Fluoride Introduction and History

Introduction &History of
Flourides
Dr. Naseemoon Shaik
Final year M.D.S
J.S.S.D.C.H.

 Latin “fluor”- to flow or flux.

 Because of the small radius of the Flouride atom, its
effective surface charge is greater than that of any other
element.
 Thus, it is the most electronegative and reactive of all
the elements- reacts promptly with the surroundings
and is rarely in the elemental state.
 Flouride frequently occurs in nature in its inorganic
form.
Flourides in Dentistry. Fejerskov, Ekstrand and Burt. 2nd Edition.

 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%

 1973- Fluoride has been described as an essential nutrient
in the Federal Register of united states Food and drug
Administration ,and by WHO committee on trace
elements and human health who have included fluorine in
its list of 14 trace elements ,recognised to be physiologically
essential for the normal growth and development of human
beings.

 Fluorine was discovered by chemist
Scheele in 1771.
 In 1802 , Morozzo described a fossilised
elephant , a couple of years later fluoride
content in this animals tooth was
determined.
 In 1805, Morichini found fluoride in human
Enamel.
 Desirabode in 1847 referred to fluates-
(silicate or fluateof lime and alumine, dried
and pulverized)
Scheele

Berzelius, 1822: suspected that Flouride was present in
water.
Wilson, 1846: reported the presence of Calcium flouride in
one of the wells of Edinburgh.
Wilson, 1846: reported an experiment on the hard crust that
collects at the bottom and sides of the boilers used in the
evaporation of sea water.
He concluded by stating that, "if flouride be present in the
waters of Firths of Forth and Clyde, and in the German
Ocean, it will be present universally in the sea."

 1847- Ficinus , reported his belief in the presence of
fluoride in enamel and dentine
 1855- Fremy found fluoride in fresh bones, bone
powder and bone ash.
 First reference to prophylactic role of fluoride
made by Erhadt in 1874

 Moissan, 1886: First to isolate Flouride.
 Hillebrand, 1893: First to report the concentration
of Flouride in drinking water in ppm, i.e, 5.2 ppmF
in water from a thermal spring in New Mexico.
 Dr A. Denninger (1896)- Fluoride an agent to
combat dental disease and Appendicitis

 He gave a lecture entitled ' Flouride: an agent to combat
dental disease and perhaps also appendicitis.' He
summarised-
 Most often, flouride in the diet is not enough for dental
beneficial effects
 Children in their early years and pregnant women and their
unborn children do indeed benefit from the regular intake of
calcium flouride.
 It is adviced to have 100g of finely powdered Flourspar, first
daily for 2 weeks, then once in 2-4 days and later over longer
intervals.

 In 1902, Cross & co., Copenhagen Denmark, pusblished a
pamhlet titled, ' Flouridens: How to Remedy the Decay of
our Teeth.' (Tablets contained 83.7% calcium flouride)
 In England, this prep was mixed with table salt in the
proportion 1 teaspoon Flouridens to 2 teaspoons salt.
 the pamphlet ellaborated that the decay of teeth was
due to the use of refined foodstuff and lack of flouride
in the diet.

 In 1908, the British Dental Journal, under the
heading 'Calcium flouride in therapeutics' gave an
abstract on flouride dosages.
 The article referred to the beneficial effects of
flouride toward bones and teeth.
 Brissemort, 1908: reported that the administration
of 5 mg Calcium flouride , 15 days a month, had a
marked influence in arresting dental caries.

 Thus, it can be said that the use of flourides for
dental purposes began in the 19th century, with the
first entirely speculative ideas leading to the
development of F-containing pills in the 1890s.
 This aspect of flouride and dental health then lay
dormant for over 40 years.

 It is more than 80 years old and started with the
arrival of Dr. Frederick McKay in Colorado springs,
Colorado, USA in 1901.
 He soon noticed that many of his patients had an
apparently permanent stain on their teeth, which
was known locally as, 'Colorado Stain'

 He called the stain 'mottled enamel' and characterised it as :
" Minute white flecks, or yellow or brown spots or
areas, scattered irregularly or streaked over the
surface of the tooth, or maybe a condition where
the entire tooth surface appeared dead paper-
white, like a china-dish.“
1905 : McKay moved to St Louis to practice Orthodontics and
stayed there for 3 years during which he never saw a single
case of Mottled enamel, whereas, at Colorado he saw such
cases every day.

