AMRITA SCHOOL OF DENTISTRY

1. Current Concepts of Fluoride Use
Seminar1
7

2. CONTENTS 2
• Introduction
• History of Flouride Use
• Mechanism of action of fluoride
• Ways of administration of fluorides
• Systemic administration
• Topical Administration
• New advancements
• Conclusion
• References

3. 3
INTRODUCTION
Safe, effective,
cost-effective,
feasible
Toothpaste,
Water
Fluoridation
and
Community-
based
F
L
O
U
R
I
D
E

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• Fluorides have been extensively employed to control dental caries.
1900s
• H. Trendley Dean proposed the optimum level of exposure to fluoride to provide the maximum protection
against caries, with minimum dental fluorosis.
1942
• Fluoride's systemic action was found to be inadequate to prevent decay, as the amount absorbed wasn't
sufficient. However, low fluoride levels in oral fluids inhibited demineralization and enhanced
remineralization. This discovery led to the concept of fluoride's "topical" action, where it is constantly present
at low concentrations in the oral environment.
1980s
• The current concept regarding the mechanisms of action of fluorides against caries was questioned, and the
possibility to obtain caries protection even with low levels of fluoride intake was recognized. Thus, controlling
the fluoride intake rapidly came into focus in different areas of the world.
1980s-1990s
HISTORY

5. MECHANISM OF ACTION OF FLUORIDE
• Remineralization of Enamel
• Inhibition of Demineralization
• Antimicrobial Effects
• Enhancing the Formation of Fluorapatite
5

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Pre-eruptive Flouride
• Development and
maintenance of strong,
healthy enamel
• Systemic fluoride
• Incorporated into the
developing enamel as the
tooth forms within the
jawbone.
• Reducing the risk of
caries.
• Eg: community water
fluoridation
Post-eruptive Fluoride
• Development and
maintenance of strong,
healthy enamel
• Topical fluoride exposure
• On exposure to fluoride-
containing products, in
outer surfaces of the
enamel, which helps to
strengthen and protect it
from acid attack.
• Reducing the risk of
caries.
• Eg: topical fluoridation

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ETIOLOGY AND RISK FACTORS
• Dental fluorosis, is caused by
excessive fluoride intake during tooth
development, with the most vulnerable
period being the first 6 to 8 years of
life, and the most critical period for
permanent maxillary central incisors
being the first 3 years.
• To minimize the risk of dental fluorosis,
fluoride intake in children should be
monitored during the first three years
of life.
• However, for the control of dental
caries, fluoride exposure should be
maintained throughout life.

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Genetic Factors
Studies :
• Genetic factors may predispose individuals to dental fluorosis, inbred mice strains have been
found to have different susceptibilities to dental fluorosis due to differences in fluoride
metabolism.
• Histological examination of maturing enamel showed that amelogenins accumulated in the
enamel of susceptible mice exposed to fluoride, but not in the resistant mice.

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Biomarkers of Exposure to Fluoride
• Biomarkers of fluoride exposure are essential for identifying and monitoring deficient or
excessive intakes.
• These biomarkers are classified as contemporary (assessing present or recent exposure) or recent
and historical (assessing chronic or subchronic exposure).
• The most useful contemporary biomarker is daily urinary fluoride excretion, while fluoride
concentrations in parotid and submandibular saliva are proposed to be related to plasma fluoride
concentrations.
• Fingernail fluoride concentrations in ages 2 to 7 have been validated as predictors for dental
fluorosis.

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WAYS OF ADMINISTRATION OF FLUORIDES
Systemic Administration
Topical Administration

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Fluoride can improve the crystallinity of enamel by increasing crystal size and reducing strain in the crystal lattice.
Flouride can fill voids in hydroxyapatite crystals, which increases stability and chemical reactivity by forming stronger
hydrogen bonds. The decreased solubility of fluoridated enamel can be attributed to the presence of fluorapatite, which is
less soluble than hydroxyapatite.
However, the amount of fluoride in surface enamel from individuals living in a fluoridated area is only a fraction of the
theoretical amount of fluoride in fluorapatite, and the actual difference in the amount dissolving is usually negligible.
Studies have shown that individuals living in high fluoride areas have smaller cusp height and less convexity in their teeth,
indicating an influence of fluoride on tooth morphology.
Systemic Effect of Fluoride
SYSTEMIC ADMINISTRATION

