Authors: Helen V Worthington, Sharon Lewis, Anne-Marie Glenny, Shulamite Huang, Nicola Innes, Lucy O'Malley, Philip Riley, Tanya Walsh, May Wong, Jan Clarkson, Analia Veitz-Keenan

Is silver diamine fluoride varnish an effective treatment for preventing and managing tooth decay in children and adults?*

Key messages

‐ We can't tell if silver diamine fluoride (SDF) is better than no treatment at preventing or treating tooth decay.

‐ We can't tell if SDF is better or worse than other treatments at preventing or treating tooth decay.

‐ New studies could help to find out about the unwanted effects of SDF, whether people are bothered by the staining on the teeth caused by SDF, and the best treatment approach.

What is tooth decay?

Tooth decay happens when bacteria in your mouth break down sugars from food, producing acids that damage tooth enamel (hard surfaces). This can lead to holes, or cavities, in the teeth. Tooth decay affects the crown of the tooth (the part above the gum) of baby teeth, and the crown and root of permanent teeth. If it is not prevented or treated it can cause toothache, infections and tooth loss.

How is tooth decay treated?

Treatments for tooth decay include liquids, gels (varnishes) and sealants. These treatments are painted onto the tooth to protect against bacteria. Treatment may also include fillings in larger cavities. Silver diamine fluoride (SDF) is a low‐cost liquid that can be painted on a tooth by a dentist or another trained person. It is suitable for people of all ages, including people with special health needs. However, SDF can permanently stain the treated tooth surface black or dark brown.

What did we want to find out?

We wanted to find out:

‐ if SDF was better than no treatment or other treatments at preventing new tooth decay, stopping existing tooth decay or preventing tooth decay from progressing;

‐ if there were benefits to applying SDF for different numbers of times, strengths of solution, or durations;

‐ if SDF caused unwanted effects, toothache, or if people were bothered by staining.

What did we do?

We searched for studies that compared SDF with no treatment or placebo (a dummy treatment), other treatments, or different application approaches. We compared and summarised the results of the studies and rated our confidence in the evidence, based on factors such as study methods and sizes.

What did we find?

We found 29 studies, with 12,020 children and 1016 older adults.

Main results

Compared with no treatment or placebo, we can't tell if SDF prevents new tooth decay in baby teeth or crown surfaces of permanent teeth. SDF is likely to prevent new tooth decay on root surfaces of permanent teeth. It may also completely stop existing tooth decay in baby teeth. However, we are unsure if it completely stops existing tooth decay on crown and root surfaces of permanent teeth, prevents existing tooth decay from progressing in any types of teeth, increases the risk of unwanted effects, or if people are bothered by the appearance of staining.

Studies used different combinations of treatment approaches (number of times SDF is applied and how often, the strength of solution, and duration of treatment). We can't tell if one approach is better than another at stopping or preventing further decay, unwanted effects, or bother with appearance of staining.

When SDF is compared with fluoride varnish, neither treatment may be better than the other at preventing new tooth decay in baby teeth. We are unsure about the effect on crown and root surfaces of permanent teeth. We also can't tell if either treatment is better than the other at stopping existing tooth decay or preventing further decay in baby teeth, or if there are any differences in unwanted effects, toothache, or bother with appearance of staining.

When SDF is compared with sealants, we can't tell if there are any differences between treatments in preventing new tooth decay on the crown surfaces of permanent teeth, or whether there are any differences between these treatments in unwanted effects.

When SDF is compared with fillings (with tooth decay first removed using only hand tools), we can't tell if there were any differences between treatments in stopping existing decay in baby teeth, unwanted effects, toothache, or bother with appearance of staining.

What are the limitations of the evidence?

Often we were very unsure of the evidence for the following reasons.

‐ SDF stains the teeth. Everyone in the studies would have known what treatment they were given. This might affect their usual teeth‐brushing routine. In most studies, the person checking teeth for new or existing decay would also have known this information.

‐ When we compared different approaches to SDF, the studies were too different from one another to allow us to compare them.

‐ Although we found 29 studies, most evidence was from individual (or few) studies, which were very small.

How current is this evidence?

The evidence is current to June 2023.

*This is a plain language summary of a review that is published in the Cochrane Library. You can find the full report of the review here: https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD012718.pub2/full#CD012718-abs-0002