 When he returned to Colorado in 1908, his
curiosity about the stain problem recovered in full
force and he presented one case of the stains at the
State Dental Association in Boulder.
 He found that similar conditions were present in
several other towns as well.

 McKay decided that to gain the interest and
attention of the dental fraternity, he must get help
from a recognized dental research worker. Thus, he
approached Dr. G.V. Black, pioneer in dental
enamel lesions.
 At first Dr. Black thought McKay was mistaken, he
soon learned that the facts were irrefutable and
that the widespread prevalence of such lesions in
certain endemic areas needed to be recorded and
investigated.

Dr. McKay and Dr. Issac Binton, examined the children in
primary schools in Colorado springs region and were
astonished to notice that 87.5% children showed mottled
enamel (2945 investigated).
This data was presented to Black when he arrived in Denver
in 1909 to tour the Colorado springs area.
In 1912 Mc Kay came across an article by Dr. J.M Eager (1902)
reported that a high proportion of italian residents in
Naples had ugly brown stains on their teeth known as
“Denti di chiaie”

 Black addressed the State Dental Association meeting on
the histological findings and also published a paper in 1916
titled, 'An endemic imperfection of the enamel of teeth
heretofore unknown in the literature of dentistry.'

 Despite Black's involvement, interest in the Colorado
stains died down quickly and McKay decided that he
would investigate other endemic areas where such
stains were seen.
 In response to Dr. Black's article in a newsletter,
Dental Brief, Dr.W.H Arthur, wrote a letter to the
newspaper describing a similar condition in one of the
seaward Southern states. McKay contacted him and
summarised that the stains were indeed identical.

 Another dentist, Dr. Rice, reported a similar stain at
Smavillo, Texas and donated 2 incisor teeth for
analysis(mottled enamel)
 Dr. Joseph Murphy, greatly helped McKay to examine and
report the presence of mottling among Indians in all
schools under his jurisdiction.
 In 1912, McKay realized that the stains were not restricted to
USA, when he came across an article by Dr.J.M. Eager,

 1916 -McKay and Black examined 6,873 individuals in 26
communites in USA and reported that unknown causative
factor of motteled enamel was possibly present in domestic
water during the period of tooth calcification .
 Histological investigations showed that mottling was due to
failure of the cementing substance of the enamel.
 McKay realised that this poorly calcified, imperfect enamel
should be more susceptible to caries, but, on the contrary, he
was struck by the fact that caries was no higher in mottled
teeth.

 McKay's summaries:
 occarrence was restricted to certain specific geographic(endemic) areas.
 only children who had been born and who lived their whole lives in
that area showed the motlling. Chlidren who had moved to the area at
the age of 2-3 years didn't show mottling.
 condition was not affected by home or environmental factors
 affected the rich and the poor(ruled out dietary causes)
 Three cities in Arkansas showed mottling and were several miles apart
but shared a common water source, Fountain Creek

 Thus, McKay concluded that the cause had to be related to the
water supply in some way.
 Further evidence for the water-supply hypothesis came when
another dentist, Dr. O.E. Martin(1916) stated that similar stains
were surfacing in the town of Britton, South Dakota(1989) after
the water supply in the region was changed from individual
shallow wells to a deep-drilled artesian well.
 These stains were seen only in children born and raised after the
switching of the water supply.

1908: The small town of Oakley, Idaho changed its water
supply to a warm spring 5 miles out of town and in the
following years, mottling was noticed and became so rampant
that by 1923, the concerned mothers of the town appealed to
the local authorities, with the help of the Dentists to change
the water supply.
Based on the limited information available, McKay advocated
a switch to Carpenter spring water supply and by February
1933, 24 children in Oakley showed no mottling in their newly
erupted permanent teeth.

 Similar occurrence :1909- Bauxite-changed the water supply
from shaloo wells to a deep-seated common well-mottling
observed by a dentist of the nearby town of Benton, Dr. F.L.
Robertson.
 McKay studied the water but stated that water analysis of the
Bauxite water threw little light on the probably causative agent.

