Fluoride

Date: December 2016

 Fluoride has long been used as a means of protecting the teeth from caries. It
can be used in a variety of ways, such as fluoride toothpaste, fluoride rinses, Do topical fluorides (toothpaste, varnish, mouthrinses,
fluoride varnish, systemic fluorides (tablets, drops, lozenges and chewing gums), gel) prevent caries?
fluoridated milk and targeted water fluoridation. This Fact File examines the
evidence for the use of fluoride as a means of preventing dental caries and The effectiveness of some topically applied fluorides such as toothpaste, varnish
reducing oral health inequalities. and rinses in preventing dental caries has been well established in systematic
reviews of randomised controlled trials conducted in children.3-5
Introduction
Regular use of fluoride toothpaste is known to be effective in preventing caries
Tooth decay is a significant problem in parts of the UK and dental health in the permanent dentition.5 There is an apparent dose-response relationship
inequalities are increasing. In socially deprived communities, as many as one between the amount of fluoride and the level of caries prevention. A Cochrane
in three children under the age of five will have one or more decayed teeth systematic review found that the prevented fraction (based on the number of
extracted. decayed, missing or filled surfaces) was 23 per cent for fluoride at 1,000-1,200
ppm (parts per million) - i.e. the use of toothpaste at this fluoride concentration
Fluoride is a naturally occurring mineral that has a history of being used as prevented 23 per cent of the decayed, missing or filled surfaces that would have
a means of reducing dental decay (caries). It can be brought into contact been observed without use of the toothpaste.6 This increased to 29 per cent
with teeth in a number of ways, including fluoride toothpaste, fluoride rinses, for fluoride concentrations of 1450-1500 ppm, and to 36 per cent for higher
fluoridated milk and fluoride varnish. In some areas, fluoride is added to water as concentrations of fluoride (2,400-2,800 ppm). The prevented fraction for 440-
a means of reducing caries in the population. Although the post-eruptive effect 550 ppm fluoride was 15 per cent, but this is not statistically significant.6
of fluoride is now considered to be more important that the pre-eruptive effect,
fluoride supplements where the fluoride is administered systemically can also be The application of fluoride varnish has also been shown to be effective in both
used to reduce caries. the primary and permanent dentition. The prevented fraction (based on the
number of decayed, missing or filled surfaces) in permanent teeth was 43 per
What is fluoride and how does it work? cent.3 The prevented fractions for fluoride gels and mouthrinse were found to
be of a similar order to that of toothpaste at 1,000-1,200 ppm, with prevented
Fluoride is a mineral found naturally in water and in many foods. Bringing fractions of 27 per cent for mouthrinses4 and 28 per cent for gels.7 A meta-
teeth into contact with fluoride (topical effect) can make a big difference to analysis comparing the use of fluoride gel, mouthrinse or varnish combined with
the standard of oral health by reducing caries. Dental caries occurs through toothpaste, compared with toothpaste alone, indicated a 10 per cent prevented
demineralisation of dental hard tissue. Fluoride works to improve oral health fraction.8
by enhancing remineralisation and reducing the acid production ability of
plaque-forming bacteria, thereby protecting against caries.1 The acids causing Does milk fluoridation prevent caries?
demineralisation of dental hard tissue are formed from the action of plaque
bacteria on sugars in the diet; therefore it is recommended that the frequency There is low quality evidence to suggest fluoridated milk may be beneficial to
and amount of sugars in the diet should be reduced.2 A maximum protective schoolchildren, contributing to a reduction in dental caries in primary teeth.9
effect occurs when teeth erupt into an environment with high concentrations of
fluoride.

