Slow-release fluoride devices for caries prevention: insufficient evidence


Dental caries is a very common disease although it is not distributed evening amongst the population. Consequently, targeting those at greatest risk has potential benefits while there are some that caution that approach.  The use of topical fluorides is a key element in caries prevention and they may be delivered in a range of formats eg. tablet, rinses, toothpastes gels and varnishes. While agents these provide a  short term raising of fluoride levels the use of more sustained slow-release devices which provide a more sustained presence of fluoride have been tested.

The aim of this review was to evaluate the effectiveness and safety of different types of slow-release fluoride devices on preventing, arresting, or reversing the progression of carious lesions on all surface types of primary (deciduous) and permanent teeth.


Searches were conducted in the Cochrane Oral Health’s Trials Register; the Cochrane Central Register of Controlled Trials (CENTRAL); Medline; Embase; The US National Institutes of Health Ongoing Trials Register, and the World Health Organization International Clinical Trials Registry Platform with no language or date restrictions. Parallel design randomised controlled trials (RCTs) involving all types of slow-release fluoride devices were considered.  The primary outcome was change in decayed, missing or filled teeth (or surfaces) in primary of permanent teeth.  Standard Cochrane data abstraction and analysis approaches were used.


  • No evidence was found to compare slow release fluoride devices against other types of fluoride therapy
  • 1 RCT (174 children) at high risk of bias compared   a slow-release fluoride device (glass beads with fluoride were attached to buccal surfaces of right maxillary first permanent molar teeth) against control (glass beads without fluoride were attached to buccal surfaces of right maxillary first permanent molar teeth).
  • Analysis on 63 children  ( very low quality evidence) who retained the beads demonstrated a statistically significant reduction in:-
    • DMFT;  mean difference(MD)=  -0.72, (95%CI; -1.23 to -0.21).
    • DMFS; MD= -1.52, (95% CI -2.68 to -0.36)
  • Harms and other outcomes (caries progression, pain etc) were not reported.


The authors concluded: –

There is insufficient evidence to determine the caries-inhibiting effect of slow-release fluoride glass beads. The body of evidence available is of very low quality and there is a potential overestimation of benefit to the average child. The applicability of the findings to the wider population is unclear; the study had included children from a deprived area that had low levels of fluoride in drinking water, and were considered at high risk of caries. In addition, the evidence was only obtained from children who still had the bead attached at 2 years (48% of all available children); children who had lost their slow-release fluoride devices earlier might not have benefited as much from the devices.


This review updates the 2014 Cochrane review ( Dental Elf -2nd Dec 2014) and there is still only a single trial assessing the effectiveness of slow-release fluoride agents for the prevention of caries. While the included study did demonstrate a reduction in decay that was considered to be clinically important this was only the case in those children who retained the bead for 2 years.  In fact the beads were  only intact in less than half (47.7%) of participating children.  Given that other methods of topical fluoride delivery notable toothpastes and fluoride varnish are widely used and have good evidence supporting their effectiveness we should focus on these approaches which encourage regular positive behaviours (toothbrushing) and regular dental visiting (fluoride varnish applications) rather a ‘fit and forget’ approach (although not intended as such).


Primary Paper

Chong LY, Clarkson JE, Dobbyn-Ross L, Bhakta S. Slow-release fluoride devices for the control of dental decay. Cochrane Database of Systematic Reviews 2018, Issue 3. Art. No.: CD005101. DOI:10.1002/14651858.CD005101.pub4.

Other references

 Cochrane Oral Health Group Blog: Slowly does it: no evidence that slow-release fluoride devices are effective


 Dental Elf – 2nd Dec 2014

Slow-release fluoride devices: review finds insufficient evidence to show they reduce dental decay


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Derek Richards

Derek Richards is a specialist in dental public health, Director of the Centre for Evidence-Based Dentistry and Specialist Advisor to the Scottish Dental Clinical Effectiveness Programme (SDCEP) Development Team. A former editor of the Evidence-Based Dentistry Journal and chief blogger for the Dental Elf website until December 2023. Derek has been involved with a wide range of evidence-based initiatives both nationally and internationally since 1994. Derek retired from the NHS in 2019 remaining as a part-time senior lecturer at Dundee Dental School until the end of 2023.

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