 Mr. H.V. Chruchill, the chief chemist of the Alluminium
company of America, was disturbed by the news about
Bauxite water as most of the alluminium came from Bauxite
and there were rumours that alluminium-ware was not
appropriate for cooking.
 He instructed Mr. A.W. Petrey, head of the testing division to
look for traces of rare elements(usually not looked for) and it
was noted that flouride was present at the level of 13.7
ppm.(1931)

 Mr. Chrchill wrote to McKay about the results and urged him to
test the waters of all the endemic areas for Flouride. The results:
Even then, no precise correlation between the mottling and the
flouride content of the water was established.
Location Fouride (ppm)
Deep well, Bauxite 13.7
Colorado Springs 2.0
Well near Kidder, South Dakota 12.0
Well near Lidgerwood, South Dakota 11.0
Oakley, Idaho 6.0

Confirmation of Churchill's findings came when Dr.Margaret
Smith and her husband, Mr. Howard Smith (1931), from the
Arizona Agricultural dept, observed mottled enamel among
the residents of St Davidand decided to produce mottled
enamel experimentally in rats.
They concentrated the st David water to 1/10th of its original
volume by boiling and fed it to the rats.
Within a week, the rats' incisor teeth showed lack of
translucency and within a month, visible mottling set in.

 The Arizona workers then fed Sodium flouride to rats in
varying concentrations and noticed that the enamel defects
so produced were strikingly similar to those produced upon
consumption of the St David water.
 This led them to test the water, which revealed a flouride
concentration of 3.8-7.2 ppm.
 Thus, confirming the hypothesis that the mottling could
indeed be attributed to the high flouride content in the water.

 Dr. Norman Ainsworth, a dentist based in Middlesex
Hospital in 1921, noticed a young girl, aged 15, showing signs
of curiously opaque teeth with brownish black stains. She
was from Maldon, Essex.
 He inspected the town of Maldon when he undertook a tour
for the Dental Diseases Committee and examined several
school children in England and Whales.
 He noted that the percentage of caries experience was lesser
among Maldon children(13.1% vs 7.9%) and among the 134
children of Maldon, 125 showed mottling(1925).

 Ainsworth, 1933: (after reading Black and Mckay's 1916 article)
'the similarity between my own description and theirs is so
striking in every detail as to leave no reasonable doubt that
the conditions were identical.'
 The significance of Ainsworth's contribution is that he gave
statistical data showing that the caries experience in a floride
area was lower than average, in addition to McKay's
observation that the caries rate was no higher than the normal
teeth.

 Dr. Clinton Messner, head of the US Public Health Service, in
1931, assigned a young dental officer, Dr.H. Trendley Dean, to
pursue full-time research on mottled enamel.
 His first task was to continue McKay's work and find the
extent and geographical distribution of mottled enamel in
USA.
 He sent a questionnaire to every local and state dental society
in the country asking if mottled enamel existed in their area,
if so, how extensive was it and the source of the drinking
water supply.

 As a result of this investigation, Dean reported 97 localities in
the country where mottled enamel was said to occur and this
claim had been confirmed by a dental survey.
 A further 28 areas were metioned in the literature to be
endemic areas of flouride but no surveys had the been done
and another 70 areas had been reported by questionnaires but
extensive dental surveys were yet to be done.

 Most of these confirmatory surveys was done by Dean himself
and he and his collegues called the survey as the 'shoe leather
epidemiology'.
 Dean, 1934: Developed a standard for classification of mottling
in order to record the severity of mottling within a community,
so that he could relate the flouride concentration of the water to
the severity of mottling seen.

 Dean and Elvove, 1936: presented evidence to prove that
amounts of Flouride not exceeding 1 ppm were of no public
health significance.
 2nd Oct, 1938: along with Dr. McKay, he summarised the
knowledge of mottled enamel in a paper to the
Epidemiological Section of American Public Health Assoc.
and reported that there were 375 known areas, in 26 states,
where mottled enamel of varying of severity was found.

