Download Fluoride and Prevention

Fluoride and Caries
Prevention in Children
Brief History of Fluoride and
Preventive Dentistry
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In 1909, a young dentist in Colorado
Springs Colorado, Dr. Frederick McKay
made the observation that a large number
of his child patients had a brown stain on
their teeth, in some instances disfiguring.
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However, the teeth that were stained
appeared to be resistant to dental caries.
The Colorado Dental Association invited
G.V. Black, the distinguished dental
educator at Northwestern University to
speak at their annual convention and to
investigate the brown stain that has been
identified by Dr. McKay.
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Black could not believe the circumstance
had not previously been reported in the
dental literature. He spent the remainder of
his six years of life studying it.
Brief History of Fluoride and
Preventive Dentistry
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Staining came to be known as
Colorado Brown Stain.
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In 1923, the community of Oakley,
Idaho, invited Dr. McKay to consult
with them regarding brown stain that
had recently begun appearing on
their children’s teeth.
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The source of the community water
supply of Oakley had recently been
changed; McKay was suspicious of
a water-borne causation.
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He recommended a change in the
source of the community’s water
supply.
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After the source was changed, the
brown stain subsequently
disappeared.
Brief History of Fluoride and
Preventive Dentistry
• In the late 20s, Dr. McKay was
asked to visit Bauxite, Arkansas,
as the same brown staining of
children’s teeth was occurring.
• Bauxite was a ‘company-town’ of
the Aluminum Company of
America.
• McKay investigated with a USPHS
dentist and reported findings.
However, could not identify
anything in the water.
• In 1933, an Alcoa aluminum
chemist, H.V. Churchill, using
photospectrographic analysis
identified that the substance in the
water supply was fluoride.
Brief History of Fluoride and
Preventive Dentistry
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Fluoride is a ubiquitous element in
earth’s crust; the 13th most
abundant element. Image is of
fluorite mineral crystal.
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Increases in fluoride correlate
with increased depth.
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Deep artesian wells, common in
Rocky Mountain Range and
extending into Mexico, result in
more fluoride in the water.
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Fluoride is also by-product of
aluminum production. Bauxite,
Arkansas’ public water intake was
downstream from the waste water
disposal of the aluminum
company.
Brief History of Fluoride and
Preventive Dentistry
• Fluoride is ubiquitous, found naturally in low
concentration in essentially all drinking water and
foods.
• Waters from underground sources are more likely
to have higher levels of fluoride; the concentration
in seawater averages 1.3 parts per million (ppm).
• Fresh water supplies generally contain between
0.01–0.3 ppm.
Brief History of Fluoride and
Preventive Dentistry
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H. Trendley Dean of the National Institute of
Dental Research is credited with first fluoride
studies.
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By 1936, it had been determined that fluorosis
does not occur at levels under 1.0 ppm.
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However, caries preventive effect observed at
1.00 ppm.
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Subsequent recommendations led to adding
varying parts per million fluoride to the water,
from 0.7-1.3 ppm, depending on average daily
temperatures. Assumption was that people in
hotter climates drink more water, therefore need
to reduce fluoride concentration in the water..
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Recently, recommendation was reduced by the
CDC from an average of 1.0 ppm to 0.7 ppm,
based on concern regarding increasing
prevalence of fluorosis.
Water Fluoridation
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In 1945, Grand Rapids, Michigan
added fluoride to its public water
supply, the first community in the
world to fluoridate its public water
supply.
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Over next fifteen years fluoridation
was studied extensively by NIH.
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Eight cities were involved as
experimental and controls: Grand
Rapids and Muskegon, Michigan;
Newburgh and Kingston, New
York; Evanston and Oak Park,
Illinois; and Brantford and Sarnia,
Ontario, Canada.
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Documented that adding fluoride
to water supply reduced dental
caries by 50-60%, and was safe.
Developmental Changes in Enamel
in the Presence of Fluoride
• Hydroxyapatite is the crystalline form of enamel
with the formula Ca10(PO4)6(OH)2.
