Fluoride

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FLUORIDE

D.KARTHIKEYAN

PERIODONTOLOGY


INTRODUCTION

Minerals are the chemical elements required by living

organisms. This is also known as mineral nutrients.

Minerals are necessary for our body for three reasons.

They are

Building strong bones and teeth

Controlling body fluids inside and outside cells

Converting the food into energy.


Types of minerals

Minerals are broadly classified into two types

Macrominerals

Microminerals

Macrominerals

These are large and it is the diet mineral needed by

human body in high quantities. It is a group made up

of calcium, phosphorus, magnesium, sodium,

potassium, chlorine and sulfur


Microminerals

They are also called as trace elements .

micronutrients are chemical elements. Body

needs mineral each day in small amount for good

health. These are iron, manganese , copper,

iodine, zinc, fluoride, selenium etc.


FLUORIDE

Fluoride is the term for the ionized form of the

elemental fluorine as it occurs in drinking water. The

two terms fluorine and fluoride are used

interchangeably.


Historical background

In the early 1900s people noticed that inhabitants of

towns with naturally higher levels of fluoride in their

water had healthier teeth. To test the correlation

between fluoride and tooth decay , in 1945 four cities

in U.S and one in canada took part in the controlled

study of water fluoridation. The results were

impressive, establishing that fluoride prevents tooth

decay


SOURCES

Fluoride is present in small but widely varying

concentrations in particularly all soils, water

supplies, plants and animals. It is therefore a

constituents of all normal diets.

Fluorine is one of the atmospheric contaminants of

industries which use coal ore or earthly phosphates.


Fluoride is found in many foods, but sea food and tea

are the richest dietary sources.

An average daily diet provides 0.25 0.35 mg of

fluorine . In addition the average adult may ingest 1

1.5 mg daily from drinking and cooking water that

contains 1ppm of fluoride .

In children of age group of 1-12 years, water may

contribute anywhere from 0.4-1.1 mg of fluorine per

day.


RDA

The range suggested are obtained without

difficulty in the areas with the water supply

containing atleast 1mg/ litre of fluoride either

through naturally or fluoridation.


METABOLISM

Fluoride is a weak acid with pka of 3.4

Fluoride metabolism are pH dependent and that the

transmembrane migration of ion occurs due to

difference in acidity of adjacent body fluid

compartments.


Absorption

In absence of high concentrations of certain cations

such as calcium and aluminium , that form insoluble

compounds with fluoride about 80-90% of ingested

amount is absorbed from GIT.

Half time is 30 min, most of the fluoride that escapes

absorption will be absorbed from the proximal small

intestines.


EXCRETION

After about 50% of an ingested fluoride dose has

been absorbed, plasma concentrations decline rapidly.

This is due to renal excretion and uptake by calcified

tissues. Fluoride is freely filtered through the

glomerular capillaries and then undergoes a variable

degree of tubular re-absorption. Among the halogens,

the renal clearance of fluoride is unusually high.


FUNCTIONS

Fluoride supports mineralization of teeth and bones

by promoting deposition of calcium and phosphates.

Fluorides decreases the demineralization of tooth

enamel and accelerates subsequent remineralization

process.

Regular ingestion of fluoride is important during the

eruption of new teeth in children.


WATER FLUORIDATION

Water fluoridation is the controlled addition of

fluoride to a public water supply to reduce tooth

decay.

To bring the concentration of fluoride to 1ppm has

proved to be safe , economical and efficient way to

reduce tooth decay.

The concentration of fluoride in public water supplies

should be adjusted slightly to allow for difference in

water consumption with seasonal temperature

changes.


SALT FLUORIDATION

Sodium and potassium fluoride are used for

fluoridation of household salt.

In wet process, solution of potassium fluoride is

mixed homogenously with salt.

In dry process, sodium fluoride with a small grain

size is used.

The concentration of fluoride in salt used is in range

of 90-350ppm.


MILK FLUORIDATION

First mentioned by Zeigler in 1956 .