 Dean and McKay, 1939: stated that the production of
mottled enamel had been halted in Oakley, Idaho, Bauxite,
Arkansas and Androver, South Dakota, simply by changing
the water supply to one that did not exceed F conc of 1ppm.
' The most conclusive and direct proof that flouride in the
domestic water is the primary cause of human mottled
enamel.'
McKay's search for the cause of mottled enamel beginning at
Colorado springs(1902) was finally successfully completed
after almost 40 years.

 Dean had read both, McKay's and Ainsworth's work on the
relation between caries occurrence and flouride exposure.
 During the survey, Dean had also examined the children for
dental caries and concluded that among 9-year-old
children, 114 children who had continuously used domestic
water low in F(0.6-1.5 ppm) only 4-5% were caries free.
 Whereas, among 122 children who had been drinking
domestic water containing 1.7-2.5% F , 22% were caries-free.

 Dean, 1938: ' In as much as it appears that the mineral
composition of the drinking water may have an important
bearing on the incidence of dental caries in a community, the
possibility of partially controlling dental caries through the
domestic water supply warrants thorough epidemiological-
chemical study.'

 This study was planned to test the previously mentioned
hypothesis
 The cities were, Galesburg and Monmouth( water containing
1.8 and 1.7 ppm F resp) and the nearby cities of Macomb and
Quincy(0.2 ppm F)
 885 12-14 year old children were examined and the results were
clear in that the caries experience of those from Macomb and
Quincy were twice as high as of those from the other 2
cities.(Dean et al, 1939)

 Conducted by Dean, Arnold and Elvove.
 This study laid the basis for the choice of 1.0 mg F/L as the optimal
concentration for flouridation.
 7257 12-14 year olds were examined from 21 cities in 4 states.
(Illinois. Ohio, Indiana, Colorado)
 It was found that,
 at 0-0.2 ppm F : DMFT was 6-10
 at 1 ppm F : DMFT was 2-3

 Thus, they concluded that maximal reduction of caries
experience occured with a concentration of 1 ppm F in drinking
water. At this concentration, only 'sporadic instances of the
mildest form of dental flourosis of no practical aesthetic
significance' was noted.

 A naturally flouridated area was discovered as a result of children
being evacuated from an industrial area because of WW II.
 Dr. Robert Weaver(Dentist in the Ministry of Education), 1941:
was told by Mr. Irwine, a senior School Dentist for Westmorland,
that children evacuated to the Lake District from South Sheilds,
on the mouth of the River Tyne, 'had remarkably good teeth-
much better than those of the local children'.

 Weaver visited Westmorland and examined 117 evacuees
(approx 11 years old) and found that the mean DMFT was
1.7.(1944)
 On Weaver's insistance, Dr. Dawson, North Shields and Dr.
Campbell, South Shields(on either sides of River Tyne),
analysed their respective water supplies for Flouride.
 North Shields- less than 0.25 ppm; South Shields- around 2
ppm.

 Subsequently, Weaver (1944) examined 1000 children on
either side of River Tyne.
 Mean DMFT of 5 yr olds:
 North Shields : 6.6
 South Shields : 3.9
 Mean DMFT of 12 yr olds:
 North Shields : 4.3
 South Shields : 2.4
 His study was important as he focussed attention on both
deciduous and permanent dentition.

 After the 21 cities survey, the work on flourides came to a halt,
due to WW II.
 Studies on dental caries prevalence in artificially flouridated
areas:
 Grand Rapids-Muskegon
 Newburgh-Kingston
 Evanston-Oak Park
 Canadian studies
 Dutch study(Tiel-Culemborg)
 New Zealand study(Hastings)
 British studies

 The crucial step was to determine if dental caries could be
reduced in a community by adding flouride at 1 ppm to a F-
deficient water supply.
 In December 1942, the US Public Health Service began talks
with officials from two cities in Lake Michigan area, Grand
Rapids and Muskegon.
 Moulton, 1942: Not only was a F conc of 1 ppm the best for
caries control, it was also well within the safety limits.

