Fluorides third year class

DR. PAWAN SINSINWAR
DEPARTMENT OF PEDIATRIC AND PREVENTIVE
DENTISTRY

CONTENT
 Introduction
 Historical evolution of fluorides
 Fluoride chemistry and occurrence
 Total intake of fluoride
 From Air
 From Water
 From Food
 Fluoride metabolism and bioavailability
 Physiologic distribution of fluoride
 In blood and soft tissue
 In hard tissue

 Excretion of fluoride
 Placental transfer of fluoride
 Water fluoridation
 School water fluoridation
 Fluoride tablets
 Fluoridated salt
 Fluoridated milk
 Fluoridated flour and sugar
 Toxicity of fluoride
 Defluoridation

HISTORY
 In 1805, Morichini found fluoride in human Enamel.
 Fluorine discovered by chemist Scheele in 1771- isolated by Moissan in
1886
 First report of fluoride concentration in drinking water quoted in ppm
given by Hillebrand.
 Desirabode in 1847 referred to fluates-(silicate or fluate of lime and
alumine, dried and pulverized)
 First reference to prophylactic role of fluoride made by Erhadt in 1874
 Fluoride pills (KF) recommended in England, comes in pleasant tasting
form as “hunter pills”
 Dr A. Denninger (1896)- Fluoride an agent to combat dental disease
and Appendicitis

 In 1901 Dr. Federick Mckay- “Colorodo Stains”
minute white flecks, yellow or brown spots scattered..
 In 1902 Dr. J.M. Eager noticed in Italian emigrants -“denti di chiaie”
 1916, Dr. Green supported Mckay work with histologic evidence “ an endemic
imperfection of the enamel of the tooth
 In 1918 Dr. O. E. Martin and Mckay- Britton (1898) changed water supply from
shallow wells to deep drilled artesian wells….
 1931 Mr. H. V. Churchill- spectrographic analysis of Bauxite
city water 13.7ppm

 in 1933, Dr. H. Trendley Dean- conducted “Shoe Leather Survey”
in 97 localities, with a aim to find out minimal threshold level….
 In 1939 came out with ‘domestic water is primary cause of human
mottled enamel ( dental fluorosis)’
 In the same year- hypothesis showing ‘inverse relationship
between endemic fluorosis and dental caries’

Fluoride chemistry
& occurrence -
 Greek “floris”- destruction
 Latin “fluor”- flow or flux
 Symbol- “F”
 Atomic no.- 9
 Atomic weight- 18.99
 It is a pale yellow, corrosive
gas, which reacts with
practically all organic and
inorganic substances
 Most electronegative of all
elements

 Reasons for high reactivity:- 1s2, 2s2, 2p5
 Most electronegative of all elements
 Small size of atom
 High electron affinity
 Small bond length

 17th in order of abundance of all elements
 Constitutes about 0.032% in earth’s crust
 Fluoride containing minerals-
 Fluorspar (CaF2) - 48.8%
 Cryolite (Na3AlF6) – rare
 Fluorapetite Ca10(PO4)6F2- 3.8%

Fluoride In Air
 HF or Gaseous F2
 Dust of f2 containing soils, gaseous industrial, coal
smoke,
and volcanic emulsion.
 Levels of air borne- Aluminum factories: 5micro grams/
m3

Fluoride in plants
 Roots form soil and Leaves form air
 Camellia sinensis –acidic soils,
 Indian Tea leaves – 70 to 375 ppm
 Vegetables- factories- 10ppm
 Fruits and vegetables- 0.2 to 0.5 microgram/gram wet
wt.
grown near aluminums

Fluoride In Animal Products
 Beef, pork and mutton-0.3ppm
 Higher in Chicken- contamination bone and cartilage
fragments
 Fish products- up to 20ppm
 Dried sea foods also fluoride rich 84.5ppm (South East
Asia)

Fluoride In Beverages
 Ranges from 0.05 to 1.05 ppm
 Fluoride content in alcoholic beverages generally
reflects that of water used.

