Fluoride Dr Sara Mariyum 26/11/2018

FLUORIDE At. No. 9 At Wt. 18.4

Fluoride Trace element Accepted as required nutrient due to it protective role against dental carries and bone health. F is widely distributed in the lithosphere mainly as fluorspar, fluorapatite and cryolite, and is recognized as the 13th most common element in the earth’s crust.

Fluoride has both beneficial and detrimental effects on human health. In terms of dental health, the prevalence of dental caries is related to the concentration of fluoride in drinking water.

Fluorine: some initial comments In pure form, fluorine, is a very reactive gas (found in exceedingly small amounts in nature) But fluoride also exists widely in minerals bound to metals (e.g, sodium fluoride).

USES OF FLOURIDE COMPOUNDS In low concentrations, fluorides are used in human health applications. Fluorides such as sodium fluoride (NaF), sodium fluorophosphate (SMFP), and tin fluoride (SnF2),are common ingredients in toothpaste. Some dentists also give their patients semiannual fluoride treatments.

USES OF FLOURIDE COMPOUNDS In high concentrations, sodium fluoride may be found in rat poisons, insecticides, and wood preservatives. Hydrofluoric acid (HF), a very strong acid, is used in the etching of glass and other industrial applications, including integrated circuit manufacturing. Fluorine joins with carbon to form a class of compounds known as fluorocarbons.

Some of these compounds, such as dichlorodifluoromethane (CF2Cl2), were widely used in air conditioning and refrigeration systems and in aerosol spray cans, but have been phased out due to the damage they were causing to the earth's ozone layer.

PRESENCE OF FLUORIDE IN WATER F louride in sea water ----- conc. 1.2 – 1.4 mg/l Surface waters -------------- conc. < 0.1 mg/l Almost all food stuffs contain traces of Flouride . Water and beverages are the main sources of ingested F.

Safe and adequate intake of fluoride Adult is: = 1.5 – 4.0 mg/day For children 4 years and + = 1. 0 – 2.5 mg/day For toddlers 1 – 3 years = 0.5 – 1.5 mg/day For infants = 0.1 – 1.0 mg/day

SOURCES .Natural water .Food .In some areas, water in hot springs is enriched in dissolved fluoride. .Groundwater that has interacted extensively with fluoride-bearing bedrock can be enriched in dissolved fluoride.

sources Small amounts: fruits , vegetables and cereals Large amounts : water, sea foods and tea leaves

ABSORPTION Absorption of ingested fluoride is via the stomach and small intestine . Absorption of a standard dose of fluoride will vary from 100% on a fasting stomach, to 60% when taken with a calcium-rich breakfast.

FLUORIDE EXCRETION Renal excretion is the predominant route for removal of inorganic fluoride from the body. Approximately 50 percent of the daily intake of fluoride is cleared by the kidneys

Effect of fluoride on bone and teeth Sustained intake is required through out adult life for caries prevention Most important during early pregnancy and childhood (period of tooth development) It is also necessary for normal bone calcification Adequate intake at adulthood may decrease the incidence of osteoporosis

fluoride affects the metabolic activity of cells involved in bone deposition and resorption

caries Definition Dental cavities in the outer two layers of tooth. Causes Poor Oral Hygiene Practices Improper Nutrition

How does fluoride treatment prevent tooth decay ? Human teeth (and bones) are primarily composed of the mineral calcium hydroxyapatite Calcium hydroxyapatite has the chemical formula: Ca5[(PO4)3OH] One of the main components of this mineral is the hydroxyl ion Fluoride substitutes for the hydroxyl ion, producing calcium fluoroapatite, with the chemical formula: Ca5[(PO4)3F]

How does fluoride treatment prevent tooth decay ? Calcium fluoroapatite is chemically stable than calcium hydroxyapatite in acid environment of the mouth Calcium fluoroapatite dissolves at pH of 4.5 Calcium hydroxyapatite dissolves at pH of 5.5. This means that a higher concentration of calcium fluoroapatite in tooth enamel decreases tooth dissolution, and therefore can decrease the incidence of tooth decay.