 Both city councils agreed in August 1944, to conduct the
experiment under Dr. Dean. Grand Rapids would be the
experimental town and Muskegon, the control.
 Sept 1944: Dean, Arnold, Jay and Knutson began the
examination of 19, 680 Grand Rapids children and 4291
Muskegon children aged 4-16 yrs. Baseline studies showed the
caries experience of the primary and permanent dentition of
the children of both the cities were similar.
 5116 children native to Aurora, Illinois(F=1.4 ppm) were
examined to provide further baseline data.

25 th Jan 1945: Historic day as it was the first time that a
permissible quantity of a beneficial dietary nutrient was
added to the communal drinking water.(NaF)
Arnold, Dean, Knutson, 1953: after 6.5 yrs of flouridation in
Grand Rapids- caries experience of 6 yr old Grand Rapids
children was almost half of that of the Muskegon children.
Muskegon city authorities, convinced of the efficacy of
flouridation, began flouridating their own water supply
from July 1951 and since the, have not been a control city.

 DMFT of 15 yr old Grand Rapids children: 1944=12.48 and
1959=6.22( almost 50 % reduction)
 The caries experience in the flouridated community of
Grand Rapids was similar to that occuring in naturally
flouridated Aurora.
 Knutson later said that, they had by then realized that the
ideal amount of Flouride needed was 1 ppm and hence,
went ahead with subjecting 1,60,000 people to a procedure
which might have had short or long term hazards.

 2nd May, 1945: NaF was added to the drinking water
of Newburgh, on the Hudson river. Study was directed
by David B., Asst Chief of the Dental Bureau, New
York State Dept of Health.
 Baseline studies were carried out in 1944-46 (similar
caries status) and clinical examination 10 yrs
later(1954-55) revealed that the caries experience of
10-12 yr olds in Kingston had changed little(23.1% to
26.3%), while Newburgh children showed DMFT
fallen fron 23.5% to 13.9%.

 3rd American flouridation experiment-Jan 1946.
 Evanston:Test and Oak Park: Control
 Dr. Blayney, Dr. Hill and Dr. Zimmerman conducted the study
and their findings after 14 yrs of flouridation (Blayney and Hill,
1967) stated that , while the DMFT values of 14 yr old Evanston
children fell from 11.6% to 5.95% between 1946 and 1960, no
change was observed among Oak Park children.
 This study presented the most detailed data of all flouridation
studies.

 Study was conducted by- Hutton, Linscott and Williams, 1951
and Brown and Poplove, 1965.
 Flouride was added to the water supply at Brantford: June 1945.
 Sarnia was the control town and Stratford was a naturally
flouridated community(1.3 ppm F)
 After 17 yrs of flouridation, caries experience in Brantford was
similar to that at Stratford and 55% lower than Sarnia.

 Conducted by:Backer Dirks, Houwink and Kwant
 The caries inhibiting activity of flouride in drinking water is not
uniform: it inhibits smooth surface caries much more than pit and
fissure caries.
 The Dutch study(1953) was focused on investigating this selective
property.
 The study was designed to assess the preventive effect of F drinking
water on the anatomical siting of caries attack: approximal, pit and
fissure etc.

 March 1953: drinking water of Tiel was flouridated to 1.1 ppm,
while Culemborg, at F conc 0.1 ppm was control.
 Baseline examinations of 11-15 yr olds showed no significant
differences between the 2 cities.
 Examination in 1969, on 15 yr old children who had been born
within a year of flouridation of the water.
 135 Culemborg 15 yr olds: 25.8 carious sites/surfaces
 147 Tiel 15 yr olds: 11.3 carious sites/surfaces(56% red.)

Percentage reduction in:
smooth surface caries: 86%(highest)
pit and fissure caries: 31%
approximal caries: 75%
number of teeth extracted due to caries: 85% less in Tiel kids

 Kwant et al, 1974: reported the life-long effect of water
flouridation on 17 and 18 yr olds, stating that there was 53%
and 48% reduction in cavity formation among 18 and 17 yr
olds in Tiel when compared to Culemborg children
respectively.
 The epidemiological evidence from this study indicated that
adequate ingestion of flouride at an early stage of enamel
formation is important in preventing P&F caries, but is of less
importance as far as smooth-surface caries is concerned.