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Updated recommendations for systemic fluoride
use
• The recommended fluoride concentration in
public water supplies is now 0.7 ppm.
• This recommended level updates and replaces
the previously recommended range of 0.7-1.2
milligrams of fluoride ion per litre (i.e., parts
per million fluorides [ppm F]).
(American Academy of Pediatric Dentistry (AAPD), the
ADA and the American Academy of Pediatrics)
Systemic Administration
Water
fluoridation
Community
Water
fluoridation
School Water
fluoridation
Other
fluoridations
Salt
fluoridation
Milk
fluoridation
Fluoride
Tablet

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Topical fluoride can have low or high concentrations and can be either frequently or sporadically exposed to have
an effect on oral bacteria.
Fluoride inhibits enzymes such as enolase and glucose transport, leading to a reduction in acid production. It also
suppresses bacterial growth and has antibacterial properties.
Fluoride can be incorporated into tooth enamel pre-eruptively or post-eruptively, resulting in the formation of
fluoride-rich crystals that are less soluble in acid.
The specific plaque hypothesis suggests that the elimination or reduction of S. mutans, a specific pathogen,
through topical fluoride treatment can lead to lasting cariostatic effects.
Topical Effect of Fluoride
TOPICAL ADMINISTRATION

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5% sodium fluoride varnish (22,600 ppm)
Neutral sodium fluoride (9,050 ppm) and APF
(12,300 ppm) foams/gels
2% sodium fluoride rinses (9,050 ppm) and dual
rinses (3,300 ppm)
Professionally Applied Topical Fluorides
Current recommendations for professionally-applied topical fluorides
For low-risk patients, a fluoride dentifrice may offer sufficient protection, although clinical judgment
should be used to determine whether an in-office topical fluoride is necessary.
Topical application
Dentifrice
Fluoride
rinses
Pastes
Gels &
Solution
NaF
Applicatio
n
SnF
Applicatio
n
APF
Applicatio
n
Source: Current Concepts in Fluoride Therapy - ACT Professional

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18. WHO Global School-based Student Health Survey:
The survey on 75 low- and middle-income countries revealed that :
• 35–94% (12-15-year-olds)- brush their teeth 1 - 3 times a day
• 2% - 38% - not brushing their teeth at all
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Fluoride dentifrices
Current recommendations: 1,000 – 1,100 ppm dentifrices
• Children age 2 until age 6: Use of a pea-sized amount twice daily, brushing under supervision
(rinsing and expectorating after brushing)
• Age 6 onward: Twice-daily brushing with toothpaste; may require supervision until age 10 or
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Over-the-counter (OTC) Topical Fluorides

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Source: The Global Status Report on Oral Health 2022 (WHO)

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1. For children younger than 3 years, caregivers should begin brushing children’s teeth as soon as they
begin to come into the mouth by using fluoride toothpaste in an amount no more than a smear or
the size of a grain of rice (Figure).
2. For children 3 to 6 years of age, caregivers should dispense no more than a pea-sized amount
(Figure) of fluoride toothpaste.
3. It is especially critical that dentists provide counseling to caregivers that involves the use of oral
description, visual aids and actual demonstration to help ensure that the appropriate amount of
toothpaste is used.

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Fluoride rinses
0.05% sodium fluoride rinse
0.044% acidulated phosphate fluoride rinse
Current directions for OTC fluoride rinses
• Fluoride rinses are not recommended for the under-6 age group, due to the risk of swallowing
• 0.05% sodium fluoride and 0.044% acidulated phosphate fluoride are recommended for daily use
• 0.02 – 0.21% fluoride rinses must be used twice daily
• Plaque and salivary fluoride levels are higher with the use of higher-ppm fluoride rinses
• Nighttime use results in prolonged fluoride retention in whole saliva compared to daytime use
Source: Current Concepts in Fluoride Therapy - ACT Professional

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Prescription Home-use Pastes, Gels and Rinses
1.1% sodium fluoride (5,000 ppm)
pastes/gels
0.2% sodium fluoride rinse (920 ppm)
0.63% stannous fluoride rinse
Current directions for 1.1% sodium fluoride
• Not recommended for children under age 6
• Recommended for twice-daily use in patients at high risk for caries
• Patients should expectorate after use, not rinse, to maintain a higher level of bioavailable fluoride
Source: Current Concepts in Fluoride Therapy - ACT Professional

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Fluoride Mouthwash
In-office Fluoride Treatment
Fluoride-releasing Dental Materials
Other topical fluoride treatments