• In the presence of fluoride (from fluoridated water)
during tooth development, the OH- ion is replaced
by the fluoride ion, producing fluorapatite.
• Fluorapatite is more resistant to acid
demineralization than is hydroxyapatite.
• It has also been determined that teeth developed
in the presence of fluoride (with fluorapatite
formed) have more well-coalesced grooves on the
occlusal surfaces and fewer pits and fissures.
Water Fluoridation
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For 70, community water fluoridation has been a safe and
healthy way to effectively prevent tooth decay. Centers for
Disease Control has recognized water fluoridation as one of
the 10 great public health achievements of the 20th century.
Average cost savings ranges from $15.95 per person per
year in a small community to $18.62 per person per year in a
larger community.
Costs to fluoridate average $.95/person/year.
72% of public water supplies are fluoridated; 75% of
Americans drink fluoridated water.
Kentucky was first state in U.S. to mandate fluoridation of all
public water supplies.
Major cities without the benefit of water fluoridation include:
Portland, San Jose, Wichita, Albuquerque, Tucson, and
Fresno.
With advent of use of fluorides in dentifrices. professional
applied topical fluorides, and other vehicles the relative
reduction is dental caries is now approximately 25%, versus
the earlier reduction when fluoridation was the only vehicle.
Supplemental Systemic Fluorides
• As not all individuals have access to public water supplies and not
all public water supplies are fluoridated, fluoride tablets were
developed for ingestion by children during the period of tooth
formation.
• While use of supplemental fluorides was popular for several years,
they are fairly infrequently used today.
• The research has not been consistent as to their effectiveness.
• Additionally, dosage was difficult to control as allowances had to be
made for the amount of naturally occurring fluoride existing in in the
child’s water supply. This required collecting water and having the
fluoride content assessed by a laboratory.
• Compliance with children taking the tablets was also a significant
problem.
• Compliance has been demonstrated to be improved when combined
with children’s vitamins. Individual sodium fluoride tablets in varying
concentrations are still available by prescription, as are children’s
vitamins with fluoride. Typical concentrations are 0.25 – 1.0 mg.
• A number of countries internationally add fluoride to their salt rather
than to their water. Has been demonstrated to be effective.
Mechanism of Fluoride Action
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Early work on water fluoridation led to the
assumption that it was the incorporation
of the fluoride ion into the hydroxyapatite
crystalline structure during tooth
development that imparted caries
resistance.
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More recent work indicates that this is
probably not the case. Rather, caries
reduction is more related to the posteruptive topical effect of the fluoride
rather than the pre-eruptive systemic
developmental effect on tooth
development.
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Fluoride in saliva (and in plaque) inhibits
the demineralization of sound enamel
and enhances the remineralization of
demineralized enamel. The fluoride is
taken up by the demineralized enamel
along with calcium and phosphate to
establish an improved enamel crystalline
structure.
Topical Fluoride Therapeutics
• Interestingly, the early studies of water fluoridation
found that the anterior teeth had a greater
reduction in caries than did the posterior teeth.
This led to speculation that there was a topical
effect, as the water being drunk came into more
intimate contact with the anterior teeth versus the
posterior.
• Thus the therapeutic approach to using fluorides
topically emerged, and with that fluoride
dentifrices, professional applied high potency
topical fluorides, and fluoride mouth rinses.
Professionally Applied
High Potency Topical Fluorides
• High potency topical fluorides for professional
application are compounded differently, with
different strengths, and available in a variety
of vehicles for application:
– 2% Sodium Fluoride (0.9% fluoride; 9,000 ppm)
in gel or foam.
– Acidulated Phosphate Fluoride (1.23%; 12,300
ppm) in gel or foam.
– 5% Sodium Fluoride as a varnish (2.26% fluoride;
22,600 ppm)
• Only fluoride varnish is recommended to be
used for children under 6 years.
Acidulated Phosphate Topical
Fluorides
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Early studies reported that fluoride
uptake by enamel increased in an
acidic environment.
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APF fluorides are formulated to be
highly acidic with a pH of 3.0.
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Teeth should be dry prior to
application
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If liquid or gel used, it must be
flossed between contacts.
