Silver diamine fluoride for caries management?

Caries is the world’s commonest disease. A number of topical fluoride agents have been used to prevent and arrest caries in primary and permanent teeth. Silver diamine fluoride (SDF) was cleared by the America Food and Drugs Agency in 2004 and there has been increasing interest in its use and a number of trials and reviews have suggested significant anti-caries activity.

The aim of this umbrella review was to provide a low-bias, comprehensive assessment on what the evidence from systematic reviews tells us about using SDF for management of carious lesions in children and adults.

Methods

Searches were conducted in the PubMed, Embase, Cochrane Data- base of Systematic Reviews and Joanna Briggs Institute Database of Systematic Reviews and Implementation Reports. The PROSPERO database was searches for registered systematic reviews in progress. Systematic reviews investigating SDF compared with active comparators, placebo and no treatment, for arresting or preventing coronal or root carious lesions in children and adults with or without carious lesions in primary and/or permanent teeth were considered.

Two reviewers independently screened and selected papers and extracted data in duplicate. A narrative summary of the breadth of evidence and adverse effects was undertaken, and meta-analyses would have been undertaken if possible. Overlap across the reviews was assessed using citation matrices and by calculation of the Corrected Covered Areas (CCAs). Risk of bias was assessed independently by two reviewers using the Risk of Bias in Systematic reviews (ROBIS)

Results

11 systematic reviews reporting on 63, of these 30 were unique.
11 reviews (26 studies) were related to coronal caries and 4 reviews (4 studies) to root caries.
5 reviews were limited to English language studies with only 3 reviews not imposing restrictions.
6 reviews considered only children while 4 reviews focused on root caries.
6 difference outcome measures were used.
8 reviews assessed bias using the Cochrane risk of bias tool or simplified versions.
2 reviews used the GRADE approach to assess quality.
5 reviews were at low risk of bias, 5 at high risk and one at unclear risk.
Root caries prevention
- All 4 reviews found that 38% SDF prevented and arrested more caries compared to placebo.
- Success rates were 72% higher for 38% SDF [1 high risk review- 1 study].
- MD (DMFRS/DFRS) was − 0.33 (95% CI = − 0.39, − 0.28) [1 high risk review- 2 studies].
- Preventive fraction (PF) was 25–71% [ 2 reviews,1 high risk, 1 low risk].
Root caries arrest
- PF = 100 to 72.5% higher for 38% SDF than placebo based on one high risk of bias review with data from two studies.
- One low risk review reported that 38% SDF was significantly more effective than placebo in arresting root carious lesions (no pooled results).
- One systematic review found that SDF can be efficacious to decrease progression of root carious lesions (no numeric results reported).
Coronal caries
- The reviews focused mainly on primary dentition all seven reporting that SDF outperformed the comparators.
- 3 reviews (1 high risk, 1 unclear risk and 1 low risk) reported on prevention. The PF for 38% SDF compared to placebo ranged from 70 – 78% in the primary dentition (2 reviews) and 64% in the permanent first molars (1 review with one study).
- Lesions arrest was reported in 6 reviews 3 at low risk, 2 at unclear and 1 at high risk of bias)
- Reported 38% SDF arrest rates in the primary dentition ranged from 65 to 91% (3 reviews)
- The PF ranged from 55 to 96% in favour of 38% SDF when compared to fluoride varnish or placebo in primary dentition (1 review, 2 studies).
- In the primary dentition the risk ratios (RRs) were 1.66 for SDF compared to fluoride varnish or Atraumatic Restorative Treatment and 2.54 compared with placebo/no treatment (1 review, 2 studies).
8 reviews reported on adverse effects mainly the black staining of the caries. No serious allergic reactions or toxicity was reported.

Conclusions

The authors concluded: –

Although there are not a large number of clinical trials, there is a consistent and progressively strengthening body of research that supports SDF’s effectiveness for arresting coronal carious lesions in children in the primary dentition and arresting and preventing root carious lesions in older adults. However, the evidence base around SDF for preventing coronal carious lesions in children was questionable based on the number and quality of studies. Moreover, there are too few studies and insufficient evidence to draw conclusions on the use of SDF in permanent teeth in children.

Comments

This umbrella review has been well conducted following established methodologies and the review provides a very useful summary of the current state of the evidence relating to SDF. However, it also raised a number of important issues. One is that a large number of reviews that have been conducted, 11 compared with the number of primary studies (30) this high ratio of reviews to primary studies can also be seen in other areas of dental research and is a potential waste of resources. In particular as the authors highlighted that the PROSPERO database had listed a further 6 that were in various stages of development with 3 apparently completed but as yet unpublished.

Of the SDF research identified for this umbrella review 13 of the 30 primary studies have been published in languages other than English and 5 of the SDF reviews specifically excluded, this could bias the review’s findings and impact upon the broader understanding of the effectiveness and adverse effects of the intervention. The broad range of outcome indicators used in the various studies emphasis the need to agree and use core outcomes sets to make future between study comparisons easier. There is also a continuing need to improve the quality of primary studies to ensure that the are well conducted and reported.

The Dental Elf