Water Fluoridation

8.5.06

Methods of fluoride delivery
• Water fluoridation.
• Fluoride tablets and drops.
• Fluoride salt.
• Fluoride milk.
• Fluoride in fruit juice.
• Topical fluoride applications.
• Fluoride toothpaste.

How does fluoride work?
• Topical and systemic effect - topical effect more important.
• Fluoride incorporated into hydroxyapatite crystals in tooth - renders it more resistant to acid attack.
• Presence in saliva promotes remineralisation of tooth.
• Interferes with metabolic pathways of bacteria, thus reducing acid formation.

History
• McKay.
-"Colorado stain" identified (1901).
-Relationship between stain and caries noted (1929).
• Dean.
-Epidemiology of fluoride, enamel stain and caries (1931).
-Demonstrated inverse relationship between fluoride and caries with reduction at 1 ppm (part per million), and only mild stain at this level (1938).
• Trials in USA of artificially-fluoridated water.
• Trial in UK.
• Fluoridation schemes established in UK in 1960s.

Do we need water fluoridation?
• Prevalence of caries falling.
• Individual behavioural modification lowering caries.
• However, still a problem.

Issues associated with implementing water fluoridation
• Likely positive effects:
-Best available evidence suggest fluoridation of drinking water supply DOES reduce dental caries.
• Likely negative effects:
-Cancer.
-Down's syndrome.
-Bone fluorosis - fractures.
-Alzheimer's.
-Allegation that it may make men frisky.
-Fluorosis.
• Safety of fluoridation:
-Question of possible secondary effects caused by fluorides taken in optimal concentrations through life object of thorough medical investigation - shown to have no effect.
• Ethical issues:
-Autonomy - reduction of individual freedom has to be accepted for greater good.
-Beneficence and nonmaleficence - issues must be considered in terms of whole population.
-Justice - reduces inequalities in health.
• Legal issues:
-Enabling/mandatory frameworks.
-UK - enabling legislation - water companies can choose whether to fluoridate water or not.
-Mandatory - water companies obliged to fluoridate water.
-Water (Fluoridation) Act (1985).
-Water Act (2003).
• Environmental issues.
-No evidence of any adverse environmental effects.
-Chemicals used manufactured as co-product of manufacture of phosphate fertilisers.

Advantages
• Reaches everyone who might benefit from it.
• Cheap.
• 20-40% reduction in caries over a lifetime.
• Safe, cost-effective, consistent, good population coverage, compliance not needed, low risk of overdose.

Disadvantages
• Mass medication.
• Freedom of choice.
• Requires complex infrastructure at beginning and initial capital outlay.

Current situation
• 400 million people worldwide drink fluoridated water.
• 65% of USA population.
• 10% of UK population.

Conclusion
• Decreased caries.
• Cheap and effective.
• Reaches high-risk populations.
• Dental fluorosis at 1ppm very mild.
• Only effective in areas of high caries prevalence.
• Freedom of choice.