Systemic fluorides, water fluoridation and fluoride metaboli

FLUORIDES
Fluoridemetabolism
Systemic fluorides
INDIAN DENTAL ACADEMY
Leader in continuing Dental Education
www.indiandentalacademy.com

contents
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 www.indiandentalacademy.c
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Cont…
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 www.indiandentalacademy.c
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Introduction
www.indiandentalacademy.c
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Historical evolution of fluorides-
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 dentalwww.indiandentalacademy.c
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Historical evolution of fluorides…
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….
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Historical evolution of fluorides…
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’
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Fluoridechemistry & 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
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Reasons for high reactivity:- 1s2
, 2s2
, 2p5
Most electronegative of all elements
Small size of atom
High electron affinity
Small bond length
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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%
occurrence-
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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
occurrence -
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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
occurrence-
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Total daily intakeof 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
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Total daily intakeof fluoride…
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
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Fluoridemetabolism & 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 mucosalwww.indiandentalacademy.c
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Fluoridemetabolism & Bioavailability…
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 www.indiandentalacademy.c
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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 www.indiandentalacademy.c
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Physiologic Distribution of fluoride…
Fluoride in soft tissue:-
Tissue/ plasma ratio = 0.4 to 1
Ectopic calcification loci- F accumulation in Aorta,
tendon, cartilage and placenta
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Effectson 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
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Fluoridein hard tissue
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
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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
Fluoridein hard tissue…
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Fluoride concentration in the outer enamel (2micrometer)-
1700ppm-non fluoridated areas (0.1ppm)
2200 to 3200ppm- optimally fluoridated areas (1ppm)
4800ppm- 5 to 7ppm
Depth 5 micrometer-
Permanent
teeth
Primary teeth
Non-
fluoridated
areas
Fluoridated
1100ppm
2200ppm
670ppm
950ppm
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F concentration in newly erupted teeth- higher in in
incisal than cervical margin
Diffusion of F in enamel NaF and
monoflurophosphate(100pmm)-
10-9
cm2
/sec
Speed at which F penetrates in enamel-
38 micrometer/ hour (186micrometer/ day)
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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
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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
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Mechanism of action of fluoride in
cariesreduction.
Increased enamel resistance (or)
reduction in enamel solubility
Increased rate of post eruptive
maturation
Remineralization of incipient lesions
Interference with plaque
microorganismswww.indiandentalacademy.c
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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
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Enamel fluorosis…
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
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Criteriafor Diagnosisof 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
frequentwww.indiandentalacademy.c
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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
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Osteofluorosis…
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 painwww.indiandentalacademy.c
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Soft tissuefluorosisarewe
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) www.indiandentalacademy.c
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Soft tissue fluorosisarewe
neglecting????
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)
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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 urinewww.indiandentalacademy.c
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Excretion of fluoride…
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
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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 0.5ppmwww.indiandentalacademy.c
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Via saliva:-
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
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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
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Ingested fluoride
Fecal excretion
5%
50% 45 %
0.01 to 0.1 ppm
<½ of plasma F
0.067 – 0.5ppm
PLASMA
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9.9
40
7
10- 15
21
15
11
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Fluoride supplementation
Systemic Topical
Dietary fluorides
Salt fluoride
Fluoride in sugar
Water fluoridation
Milk fluoridation
Professional application
Self
application
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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
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Water fluoridation…
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 www.indiandentalacademy.c
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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%)
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Fluoride compounds used in water fluoridation-
Fluorospar
Sodium fluoride- most expensive source
Silicofluoride
Sodium silicofluoride- cheapest form
Hydrofluorosilicic acid
Ammonium silicofluoride
Types of equipments for water fluoridation-
Saturation system- 4% NaF (recommended for small
towns)
Dry feeder system-NaF or silicofluoride (medium sized
towns)
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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
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Simple modified method to determine opt
fluoride concentration and mean annual temp…
Richard et al
o
C o
F Recommend
ed 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
n addition to climatic condition total fluoride intake from sources
ther than water..
Reasonable goal 60 to 65% caries reduction without fluorosis
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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 has given Indian
standard specification desirable limit as 0.6 – 1.2
mg/ml
Short coming- implemented only in areas have central
pipe water supply system.www.indiandentalacademy.c
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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 awww.indiandentalacademy.c
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Fluoridetablets
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
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Fluoridetablets…
Fluoride level in surface enamel (1-2micrometer)
Increased to 3000ppm
Fluoridated water- 2300ppm
Non fluoridated water- 1800ppm
0.5mgF/day –upper desirable limit 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/d
ay
None None
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Fluoridetablets…
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
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Fluoridetablets…
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
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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
om

Salt fluoridation…
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 www.indiandentalacademy.c
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Salt fluoridation…
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
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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
MILK
FLUORIDATION
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Milk fluoridation…
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
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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)
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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%
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Fluoridetoxicity
Toxic 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
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AcuteFluoridetoxicity…
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
Parathesia
Convulsions
Cardiac
Arrhythmias
Painful spasms
Paresis
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AcuteFluoridetoxicity…
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
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Chronic toxicity
Fluoride
level
Water consumption Effects
0.7 to 1.2
ppm
1.5 to
3.0ppm
3.0 to
8.0ppm
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 skeletalwww.indiandentalacademy.c
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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
materialwww.indiandentalacademy.c
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Defluoridation…
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
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Membraneseparation
Reverse osmosis process
Expensive developing countries
30% of raw water is lost in the process
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Indian technology for defluoridation
Nalgonda Technique:
India in 1975
most simple
least expensive
Easiest to operate
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Fluoride water
Supply Disinfection Filtration
settlingFlocculation
Alum
NALGONDA TECHNIQUE
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NalgondaTechnique:
Advantages:
domestic and community levels
manually possible
cost effective
flexible design to use in different location
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Prashanthi technology
Activated Alumina- most popular
cost effective
Bio-Science, Department of Sathya Sai
University of Higher Learning in
Prasant Nilayam
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Other methodstried 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 serieswww.indiandentalacademy.c
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ANTI FLUORIDE LOBBY…………………..
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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. MURRAYwww.indiandentalacademy.c
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Systemic fluorides, water fluoridation and fluoride metaboli

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Systemic fluorides, water fluoridation and fluoride metaboli