1. Water and food fluoridation

2. Lecture outline Introduction
Strengths and weaknesses of delivering fluoride in water or foods
Water fluoridation
Fluoride in natural water
Artificial water fluoridation
Evidence for water fluoridation
Milk and salt fluoridation

3. Introduction

4. Methods for fluoride delivery
Fluoride supplements:
Drops
Tablets
Fluoridated water
Fluoridated foods (salt, milk)
Home applied fluoride:
Toothpaste
Mouthwash
Fluoride in dental materials
Professionally applied fluoride
Gels
Varnish
Slow release devices

5. Ideal fluoride delivery
Long-term fluoride in the solution surrounding the enamel (topical effect).
Only a minimal amount of fluoride being systemically ingested.
Cost-effective.

6. Strengths and weaknesses of delivering fluoride in water or foods

7. Strengths of delivering fluoride in water or foods
A population-level action that ensures universal fluoride delivery.
Does not require conscious action by individuals.
Relatively cheap and can save manpower.

8. Weaknesses of delivering fluoride in water or foods
Consumption between individuals in a population might vary (thirst, use of bottled water).
Does not eliminate systemic ingestion.
Requires continuous quality monitoring.
Water fluoridation requires centralized water supply .

9. Water fluoridation

10. Fluoride in natural water sources
Fluoride is found naturally in seawater in concentrations of ppm.
In fresh surface water (Rivers, lakes), it is mostly in low concentrations (less than 0.5 ppm).
Highly variable concentration in groundwater (up to 300 ppm).
Groundwater is more vulnerable to fluoride enrichment due to the greater impact of water-rock reactions in aquifers (permeable rocks).

11. Fluoride in natural water sources
More than 200 million people around the world drink from sources that have a concentration higher the 1.5 ppm.
Groundwaters with high fluoride concentrations occur in many areas of the world.
Four “fluoride belts” have been identified
East African Rift valley from Eritrea to Malawi.
Turkey through Iraq, Iran, Afghanistan, India, northern Thailand and China.
Pacific coast of the Americas and
Japan.
Lake Nakuru in Kenya has the highest measured concentration (2800 ppm)

12. Fluoride belts

13. Jordan falls within a fluoride belt
Southern rtegions Tafila , Karak, Maan…high fluorosis rates

14. Is there a way to reduce fluoride concentration in water?
Difficult and expensive.
Produces toxic sludge.

15. Desalination Expensive Reduces fluoride in the water
Almost all fluoride is removed

16. Artificial water fluoridation
One of the 10 greatest public health
achievements of the 20th century.
1931: Dr H.T Dean noticed:
Increased fluoride concentration in water lead to higher prevalence of enamel mottling.
Reduced caries prevalence in children with access to fluoridated water in comparison to with non-fluoridated water.

19. What concentration of fluoride is most appropriate?
Dean noticed that the risk of enamel mottling increases significantly when the concentration of fluoride rises above 1 ppm.
His studies also showed that near maximal reduction in caries experience was at 1 ppm.
Based on work of Dean it was decided to fluoridate at 1 ppm in US
1 milligram per litre

20. Moller (1965) showed similar results in Sweden and Denmark

21. Rugg-Gunn et al. (1981) noted a similar pattern in the primary teeth of children in England

22. Impact of climate on recommended concentration
People in countries with warmer climate will consume more water.
Leads to increased ingestion of fluoride in comparison to colder countries.
An association between temperature and incidence of mottling has been noted.