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Young children
• Fluoride varnish every 6
months for moderate risk,
and 2 to 4 times per year for
high-risk patients
• Age-appropriate OTC fluoride
dentifrice use
• Topical fluoride rinses are
NOT recommended due to
the risk of swallowing and
fluorosis.
Orthodontic patients
• Fluoride varnish or gel every
6 months for moderate risk,
and 2 to 4 times per year for
high-risk patients.
• Home-use topical fluoride:
• For patients with no
cavitated lesions, twice-
daily OTC dentifrice use and
daily use of 0.05% sodium
fluoride rinse
• For patients with cavitated
lesions, 1.1% prescription-
strength sodium fluoride
paste/gel
• Daily use of 0.05% fluoride
rinse inhibits enamel lesions
adjacent to FOA.
Xerostomic patients
• In-office fluoride varnish or
fluoride gel 2 to 4 times per
year
• Home-use topical fluoride:
• 5,000 ppm fluoride
paste/gel once- or twice-
daily (if once daily, fluoride
dentifrice should be used
the second time daily) AND
daily use of a 0.05% sodium
fluoride rinse as well as
when the mouth feels dry
or after eating/drinking.
Recommendations on Topical fluoride therapy:

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• Research shows that fluoride uptake in enamel is time-dependent, and the full four minutes of
application with the gel tray method provides the best topical benefit.
• The ADA recommends professional topical fluoride applications based on caries risk factors, with
sodium fluoride varnish or APF gel being applied every 3-6 months for children at risk for
caries.
• While sodium fluoride varnish has a higher fluoride concentration, fluoride's efficacy is
enhanced with an acidic environment, making APF gel effective as well.
• Dental professionals should determine if professional fluoride applications are appropriate for all
patients based on their caries risk factors.
One-minute vs. Four-minute fluoride applications
Source: https://www.dentalcare.com/en-us/ce-courses/ce334/one-minute-vs-four-minute-fluoride-application

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The panel recommends the following for people at risk of
developing dental caries: 2.26 % fluoride varnish or 1.23
% fluoride (acidulated phosphate fluoride) gel, or a
prescription-strength, home-use 0.05 % fluoride gel or
paste or 0.09 % fluoride mouth rinse for patients 6
years or older. Only 2.26 % fluoride varnish is
recommended for children younger than 6 years. The
strengths of the recommendations for the recommended
products varied from ”in favor“ to ”expert opinion for.“
These recommendations are an update of the 2006 ADA recommendations.

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1. Fluoride use for the prevention and control of caries is both safe and highly effective in
reducing dental caries prevalence.
2. Fluoride dietary supplements are effective in reducing dental caries and should be considered
for children at caries risk who drink fluoride-deficient (less than 0.6 ppm) water.
3. Professionally applied topical fluoride treatments as 5% NaFV or 1.23 % F gel preparations
are efficacious in reducing caries in children at caries risk.
Current recommendations of Fluoride therapy (Evidence- based)
Source: American Academy of Pediatric Dentistry. Fluoride therapy. The Reference Manual of Pediatric Dentistry. Chicago, Ill.: American Academy of
Pediatric Dentistry; 2022:317-20.

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4. Fluoridated toothpaste is effective in reducing dental caries in children. Using no more than
a smear or rice-size amount of fluoridated toothpaste for children less than three years of age
may decrease risk of fluorosis. Using no more than a pea-size amount of fluoridated
toothpaste is appropriate for children aged three to six.
5. Prescription-strength home-use 0.5 % fluoride gels and pastes and prescription-strength
home-use 0.09 % fluoride mouthrinse also are effective in reducing dental caries.
6. Recommend the use of 38 % silver diamine fluoride for the arrest of cavitated caries
lesions in primary teeth as part of a comprehensive caries management program
Source: American Academy of Pediatric Dentistry. Fluoride therapy. The Reference Manual of Pediatric Dentistry. Chicago, Ill.: American Academy of
Pediatric Dentistry; 2022:317-20.

29. New Advancements
Silver Diamine Fluoride (SDF)
Fluoride Varnish
Nano-Fluoride
Fluoride-releasing dental implants
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Source: The Global Status Report on Oral Health 2022 (WHO)

30. SILVER DIAMINE FLUORIDE (SDF) 30
• Silver diamine fluoride (SDF) is a colorless liquid used to treat tooth
sensitivity and is a Class II medical device cleared by the FDA.
• SDF can be used for caries control and management, although it is not
specifically FDA-labeled for this use (i.e., "off-label use").
• SDF may be a preferred option for caries arrest in deciduous teeth, older
individuals, and when access to conventional restorative techniques is
not available or advanced sedation techniques are not desired.

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SDF for Treatment of Dentin Sensitivity
• SDF has been cleared by the FDA as a dentin
desensitizing agent.
• When applied to areas with sensitive dentin
surfaces, a layer of silver and dentin organic
matrix protein conjugates forms.
• This squamous layer formed on the exposed
dentin surface partially closes the exposed
dentin tubules.