Total daily intake of fluoride
Fluoride from Air
 Minimal
Fluoride from Water
 Most important single source of fluoride
 Dependent on fluoride concentration and amount
 Fluctuation –climatic and geographical areas
Fluoride from food
 0.3 to 0.6 mg/day
 Fluoride intake 6months of life-bottle/breast fed
 Breast fed infant receives 0.003 to 0.004mg/day- formula fed
infants (1.2ppm) fluoride intake increased 50 times

 Excessive consumption of tea and sea foods- increased flr
 National Research Council 1980 – safe and adequate
1.5 to 4.0 mg/day in adults
0.05 to 0.07 mg/day in children for optimal dental
health
Threshold level drinking water 2.0ppm- dental fluorosis

Fluoride metabolism & Bioavailability
 Therapeutic action and safety of fluoride – kinetic process
Mechanism and site of absorption:-
 Water soluble fluorides- NaF, HF, H2SiF6, Na2PO3F and
StF
 Less soluble fluorides- CaF2 , Ca10(PO4)6F2
 Passive in nature
 Rapid absorption stomach- nonionic diffusion of HF
 Ph of gastric fluid-free F in the form of HF
 With milk, F bioavailability decreased..
 Formation of low soluble calcium fluoride
 Binding to casein and colloidal calcium phosphate
 Clotting of milk (acidity)-physical barrier over mucosal

 Absorption from solid foods is less compare to liquid
 80% of ingested is absorbed
From fluoride preparation and dental materials:-
 Dentifrices- less
 Alginate (4450 to 24,240 ppm)- systemic absorption peak in
30 min
Single impression Zelgan- 119ng/ml in plasma level
Double impression -200ng/ml
150 ng/ml from 3mg F in aqueous solution
 Fluoridated anesthesia- halothane, Methoxyfluorane,
Enflurane -630ng/ml

PHYSIOLOGIC DISTRIBUTION OF
FLUORIDE
Fluoride in Blood:-
 Blood plasma is most reliable indicator
 ¾ in plasma and ¼ in RBC
 Fluoride exists in both forms
-bounded from
-ionic form- varies concentration F in drinking water
 Increase in plasma F with age and in presence of renal failure
Drinking water 0.25 or 1.25 ppm –plasma level 0.01 or 0.025ppm
Increased reactive sites and voids in old bone is more saturated and
filled with F than young bone

Fluoride In Soft Tissue
 Tissue/ plasma ratio = 0.4 to 1
 Ectopic calcification loci- F accumulation in Aorta,
tendon, cartilage and placenta

Effects On Kidney
 Fluoride is normally cleared from the blood by
deposition in bone, excretion in urine- unable to find
toxic effect on kidney endemic fluorosis.
 Patients with chronic renal failure- dialysed with
fluoridated have additional load of fluoride
So fluoride free water is used for kidney dialysis

Bone:-
 Total amount-2.6mg
 Most of F in the body retained in the skeleton-vary according
to the renal clearance
 F enter in mineralized tissue-replacing 0H-, C03
2- and HC03
-
 Remodeling bones deposit more fluoride than older people
 Fluoride deposition is a reversible process

Teeth:-
 Deposition occurs in successive stages.
Initial deposition – organic and mineral phases are laid down
Pre-eruptive maturation phase-before eruption
Post eruptive maturation and aging period
 Dentine contains 4 times more than enamel
 Fluoride concentration not uniform
 Fluoride concentration –initial stages is higher than on completion
( mineralization process- release of F to the bathing fluid)
 Primary teeth less fluoride concentration than permanent teeth

 Permanent teeth
 Primary teeth
 Non-fluoridated areas
 Fluoridated areas
 1100ppm
 2200ppm
 670ppm
 950ppm

 F concentration in newly erupted teeth- higher in in
incisal than cervical margin
 Diffusion of F in enamel NaF and
monoflurophosphate(100pmm)-
10-9cm2/sec
 Speed at which F penetrates in enamel-
38 micrometer/ hour (186micrometer/ day)

Concentration in dentin:-
more than enamel-apatite crystals are smaller
-surface area and capacity to take is much larger
In permanent teeth:
Highest near the pulpal surface
low in secondary dentin
In primary teeth
complicated –physiologic resorption occurs towards pulpal side
greatest rise and fall – Pulpal surface of multirooted teeth

Fluoride concentration in
Cementum:-
 Higher than any skeleton or dental tissue
 Tissue is very thin
 Near the tissue surface- accessible to fluoride present in
blood
 Increases with age