23. WHO-recommended fluoride concentration
In 1984 the World Health Organization (WHO) issued a guideline on water fluoridation.
In warm climate: ppm
In cold climate: ppm
The permissible upper limit value: 1.5 ppm

24. Impact of water fluoridation
Studies demonstrated the efficiency of artificial water fluoridation using different methodologies:
Comparison with non-fluoridated areas
Comparison with naturally fluoridated areas
Comparison of caries experience in same area before and after fluoridation
Comparison of caries experience in the same area after cessation of fluoridation

25. The Grand Rapids-Muskegon study – first phase
The earliest study on artificial water fluoridation.
Carried out in the 1940s in the USA.
A Three armed trial:
1. Grand rapids – experimental town (added 1 ppm)
2. Muskegon – control (no F)
3. Aurora - naturally fluoridated (1.4 ppm)

26. The Grand Rapids-Muskegon study – first phase
Compared DMFT in children:
Caries experience in six-year-olds in the experimental town was half of that in control.
Caries experience in experimental town was similar to that in the naturally fluoridated town.

27. The Grand Rapids-Muskegon study – second phase
A longitudinal study.
Compared caries experience in children in Grand-rapids before and after fluoridation
Reported a reduction of caries experience by 50%
Fallen from 12 DMFT to 6.2 – fall of approximately 50%

28. Wick Study Carried out in the Scottish town of Wick
The town water was de-fluoridated in 1979.
Stephens et al. (1987) reported that the mean dmft of five-year-olds in the town went from 2.63 to following de-fluoridation (50% increase).

29. Impact of water fluoridation
Other studies in the USA (Newburgh-Kingston; Evanston-Oak Park), and in the UK (Kilmarnock-Ayr; Watford-Sutton) solidified the positive findings.
1 ppm F in water reduces caries experience by 40-49% in primary teeth, and 50-59% in permanent teeth.
Looking at ersults of 113 worlwide studies of water fluoridation

30. Possible issues with water fluoridation
A type of universal medication that can be considered an infringement of personal rights.

31. Possible issues with water fluoridation
UK – 10%
USA – 60%
Brazil – 42%
Ireland – 67%
Scandinavian countries – deactivating fluoridated areas

32. Possible issues with water fluoridation
Some groups are concerned with a possible link to increased risk of cancers and bone fractures.
Increased incidence of fluorosis.

33. York review of water fluoridation (2000)
Supported that water fluoridation :
Reduces caries risk.
Reduces discrepancies between social classes.

34. York review of water fluoridation (2000)
No evidence of increased risk of bone fractures (see figure)
No increased risk of bone or thyroid cancers

35. Cochrane review of water fluoridation (2015)
Water fluoridation reduces dmft by 35% and DMFT by 26% in children. Evidence in adults was not available.
At 0.7 ppm, 40% of the population showed signs of fluorosis,12% had aesthetic concerns.

36. Cochrane review of water fluoridation (2015)
The majority of studies available are old (prior to 1975).
This is an issue since fluoridated toothpaste was introduced in the 1970s.
Need new studies to evaluate if water fluoridation still has value.

37. Milk and salt fluoridation

38. Fluoridated foods
Fluoridated foods were suggested as a substitute for water fluoridation.
Salt and milk and, to a lesser extent, sugar, bread, and cereals were proposed.
The use of foods, when non-fluoridated alternatives are also available in the market gives individuals more choice than water-fluoridation.
Needs to be accompanied by promotion and education.

39. Fluoridated salt
Introduced in the 1960s in Hungary, Switzerland and Colombia.
Provided in a concentration of 250 ppm.
Caries preventive effect approximates that of fluoridated water.
Recommended by WHO as one alternative method to Fluoridated water

41. Fluoridated salt
Measurement of impact was complicated by other fluoride sources (toothpaste, tablets).
Impact in 0-3 year olds minimal due to low consumption.
Not recommended in countries where water is fluoridated.

42. Fluoridated milk
Bovine and human milk contain 0.03 ppm fluoride. Artificially fluoridated milk usually has the concentration of 2.5 ppm.
Introduced in Germany, Austria, Switzerland, and Japan

43. Fluoridated milk
Binding of added fluoride to calcium or milk proteins might reduce the topical effect.
A Cochrane review noted that there is low quality evidence that fluoridated milk can reduce caries in primary teeth, but further research is needed.

44. Thank you