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If foam used in a tray, it is
assumed that the pressure of the
tray will force the fluoride into the
contact areas. (Questionable)
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Post-treatment instructions include
not eating or drinking anything for
30 minutes.
Fluoride Varnish
Cavity shield comes in unit does packages; .25 ml for the primary dentition,
and .40 ml for the mixed and permanent dentition.
Fluoride Varnish
• Fluoride varnish was developed and began to be used in Europe in the
1970s.
• It was introduced in the United States in the 1990s and is becoming the
most popular high potency topical fluoride used by dentists. It is only
approved for desensitizing exposure root surfaces; therefore is used “off
label.”
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It has the advantages of: high concentration of fluoride in small volume
of material; held in close contact with the teeth for extended period of
time; ease of application; and non-offensive taste.
• The only brand of varnish that has been studied for efficacy is Duraphat
by Colgate. Other brands are presumed to be effective as of similar
content. Duraphat has the disadvantage of leaving the teeth with a
yellowish-brown stain for a short time following application. Competitive
brands are clear or white and do not have this disadvantage, thus
enhancing their market popularity. (Cavity Shield and Vanish)
• Post-treatment instructions for fluoride varnish include not brushing the
teeth until the next day.
Clinical Considerations in High
Potency Topical Fluorides
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Topical fluorides must be used regularly and repeatedly to be effective. If so,
they can be expected to reduce dental caries in children at risk for dental
caries by approximately 40%.
Teeth must be dry on application.
Topical fluorides are not cost effective in children at low risk for dental
caries, therefore should be used on children at moderate or high risk for
dental caries, specifically, not in areas of water fluoridation.
Topical fluorides have relatively little preventive impact on pit and fissure
lesions; reason sealants necessary. Primary effect is on smooth surfaces.
Caries on smooth surfaces is most frequently on the proximal surfaces.
Therefore, the fluoride must be flossed into the inter-proximals of teeth to
gain the caries preventive effect of topical fluorides.
While varnishes adhere to the teeth for an extended period, gels and foams
do not, and therefore must be applied and remain on dry teeth for a full four
minutes. (One company markets a one minute foam—this has never been
demonstrated to be effective.)
There is NO evidence that the use of a fluoride prophylaxis paste offers any
caries resistance.
Fluoride Toothpaste
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Brushing with fluoride toothpaste increases
fluoride concentration in saliva by 1001,000 fold; returning to baseline in 1-2
hours.
Children older than six years of age can
retain more fluoride in their saliva by not
rinsing after brushing. (Younger children
should not do this as will swallow the
toothpaste with potential for fluorosis.)
Concentration of fluoride in fluoride
toothpaste is 1,000-1,500 ppm
Regular used of fluoride toothpaste
reduces caries experience by 15-30%.
Fluoride toothpaste accounts for 90% of
toothpaste market in the United States.
Community water fluoridation and
brushing with a fluoride toothpaste are
the two most cost-benefit effective uses
of fluoride in preventing dental caries.
Fluoride Toothpaste
• Young children, less than 6
years old, are at risk for
fluorosis as a result of a
tendency to swallow
toothpaste.
• Infants and toddlers (age 3)
should only have a “smear” of
toothpaste used.
• Parents are advised to only
place a “pea-sized” amount of
toothpaste on the child’s
toothbrush.
• Prevalence of fluorosis in the
U.S, is 22-23% of children.
Prevident Dentrifice
• Prevident is a high concentration fluoride dentrifice
(1.1% sodium fluoride), by Colgate.
• Available by prescription only.
• Indicated for children over age 6 who have are at
high risk for dental caries.
Fluoride Mouthrinses
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Most common ingredient is sodium
fluoride; typically at 0.05%
concentration.
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Again, due to the potential for
fluorosis, not recommended for
children under age 6.
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Average caries reduction with daily
use in non-fluoridated community
approximately 30%.
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Indicated for children with moderate
to high caries experience, especially
if they live in a non-fluoridated
community.
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Brands include: ACT, Duraphat
Rinse FluoriGard, and Fluorinse