Mechanism Of Action Of Fluoride
In Caries Reduction.
 Increased enamel resistance (or) reduction in enamel
solubility
 Increased rate of post eruptive maturation
 Remineralization of incipient lesions
 Interference with plaque microorganisms
 Modification in tooth morphology

Enamel Fluorosis
 Enamel mottling described by Eager in 1901 in Naples & Italy
 Black and Mckay In 1916 in Colorodo and Arizona
 Relationship between enamel mottling & excessive intake of fluoride in
1931 by Smith etal, Churchill JV, and Velu R etal
 H. Trendley Dean and Arnold –Mottling : Concentration of fluoride in
drinking water
 Moderate to severely pitting and staining: pre-eruptively induced
enamel porosity

 2 to 10 ppm- direct inhibitory effect on enzymatic function
of Ameloblasts: resulting in defective matrix formation and
subsequent hypominerlization
 Hypocalcified enamel easily becomes hypoplastic after
eruption due to abrasion and wear
 No fluorosis- additional intake of F once crown formed and
topical applications

CRITERIA FOR DIAGNOSIS OF ENAMEL FLUOROSIS
Dean
score
Criteria
0
0.5
1.0
2.0
3.0
4.0
-Normal enamel
-Questionable mottling: normal
translucency is varied by a few
white flecks or white spots.
-very mild mottling: white opaque
areas are scattered over the teeth;
<25%
-Mild mottling: not more than 50%
-Moderate mottling: all enamel
surfaces are effected
Show marked wear; brownish
stains are frequent

OSTEOFLUOROSIS
 Common in workers of aluminum factory
 Endemic fluorosis :India, China, South Africa
 Fluoride dosage: 10 to 25 mg/day for a period of 10 to 20 years
 Threshold level for osteofluorosis appears: 4000 to 6000 mg/kg
of dry fat free bone
 First stage: asymptomatic (radio graphically – increase density of
vertebrae pelvis)
 Advanced cases: bone density increased
bone contours and trabeculae uneven and blurred
extremities show thickening of compact bone
irregular periosteal growth ( exostoses and osteophytes)
increased in calcification in ligaments, tendons, and
muscle insertion

At this stage complaints: vague pain in small joints. knee
joints and joints of spine
 Increased severity “crippling fluorosis”:
stiffness of spine
limitation of movements
severe pain

SOFT TISSUE FLUOROSIS ARE WE
NEGLECTING????
 A team of Japanese professors found that children with mottled
teeth have high incidence of heart damage than those without
mottling (Tokushima J 1961)
 Chronic exposure to F showed stomatitis and oral ulcer (Sheajjet
etal 1967)
 Optical neuritis and visual disturbance may result from direct
effect of fluoride ion on neural tissue (Ellenhorn MJ 1988)

 Increased cases of reduced IQ, and mentally retarded pt. in endemic
fluoride region (Xang et al 2003)
 Pineal gland contains more fluoride than any other soft tissue in the
body (Jennifer Luke,1997)
 Chronic atrophic gastritis (Dasavathy et al 1996)
 Decreased testosterone concentration (Susheela et al)
 Damaged sperms, reduced sperm count and reduced fertility (Gosh et
al 2002)

EXCRETION OF FLUORIDE
3 main avenues are urine, feces and perspiration
Via kidneys:-
 40 t0 50% of single dose excreted in urine during 24 hours
 Factors influencing are
 Previous exposure to fluoride
 Age
 Urinary flow
 Urine PH
 Kidney status
 Glomerular filtration –tubular reabsorption in the form of
HF-greater the acidic urine

 PH- < 5.6: Excreted fraction of filtered fluoride <5%
Reobsorbtion-95%
 Above 5.6: increased fraction of F excretion
In acute poisoning: increased PH urine alkalizing
agents enhance the elimination of F

Via the Gut:-
 Undissolved and not absorbed excreted unchanged in feces
 10% of total fluoride intake is excreted in feces
Via sweat:-
 Varying proportions of absorbed fluoride may lost from the
body in perspiration
 Under normal conditions of F intake-concentration of Fin
sweating range of 0.07 to 0.5ppm

