay while a longer-term treatment plan is arranged
Traditional treatment would otherwise mean sedation or general anaesthesia, and a lower-risk option is preferred first

SDF isn't meant to replace fillings, crowns, or good home care — think of it as a powerful tool in the toolbox, used at the right time, for the right tooth, for the right patient. Your dentist will always explain your options, including the pros, cons, and alternatives, so you can make the choice that's right for you or your child.

Have Questions?

Every mouth is different, and whether SDF is a good option for you depends on your specific teeth, your health history, and your preferences. If you'd like to know whether SDF could help you or your child, come and chat with our team at Wholesome Smiles — we're always happy to talk through your options.

This article is for general information only and does not replace personalised advice from your dental professional. If you have concerns about tooth decay or sensitivity, please book an appointment with our team.