Introduction

Fluoride is  most electronegative element which never exists in nature in free state. It combines with other elements to form a fluoride compound. Fluoride is present is lithosphere, hydrosphere, atmosphere and in all living organisms. Fluoride enters the atmosphere by volcanic eruption and interaction of soil and water vapour.

Importance of fluoride on teeth

• Fluoride is known to decrease the prevalence of dental decay.
• Exposure to fluoride before tooth eruption may produce teeth more resistant to decay by making the pits and fissures shallow.
• Enamel of teeth contains hydroxyapitite  crystals. Fluoride enters the enamel , reacts with the hydroxy apitite  of enamel to form fluorapitite and fluorhydroxy apatite.
• These new crystals contain fluoride which are less acid soluble. (increased acid solubility of enamel increases the chance of decay.)
• It reduces the ability of plaque bacteria to produce acid.
• Food that we eat gets stuck in between teeth and below gum line. Bacteria grows and acts on this food releasing acid. This acid attacks the  enamel of teeth. This causes dissolving of enamel and makes it weak.this process is called is demineralisation.
• When fluoride acts on it , this process gets reversed causing remineralization of enamel.

Modes of fluoride administration

1. Systemic fluoride
2. Topical fluoride

Systemic fluoride can be administered by

• Dietary fluoride. (e.g salt fluoridation, fluoride in sugar )
• Water fluoridation (school water fluoridation, milk fluoridation )

Topical fluoride can be administered by

• Professionally applied (applied by dentist in the form of gels , varnish, tooth paste)

• Self applied.

Fluoride concentration in drinking water in India

Fluoride in water is more in states like Gujarat , Rajasthan, Andhra Pradesh, Punjab , Haryana, Madhya Pradesh, Uttar Pradesh, Bihar, Maharashtra, Karnataka.

It is comparatively less in states like Uttaranchal, Jharkhand, chattisgarh, Assam, West Bengal, Kerala , Jammu Kashmir.

Hazards caused by fluoride excess

• According to WHO there is no substantial difference in tooth decay rate between countries that use fluoridated water and those who don’t.
• Fluoride which is added to water is fluorosilic acid which is a very harmful chemical.
• It posses a great threat not only to the dental health but also affects your bones, thyroid, brain, blood sugar levels. It can also cause cancer because of increased arsenic content.
• If fluoride is used in large amounts it causes fluoride poisoning and death. Lethal dose for adults is 5 – 10 gms.
• In low doses it causes nausea, vomiting, abdominal pain, diarrhoea, excess salivation, thirst.
• Chronic intake of fluoride during development of enamel can lead to a condition called fluorosis.

Fluorosis

Excessive intake of fluoride during enamel development/formation can lead to a condition called enamel fluorosis.

Cause of fluorosis

A developing enamel shows more affinity to fluoride. The hydroxyl apatite crystals of enamel bind to the fluoride ions. In fluorosis the enamel covering the teeth fails to mineralize properly which causes defects on the surface of enamel.

The risk of fluoride exposure is more in young individuals. Once all teeth have erupted in the mouth the incidence of fluorosis becomes nil.

Appearance of teeth having fluorosis

• In case of mild fluorosis there might be mild,tiny ,white streaks abut the surface of the tooth is smooth.

•  In case of moderate to severe fluorosis the enamel shows huge brown stains , pitting of enamel is seen giving the tooth a mottled appearance.
• The tooth shows porous areas which flake off or chip off . in these areas bacteria and debris get trapped . The tooth structure becomes weak causing structural damage, fracture and decay in teeth.
• When teeth having fluorosis gets decayed , it spreads rapidly into the nerve of the tooth causing pain.

Treatment

Treatment of fluorosis depends on the severity of fluorosis.

In mild cases

• Micro abrasion – i.e. removing little amount of enamel and then polishing the teeth with polishing discs.
•  
• Bleaching – 2 – 3 sittings of office bleaching (i.e. bleaching done in dental clinic ) with a gap of a week in between.

In moderate cases

• Composite fillings (tooth coloured fillings) can be done.
• Also dental veneers and caps can be done for moderate cases .

In severe cases

• In case of severe attrition of teeth, badly broken /chipped off teeth or situation where vertical height of jaw is lost , a meticulous treatment plan will be required.Treatment  plan will differ from patient to patient depending on the severity and extent of damage.

Precautions

• For children between 3- 4 years of age using fluoridated tooth paste, only pea sized amount of toothpaste should be taken on the brush.
• Brushing should be monitored by parents so that they do not intake the toothpaste.
• Fluoridated toothpaste should be used by the child only once. At other times non fluoridated toothpaste can be used.
• Topical fluoride application can be done from the age of 3 years.
• Do not use fluoridated mouthwashes until the age of 6.