Via saliva:-
 Less than 1% of absorbed from saliva was recovered from saliva
 0.01 to 0.05ppm
Via breast milk:-
 0.01 to 0.05ppm
 Selective in taking up fluoride- no evidence of transfer of F from
plasma to milk
 Cow’s milk higher F content than human milk

PLACENTAL TRANSFER OF FLUORIDE
 Fluoride in primary teeth and bones: placental transfer
 Placenta does not selectively inhibit fluoride transfer
 Higher the fluoride ingestion: partial barrier may exist

Ingested fluoride
Fecal excretion
5%
50% 45 %
0.01 to 0.1 ppm
<½ of plasma F
0.067 – 0.5ppm

Fluoride supplementation
Systemic Topical
Dietary fluorides
Salt fluoride
Fluoride in sugar
Water fluoridation
School water fluoridation
Milk fluoridation
Professional application
Self
application

Water fluoridation
Definitions:-
 ‘Water fluoridation is defined as controlled adjustment of the concentration of
fluoride in a communal water supply so as to maximum caries reduction and a
clinically insignificant level of fluorosis.’
 Defined as’ upward adjustment of the concentration of fluoride ion in a public
water supply in such way that the concentration of fluoride in the water may be
consistently maintained at 1 ppm by weight to prevent dental caries with
minimum possibility of causing dental fluorosis’

• First began in Grand Rapids, U. S. A., in 1945
Studies on water
fluoridation (city)
Control
1. Grand Rapids
(Michigan)
2. Newyork
3. Brantford
(Ontario-Canada)
4. Evanston (Illinois)
5. Teil (Netherlands)
Muskegon
Kingston
Sarnia
Oak-Park
Culemberg
After 1o years -DMFT of fluoridated cities 60%
lower than the control cities

 Murray and Rugg-gunn
 compiled the status of water fluoridation globally
 using over 90 studies he compared cariostatic benefits in primary
and permanent dentition.
 Early 1960’s successful water fluoridation program –in Singapore
and Hongkong
 Backer Dricks conformed caries protection….
 Buccal, lingual and gingival smooth surface- 85%
 Interproximal surface- 75%
 Pit & fissure and occlusal surfaces- 35%
 First study on deciduous dentition in UK by Weaver in North
and South Sheilds (41%)

 Fluoride compounds used in water fluoridation-
 Fluorospar
 Sodium fluoride- most expensive source
 Silicofluoride
 Sodium silicofluoride- cheapest form
 Hydrofluorosilicic acid
 Amonium silicofluoride
 Types of equipments for water fluoridation-
 Saturation system- 4% NaF (recommended for small towns)
 Dry feeder system-NaF or silicofluoride (medium sized towns)
 Solution feeder- Hydrofluosilicic acid (large towns)

Optimal fluoride concentrations and climatic condition
 In Temperate climates (formative stages) - 1ppm
 Children living in this area- 1mg/daily
 Galagan and Vermillion emperical formula:
Based on daily fluid intake, body wt and temp
ppm F =0.34/E E = -0.038+0.0062 t
E -daily water intake in oz/lb of body wt
t- max daily temp in degrees Fahrenheit
WHO recommended (1994)- 0.5 to 1.0 ppm

• Simple modified method to
determine opt fluoride
concentration and mean annual
temp… Richard etall
oC oF Recommen
ded ppm
<18.3
18.9- 26.6
>26.7
<64.9
66.0-79.9
>80.1
1.1 - 1.3
0.8 - 1.0
0.5 - 0.7
In addition to climatic condition total fluoride intak
other than water..
Reasonable goal 60 to 65% caries reduction without f

Benefits:-
 Both pre eruptive and post eruptive effects
 Topical effect through release in saliva
 Least expensive and most effective
 “Halo effect” or “Diffusion”
Feasibility in INDIA
 Ground water btw 1 and 5mg/ml.. (21mg/ml)
 Ministry of Health Govt of India prescribed 1.0mg/ml and
2mg/ml
 1983 Nanoti & 1988 Nawlakhe given Indian standard specification
desirable limit as 0.6 – 1.2 mg/ml
 Short coming- only implemented only in areas have central pipe
water supply system.
 Only 30% of population have piped water supply