Application types of fluorides Topically (on the surface) Systematically ( throughout the body)

Topical fluoride sources Toothpaste Mouthwash Professionally applied gels, foams, rinses Our own saliva

Fluoridated Toothpaste Important component of toothpaste Protects the tooth by making enamel harder Level of fluoride must be controlled and measured accurately Introduced around the world in the mid of 1950s

Protection by saliva Resting saliva is acidic in nature that causes demineralization At other times when your saliva is less acidic it just does the opposite, replenishing the calcium and phosphorus that keeps your teeth hard this is called reminerlization The loss of enamel is balanced by remineralization. In this process, minerals in the saliva, such as fluoride, calcium and phosphate, are deposited back into the enamel. Too much loss of minerals without enough replacement leads to tooth decay

Topical applications Helps to prevent cavities by strengthening the enamel Reducing the ability of bacteria contained in dental plaque to produce acid Re mineralizing existing dental cavities

Systematically fluoride sources Water Food Drops tablets

FLUORIDATION 20-40% reduction in caries over life time Over 250 million drink fluoridated water world wide 15% of UK water supplies are fluoridated Life Long-greatest Cario-protective Effect

ADVANTAGES Safe Cost-effective Consistent Good population coverage Compliance not needed Low risk of overdose

DISADVANTAGES Freedom of choice removed Complex infrastructure needed

Range of Addition Many of the western countries artificially fluoridate water and supply it to its people. The optimal conc. of fluoride varies according to climatic conditions in the range 0.5 mg-1.0mg/l, being generally recommended .

Upper Tolerable limit However there is clear evidence from India and China that skeletal fluorosis and an increased risk of bone fractures occur as a result of long-term excessive exposure to fluoride (total intakes of 14 mg fluoride per day), and evidence suggestive of an increased risk of bone effects at total intakes above about 6 mg fluoride per day.

Coverage Worldwide around 355 million people are receiving artificially fluoridated water. In addition around 50 million people receive water naturally fluoridated at a concentration of around 1 mg/l.

Is fluoridation of water the best solution to reducing tooth decay? Fluoridation of water must be undertaken with caution (taking into account natural concentrations of fluoride in the water supply) Also, the incidence of cavities is not wholly related to the need for fluoride For example, saliva can be more acidic in some individuals than others (leading to predisposition to tooth decay). Acidity of saliva is largely controlled by acid-producing bacteria feeding on sugars. So fluoridation is not always the best solution toward reducing tooth decay

FLUORIDE TABLETS AND DROPS 40-50% reduction in both adults and children NaF is compound of choice Care required in prescribing to minimize overdosage and fluorosis 0.5mg F/day in children 3 years and more

ADVANTAGES Effective Freedom of choice DISADVANTAGES: Compliance needed Consistency of delivery needed Risk of overdose

FLUORIDE SALT Effective Caries protective effect as good as fluoridation Dose pf 250ppm in adults and less in children ADVANTAGES: Freedom of choice Consistent and regular

DISADVANTAGES: Conflict with general health messages of reduction in salt intake and prevention of coronary heart diseases

FLUORIDE MILK Well absorbed although calcium diminishes topical effect ADVANTAGES: Safe Effective Regular Freedom of choice Small risk of overdose

DISADVANTAGES: Untested in community settings FLUORIDE IN FRUIT JUICES: few studies exist to support use

Fluorosis A chronic condition caused by excessive intake of fluorine compounds, marked by mottling of the teeth and if severe , calcification of bones

Dental fluorosis Excessive intake of fluoride damages enamel forming cells called ameloblasts, leading to abnormal development of teeth. Dental fluorosis is of particular concern during childhood when teeth are actively formed. Leads to increase in the porosity of enamel and a decrease in mineral content.

Degrees of dental fluorosis Very mild to mild (slight mottling of teeth) Moderate (obvious mottling of teeth) Severe (severe mottling of teeth)

Characteristics of dental fluorosis Caries Pulpits Brittle Sensitivity Esthetic

Treatment of fluorosis Tooth whitening Crowns Veneers Micro abrasion

Skeletal fluorosis Excess fluoride intake also interferes with normal bone development The early stage of skeletal fluorosis, is characterized by joint pain sensations of burning pricking, and tingling in the limbs muscle weakness chronic fatigue reduced appetite.

In the more advanced stages, pains in the bones become constant and some of the ligaments begin to calcify. Abnormal crystalline structure of the bones becomes apparent, and bony spurs begin to appear in joint areas. In the most advanced stage, the extremities become weak and moving the joints is difficult. The vertebrae partially fuse together, crippling the patient. Bones also become brittle.