 This was a retrospective study by Ludwig.
 Baseline study was carried out in 1954, re-evaluation after 10
yrs(1964) and 16 yrs(1970) of flouridation revealed a fall in
DMFT from 16.8 in 1954 to 8.5 in 1970 (49% reduction).
 This study also demonstrated a selective caries-inhibitory
action of F on different tooth surfaces.
 Smooth surface caries: 87% reduc.
 approximal caries: 73% reduc.
 occlusal surface caries: 39% reduc.

 Weaver in 1944- North and South Shields study
 Weaver, 1950: carried on a 2nd investigation in North-East England,
including a survey of West Hartlepool children, where F content
was 2 ppm.
 He stated that among 500 5 yr olds, the dmft was 1.76 and that
53.4% children were caries-free.
 500, 12 yr olds- DMFT wa 0.96 and 59.8% were caries-free.
 Conclusion:'There can be few, if any, other areas in this country
where the avg DMFT of 12 yr olds was less than 1.'

 Forrest, 1956: 324 12-14 yr olds in different parts of England
with F conc betweem 0.9-5.8 ppm was compared to 259
children of the same age from non-flouridated areas.
 She concluded by stating that caries prevelence was markedly
lower in the flouridated regions.

 James, 1961: 1027 children 11-13 yrs from 3 areas in East Anglia,
Norwich and Yarmouth(Norfolk)(F= 0.17-0.2 ppm),
Chlemsford (Intermediate F content) and Colchester(F= 1.2-2
ppm)
 Colchester children were further devided into 'continuous'
and 'non-continuous' residents.
 DMFT of children continuously residing in the high-flouride
area was less than half that of the corrsponding children
living in low F areas.

1952: British Govt sent a mission to US and Canada to study
flouridation in operation and they consluded that
flouridation of water supplies was a valuable health measure,
but recommended that in Britain, F should be added to the
water supplies of certain selected communities before its
general adoption is considered.
Communities chosen: Watford, Kilmarnock and part of
Anglesey-F added in 1955-56.
Sutton, Ayr and the rest of Anglesey=Control towns.

 Result after 5 yrs of Flouridation(1962): caries experience of 5
yr-old children was 50% lower in the Flouridated areas than
others.
 In spite of this, flouridation was discontinued in Kilmarnock
in 1962 but the caries experience was assessed after 11 yrs of
flouridation: concluded that flouridation of water supplies
was indeed a highly effective method of reducing dental
caries.

 Ireland: water flouridation has been mandatory since 1964
 UK: decision to flouridate water is taken up by the local
authorities, and in 1971, approx 5% of the total population
had the benefit of flouridated water which doubled by 1980.
 Scotland: 1977, Strathclyde Regional Health authority voted
to introduce water flouridation to West Scotland but after a
long court case ruled that it was ultra vires.

 Water flouridation Bill was passed in 1985 and the law
was changed but the flouridation schemes stopped
have not been restared in Scotland.
 Approx 6.5 million people in England and Wales
consume water containing 0.7 ppm or more flouride.

 Increasing prevalence of dental caries, developing
economy of our country, dentist population ratio and lack
of preventive awareness of oral diseases, communal water
fluoridation appears to be the most effective, practical
and economical public health measures for prevention of
dental caries as this measure extendeds its benefit to all
the residents of the community without necessitating any
consious effort on the part of the residents.

 Currently most of the cities and towns in India covering
30% of the population have piped water supply.
 School water fluoridation
 Systemic administration of fluorides
Fluorides and dental caries . A compendium:Amrit Tewari,Ved Prakash Jalili.

 Fluorides in caries prevention : JJ Murray, A.J Rugg-Gunn,G.N
Jenkins :3rd edition.
 Flourides in Dentistry. Fejerskov, Ekstrand and Burt. 2nd
Edition.
 Fluorides and dental caries . A compendium:Amrit
Tewari,Ved Prakash Jalili.
 The Fluoride Wars: How a Modest Public Health Measure
Became America's Longest-Running Political Melodrama R.
Allan Freeze ,Jay H. Lehrh
 Images from google

Fluoride Introduction and History

Fluoride Introduction and History

In this document