School water fluoridation
 Suitable alternative –b’cos f consumed during school days
 4.5 to 6.3 ppm- no fluorosis
 Caries reduction 45 to 50%
 Venturi system is most suitable- almost no maintainance
Advantages:-
 Effective public health measure-water supply is not possible
Disadvantages:-
 5 to 6 years old upon starting school- will not provide
preeruptive contact..
 Intermittent fluoride exposure-less than 180 days in a year

Fluoride tablets
Provides systemic effect before mineralization and topical effect after..
In deciduous dentition:-
 Caries reduction 50 -80%, started before2 years continued of 3-4 years
 Hoskova 1968(4 years)
- fluoride tab started prenatally-93%
- since birth- 54%
In permanent dentition:-
 20 to 40% caries reduction
 Longest clinical trial carried out by Aasenden and Peebles-0.5mg F tab below 3years
and 1mg thereafter—followed by 8-11 years
 mean caries75 to 80% lower

• Fluoride level in surface enamel (1-
2micrometer)
– Increased to 3000ppm
– Fluoridated water- 2300ppm
– Non fluoridated water- 1800ppm
• 0.5mgF/day –upper limit desirable level first
year of life
• Concluding that fluoride supplements during
developing dentitions results in caries
reduction than water fluoridation
Recommended dietary fluoride supplements (1999)
Age in years Concentration of fluoride in
drinking water ppm
<
0.3ppm
0.3 to
0.6ppm
>0.6ppm
Birth to 6
years
None None None
6 months-3
year
0.25mg/
day
None None

Commercially available NaF (fluoraday, tymaflour and
luride)
– 2.2 mg NaF- 1mg of F
– 1.1 mg NaF -0.5mg of F
– 0.55 mg NaF – 0.25mg of F
• Neuromuscular coordination not fully developed until
16- 18 weeks
-up to 2 years drops are preferable
• Daily recommended dose:-
– Below 2 years – 0.5mg
– 2 to 3 years -0.5 to 0.7mg
– Above 3 years- 1 to 1.5mg
Fluoride tablets: topical caries preventive agent to be
used as Dental Public Health Measure in Rural India

To enhance cariostatic effect-
 Chew and suck the tab
 Preferably at bed time..
 Continued at least until 12 to 14 years
 Should not given –water supply exceed 0.7ppm
 Should not given with milk and milk products
 Cannot replace water fluoridation –parents fail to comply with
the regimen

Salt fluoridation
 Fluoridated salt in Switzerland for the first time in 1955 (90ppm)
 90ppm -20 to 25% caries reduction
 Optimum level of fluoride in salt –Toth suggested
 Urinary fluoride excretion from salt should be similar to that obtained
from fluoridated drinking water
 200 to 350 ppm salt- 0.85 and 1.05 similar to populations ingested
fluoridated water for 10 years.
 250ppm did not achieve cariostatic effect – optimal fl content water

Advantages:-
 Low cost
 Negligible waste
 Ease of implementation
 Free choice for individual households
Disadvantages:-
 Fluoride dosages of different age in different regions
 Lower salt consumption during tooth forming years

Feasibility in India:-
 Viable and feasible method
 Easily monitored
 Effective control- supply
 Individual monitoring not required
 Freely available
 Readily acceptable- does not alter the colour

Milk fluoridation
 First mentioned by Ziegler in 1956
 Stephen et al –daily ingestion of 200ml (7ppm) for 4 years, 38.8%
reduction ( 1st permanent molar)
 Hellestrom and Ericsson—fluoride uptake by enamel from salt is greater..
Advantages:-
 Need to drink under 14 years of age
Disadvantages:-
 Incompletely ionized in milk
 Lower absorption from milk than water
 Variation in intake

 Requires parental or school efforts
 Technical difficulties
 Problem in distribution
 High cost
Feasibility in India:-
 Binding with calcium and protein in milk
 Not seem to viable and feasible
 Cannot afford milk daily
 No central milk supply system
 Variation in intake and quantity of milk

Fluoridation of flour and sugar
 Advantages requiring much less of chemical
 Fluoridation of sugar has adv –combining the culprit
and cure (difficulty to provide proper dosage)

Exception to school water fluoridation, salt
fluoridation most promising alternative to
water fluoridation.
Method Average % caries
reduction of
dental caries
Community water
fluoridation
School water
fluoridation
Dietary fluoride
supplementation
50 to 65%
40%
50 to 65%