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 Do fluoride supplements (tablets, drops, lozenges or What about dental fluorosis?
chewing gum) prevent caries?
Dental fluorosis can be a possible adverse effect following ingestion of excessive
There is moderate quality evidence that fluoride supplements, in the form of topical fluoride by young children. In its mildest form, dental fluorosis presents
tablets, drops, and lozenges, reduce caries (prevented fraction 24 per cent) in the as faint white lines and in its most severe form as brown staining or pitting of
permanent dentition. The evidence for their effect on the primary dentition is the tooth enamel. A Cochrane review looked at the relationship between topical
unclear. There is no evidence for the effectiveness of fluoridated chewing gum.10 fluorides and dental fluorosis.16 Most of the available evidence focussed on mild
fluorosis and there was a lack of robust evidence examining the topic. Weak
What is the evidence that fluoridated water is beneficial? evidence was found that starting the use of fluoride toothpaste in children under
the age of 12 months may be associated with an increased risk of mild fluorosis.
In 2015, the Cochrane Oral Health Group published a review on water
fluoridation.11 It found that there was very little contemporary evidence, meeting The Cochrane review11 highlighted that fluoride can cause dental fluorosis and
the review’s inclusion criteria, that has evaluated the effectiveness of water found a dose-response relationship between water fluoride level and fluorosis
fluoridation for the prevention of caries. The available data came predominantly prevalence. The MRC report10 recommended further research to ascertain
from studies conducted prior to the widespread use of fluoride toothpaste, and prevalence and establish the public perception of fluorosis.
indicate that water fluoridation is effective at reducing caries levels in both
deciduous and permanent dentition in children. The review concluded that Does fluoride cause systemic health problems?
confidence in the size of the effect estimates is limited by the observational
nature of the study designs, the high risk of bias within the studies and, The major reviews of the evidence, including the York and MRC reviews, found
importantly, the applicability of the evidence to current lifestyles. The review did no reliable evidence to support claims that fluoridated water causes cancer,
not identify any evidence, meeting the review’s inclusion criteria, to determine bone disease, kidney disease or birth defects. Reports suggesting harmful effects
the effectiveness of water fluoridation for preventing caries in adults, and there often refer to studies in which the concentration of fluoride was much higher
was insufficient information to determine the effect on caries levels of stopping than the recommended level. The safety of fluoride is under constant review, and
water fluoridation programmes. the latest reports from both Public Health England17 and the SCHER15 indicate
that there is no reliable evidence that health problems other than fluorosis are
Earlier reviews (York, 2000)12; Medical Research Council (MRC),200213; caused by fluoride.
Australia,200714 and more recently the European Commission (SCHER), 2011)15
have generally shown water fluoridation to be beneficial in reducing caries, Is fluoride the only measure for preventing dental decay
although the size of the effect is unclear. The Cochrane review, York review and at population level?
MRC report highlight the need for more good quality research.
No. We suggest that every local area should have an oral health strategy that
Does the use of fluoride reduce health inequalities? considers all effective methods to improve local oral health.

Cochrane reviews have examined the interaction between the preventive effect As well as methods of increasing the availability of fluoride – be it through fluoride
(measured as prevented fraction) of each type of topical fluoride and baseline toothpaste, fluoride varnish, fluoride rinses, or fluoridated water – strategies to
levels of caries – i.e. whether each type of topical fluoride was more effective reduce dental decay should emphasise the strong recommendation by the UK
when the initial level of caries was higher.3-5,7 No specific interaction was Scientific Advisory Committee on Nutrition18 and WHO19 that both adults and
found for fluoride gels, mouthrinses, or varnish. However, the effect of fluoride children should reduce their intake of free sugars to less than 10 per cent of total
toothpaste was found to increase as the level of caries increased, indicating that energy intake throughout the lifecourse. Efforts should also be made to identify
fluoride toothpaste can be effective in reducing inequalities. The Cochrane and sugar-free medicines, improve periodontal health, provide smoking cessation
York reviews concluded that the available evidence did not allow a conclusion guidance, address alcohol misuse and prevent tooth erosion.
to be reached on whether water fluoridation reduced dental health inequalities.