36.3% caries reduction was observed with 2.5mg of

sodium fluoride added to milk daily in school meals.

There was a controversy concerning the binding and

complexing of fluoride with calcium and milk protein

thus reducing its anti caries activity.

Erickson proved the availability of fluoride from

milk using radioisotope. But the release of fluoride

from milk is mild and slow compared to that of

water.


FLUORIDE TABLETS

Tablets are prescribed for individual patients

keeping in account the fluoride concentration in

drinking water and other fluoride supplement

consumed

Tablets should be swallowed or chewed and

available as 0.25mg. 0.5mg and 1mg.

Sodium, acidulated phosphate , potassium or

calcium fluoride is administered .


TOPICAL FLUORIDE

Topically applied fluoride are deposited onto the

surface of the tooth and they tend to provide local

protection at or near tooth surface.

Topical fluorides advocated for home use contain less

amount of fluoride and used daily.

Professionally applied fluoride agents contain very

high amount of fluoride and are applied less

frequently.


1. Solution / thixotropic gel

2. Dentrifice

3. Rinse

4. Varnish

5. Slow releasing systems


Acute fluoride toxicity

Safety tolerated dose is 8-16mg/kg body weight .

When fluoride is consumed beyond this limit it can

lead to toxicity. Lethal dose is 32-64 mg/kg body

weight.

SIGNS AND SYMPTOMS:

Nausea

Vomiting

Abdominal pain

Increased salivation


Nasal discharge

Generalized weakness

Carpodeal spasm

Reduced plasma calcium level

Increased plasma potassium level

Cardiac arrhythmia

Coma

Death


Management

5mg/kg

Milk

Induce vomiting

5 mg/kg

Milk

5% calcium gluconate

hospitalization

15mg/kg

Induce vomiting

Cardiac monitoring

Slow administration of 10ml of 10% ca. gluconate

Maintain adequate urine output


Chronic toxicity

Chronic toxicity is due to prolong ingestion of a

smaller amount of fluoride.

Chronic toxicity is associated with hard tissue and

kidney tubules

Skeletal fluorosis may occur at ingestion of 10-25mg

F/day for 20 years.


FLUOROSIS

Fluorosis is a chronic disease resulting from the

accumulation of toxic levels of mineral fluoride in

teeth and bones.

Characterized by bone overgrowth , brittle bones,

stiff joints, weakness, weight loss and anemia.

Mottling of enamel occur if exposure occur during

formation.


Causes are :

1. when the fluoride content of the drinking water

exceeds 2.5ppm.

2. When amount of fluorine ingested exceeds 30-40ppm

of the dry matter diet.

3. When a person consumes ( in food and water)

flourine in excess of 20mg/day over an extended

period of time.


Review article

Valeria CC Marinho, Julian PT Higgins in 2009

determined the effectiveness and safety of fluoride

varnishes, gels, mouth rinses, and toothpastes in the

prevention of dental caries in children and to examine

factors potentially modifying their effect. Children of

age 16 or less are included in the study.The benefits

of topical fluorides have been firmly established on a

sizeable body of evidence from randomized

controlled trials.


Philip E Benson, Nicola Parkin in 2009 evaluate the

effectiveness of fluoride in preventing white spots

during orthodontic treatment and to compare the

different modes of delivery of fluoride. 15 trials with

723 participants provided data for this review.There

is some evidence that the use of topical fluoride or

fluoride-containing bonding materials during

orthodontic treatment reduces the occurrence and

severity of white spot lesions.


References

http://onlinelibrary.wiley.com

INTAKE AND METABOLISM OF FLUORIDE Adv Dent

Res 8(1):5-14, June, 1994

Fluorides in the Environment: Effects on Plants and Animals

Leonard H. Weinstein, Alan Davison

Pediatric Dentistry: A Clinical Approach Goran Koch, Sven

Poulsen.

Advanced Nutrition and Human Metabolism Sareen Annora

Stepnick Gropper, Jack L. Smith, James L. Groff.

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Fluoride