Fluoride toxicityToxic effects of fluorides: Acute and chronic
Acute toxicity:
– Accidental contamination of food by NaF and
NaSiF salts
Certainly Lethal
Dose (CLD)
5 to 10 gm NaF
or
32 to 64
mgF/kg
Safely
Tolerated dose
(STD)
¼ CLD
1.25 to 2.5mg
NaF
or
8 to 16 mgF/kgTo prevent accidental poisoning of an infant
weighing (10kg) Council on Dental Therapeutics
of ADA recommended that: no more than 264 mg
of NaF (120mg of F) dispensed at one time

Acute poisoning:
– Causes death by blocking normal cellular
metabolism
– Inhibits enzymes causing vital functions-
Initiation and transmission of nerve impulses
to cease
– Interferences with essential body functions
controlled by calcium.
Common signs and symptoms of acute
fluoride toxicity:
Low dosages High dosages
Nausea
Vomiting
Hyper
salivation
Abdominal
pain
Diarrhea
Convulsions
Cardiac
Arrhythmias
Painful
spasms
Paresis

 Death usually results: cardiac failure or respiratory failure
Serious symptoms : with in 1 to 2 hours after ingestion
Death occurs from 2 to 4 hours after ingestion
 Nausea and vomiting : dose 30 t0 80 mg of NaF
 Vomiting diarrhea and severe abdominal pain: 100mg NaF
 Gastrointestinal symptoms: corrosive effect on gastric mucosa by
HF acid
Treatment : administration of calcium or magnesium or
aluminum salts

CHRONIC TOXICITY
Fluoride level Water consumption Effects
0.7 to 1.2 ppm
1.5 to 3.0ppm
3.0 to 8.0ppm
8.0ppm or more
Depending on temp of
area
Period of 5 to 10 years
15 to 20 years
5 to 10 years
Prevents dental caries
Mild dental fluorosis
Severe dental fluorosis
Mild skeletal fluorosis
Severe form of dental
skeletal fluorosis

DEFLUORIDATION
• Defluoridation means to improve the quality of
water with high fluoride concentration by
adjusting the optimal level in drinking water
– Absorption and ion exchange method:-
exchange negative ions such OH- group for fluoride
ions depends up on PH, temperature, flow rate, grain
size of the material
common used materials: activated alumina, activated
bauxite, Zeolite, Tricalcium phosphate, activated bone
char, magnesite, magnesite etc

 Precipitation method:-
In a high PH condition, co-precipitation of
several elements in water with fluoride ions forms
fluoride salts- flocculation (Aluminum ions)
 Alum
 Alum and lime
 Lime softening
 Calcium chloride

Membrane separation
• Reverse osmosis process
• Expensive developing countries
• 30% of raw water is lost in the process

INDIAN TECHNOLOGY FOR
DEFLUORIDATION
• Nalgonda Technique:
India in 1975
most simple
least expensive
Easiest to operate

Fluoride water
Supply Disinfection Filtration
settlingFlocculation
Alum
NALGONDA TECHNIQUE

NALGONDA TECHNIQUE:-
Advantages:
– domestic and community levels
– manually possible
– cost effective
– flexible design to use in different location

PRASHANTHI TECHNOLOGY
• Activated Alumina- most popular
cost effective
Bio-Science, Department of Sathya Sai
University of Higher Learning in
Prasant Nilayam

OTHER METHODS TRIED IN INDIA
• Fish bone charcoal- University of Roorkee
• Drumstick Moringa cleifera- Reduce water turbidity
-calcium and magnesium levels in plants
• Askali- extract mycetial biomass-Osmania university
Aspergillus riger
• Clay materials-Montmosllonite KSF, Kaolin and a Silty
Clay Sediment series
• Tricalcium phosphate(TSP)

REFERENCES :-
• Text book of pedodontics- SHOBA TANDON
• Fluorides and Dental caries- AMRIT TEWARI
• Pediatric dentistry- STEWART
• Essentials of preventive and community dentistry-
SHOBAN PETER
• Pediatric dentistry: STEPHEN WEI
• Fluorides in caries prevention- J.J. MURRAY

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