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 Acknowledgement 9. Yeung CA, Chong LY, Glenny AM. Fluoridated milk for preventing dental
caries. Cochrane Database of Systematic Reviews 2015, Issue 9. Art. No.:
This Fact File was updated by Professor Helen Worthington, Professor of Evidence CD003876. DOI: 10.1002/14651858.CD003876.pub4.
Based Care, University of Manchester School of Dentistry and joint co-ordinating 10. Tubert-Jeannin S, Auclair C, Amsallem E, Tramini P, Gerbaud L, Ruffieux
editor, Cochrane Oral Health Group. C, Schulte AG, Koch MJ, Rège-Walther M, Ismail A. Fluoride supplements
(tablets, drops, lozenges or chewing gums) for preventing dental caries in
References children. Cochrane Database of Systematic Reviews 2009, Issue 1. Art. No.:
CD007592. DOI: 10.1002/14651858.CD007592.
1. Cheng KK, Chalmers I, Sheldon TA. Adding fluoride to water supplies. BMJ. 11. Iheozor-Ejiofor Z, Worthington HV, Walsh T, O’Malley L, Clarkson JE, Macey R,
2007 Oct 6;335(7622):699-702. Alam R, Tugwell P, Welch V, Glenny A-M. Water fluoridation for the prevention
2. Department of Health and British Association for the Study of Community of dental caries. Cochrane Database of Systematic Reviews 2015, Issue 6.
Dentistry. Delivering better oral health: an evidence based toolkit for Art. No.: CD010856. DOI: 10.1002/14651858.CD010856.pub2.
prevention; 2014. https://www.gov.uk/government/uploads/system/uploads/ 12. McDonagh MS, Whiting PF, Wilson PM, Sutton AJ, Chestnutt I, Cooper J, et al.
attachment_data/file/367563/DBOHv32014OCTMainDocument_3.pdf. Systematic review of water fluoridation. BMJ. 2000 Oct 7;321(7265):855-9.
Accessed 1 December 2016. 13. Medical Research Council. Medical Research Council working group report:
3. Marinho VCC, Worthington HV, Walsh T, Clarkson JE. Fluoride varnishes Water fluoridation and health, 2002. http://www.mrc.ac.uk/publications/
for preventing dental caries in children and adolescents. Cochrane browse/water-fluoridation-and-health/. Accessed 1 December 2016.
Database of Systematic Reviews 2013, Issue 7. Art. No.: CD002279. DOI: 14. The Australian Government National Health and Medical Research Council.
10.1002/14651858.CD002279.pub2. A systematic review of the efficacy and safety of fluoridation; 2007. http://
4. Marinho VCC, Chong LY, Worthington HV, Walsh T. Fluoride mouthrinses www.nhmrc.gov.au/guidelines/publications/eh41. Accessed 1 December
for preventing dental caries in children and adolescents. Cochrane 2016.
Database of Systematic Reviews 2016, Issue 7. Art. No.: CD002284. DOI: 15. European Commission Scientific Committee on Health and Environmental
10.1002/14651858.CD002284.pub2. Risks. Critical review of any new evidence on the hazard profile, health
5. Marinho VCC, Higgins J, Logan S, Sheiham A. Fluoride toothpastes effects, and human exposure to fluoride and the fluoridating agents of
for preventing dental caries in children and adolescents. Cochrane drinking water, 2011. http://ec.europa.eu/health/scientific_committees/
Database of Systematic Reviews 2003, Issue 1. Art. No.: CD002278. DOI: environmental_risks/docs/scher_o_139.pdf. Accessed 1 December 2016.
10.1002/14651858.CD002278. 16. Wong MC, Glenny AM, Tsang BW, Lo EC, Worthington HV, Marinho VC.
6. Walsh T, Worthington HV, Glenny AM, Appelbe P, Marinho VC, Shi X. Fluoride Topical fluoride as a cause of dental fluorosis in children. Cochrane Database
toothpastes of different concentrations for preventing dental caries in Syst Rev. (1):CD007693.
children and adolescents. Cochrane Database Syst Rev. (1):CD007868. 17. Public Health England. Water fluoridation Health monitoring report for England
7. Marinho VCC, Worthington HV, Walsh T, Chong LY. Fluoride gels for preventing 2014.https://www.gov.uk/government/publications/water-fluoridation-
dental caries in children and adolescents. Cochrane Database of Systematic health-monitoring-report-for-england-2014. Accessed 25 January 2017.
Reviews 2015, Issue 6. Art. No.: CD002280. DOI: 10.1002/14651858. 18. Scientific Advisory Committee on Nutrition. Carbohydrates and health report,
CD002280.pub2. 2015. https://www.gov.uk/government/publications/sacn-carbohydrates-and-
8. Marinho VC, Higgins JP, Sheiham A, Logan S. Combinations of topical fluoride health-report. Accessed 25 January 2017.
(toothpastes, mouthrinses, gels, varnishes) versus single topical fluoride for 19. Guideline: Sugars intake for adults and children. Geneva: World Health
preventing dental caries in children and adolescents. Cochrane Database Organization, 2015.
Syst Rev. 2004(1):CD002781.

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