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SDF effectively
reduces the growth
of cariogenic
bacteria, such as
Streptococcus
mutans, on dentine
surfaces. SDF results
in significantly
lower colony-
forming unit counts
of mono- and dual-
species biofilms,
with a higher dead-
to-live ratio of
bacteria. SDF has
also been found to
inhibit the
adherence of S.
mutans to tooth
surfaces.
SDF has shown to
promote
remineralization of
demineralized tooth
surfaces. It
increases surface
microhardness and
reduces the depth
of carious lesions,
slowing down their
progression.
SDF promotes
calcium absorption
and inhibits calcium
dissolution from
enamel. It also
results in the
formation of silver
chloride, metallic
silver, calcium
fluoride, and silver
phosphate.
Elemental analysis
shows that
demineralized
dentine treated with
SDF has higher
calcium and
phosphorus
content, with less
mineral loss.
SDF has also been
found to inhibit the
enzymatic
degradation of
collagen by matrix
metalloproteinases
and cysteine
cathepsins. Overall,
SDF has shown
promise as an
effective treatment
for caries, with
antibacterial and
remineralization
properties.
Actions of SDF
(cariogenic bacteria, mineral content of enamel and dentine, and organic content of dentine)

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• AAPD made a conditional recommendation for SDF use in managing caries in children and
adolescents.
• Application of 38% SDF prevents root caries in adults with higher success rates than placebo
treatment.
• Disadvantages of SDF include potential pulpal and oral soft tissue irritation and dental staining.
• Further restoration may be needed after SDF treatment to recover the form and function of a cavitated
tooth.
• Limited evidence on the adhesive performance of traditional restorative options following caries arrest
with SDF.
• Once-yearly SDF application is more effective in preventing caries than more frequent
application of fluoride varnish, and SDF is only more effective in preventing caries if continuously
applied when compared to occlusal sealants.
Uses of SDF

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Systematic reviews consistently supported SDF’s
effectiveness for arresting coronal caries in the
primary dentition and arresting and preventing
root caries in older adults for all comparators.
There is insufficient evidence to draw conclusions
on SDF for prevention in primary teeth and
prevention and arrest in permanent teeth in
children. No serious adverse events were reported.

35. Fluoride varnish is a thin, protective coating that is applied to the teeth to prevent tooth decay in
both primary and permanent teeth. It is a quick and easy procedure that can be performed by a
dentist or dental hygienist.
FLUORIDE VARNISH 35

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Fluoride varnish painted onto
enamel or cementum forms a
clear or slightly yellowish film
Slow release of fluoride ion to
the tooth surface
Fluoride in liquid phase
around apatite crystallites
blocks crystalline dissolution
and reduces demineralization
Increased fluoride ion activity
enhances mineral deposition
and promotes remineralisation
in sound or carious enamel
Greater fluoride
concentrations attainable with
varnishes produce deposits of
calcium fluoride, depositing
fluoride in porosities and
microchannels in enamel
Fluoride reservoirs gradually
release fluoride into dental
plaque, saliva, or apatite
structure of the tooth when
the pH drops
Mechanism of Action

37. Amorphous Calcium Phosphate (ACP):
• ACP promotes remineralization of enamel, balances saliva pH, and
reduces sensitivity.
• Combined with fluoride, ACP increases calcium and phosphate levels in
tooth structure.
• ACP benefits orthodontic, high-risk caries, and acid erosion patients.
• ACP with fluoride toothpaste decreases bacteria and increases
mineralization.
• Custom mouthguards extend application time.
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39. Nano-fluoride is a form of fluoride that has been
broken down into very small particles. These small
particles can penetrate deeper into the tooth enamel,
making them more effective in preventing tooth decay.
Recent studies have shown that nano-fluoride is more
effective in preventing tooth decay than traditional
fluoride treatments.
NANO-FLUORIDE
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41. Dental implants are used to replace missing
teeth. Recent advancements in implant
technology have resulted in the development
of fluoride-releasing dental implants. These
implants release fluoride into the
surrounding tissues, which can help to
prevent tooth decay and implant failure.
FLUORIDE RELEASING DENTAL IMPLANTS
41

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43. • Regular use of fluoride-containing dentifrice is effective in preventing
caries on an individual and community level as it combines oral
hygiene with fluoride supplementation.
• Fluoride-containing mouth rinses, varnishes, and gels can provide
additional protection for people with moderate to high caries
activity.
• Fluoride tablets or lozenges can also be used as a topical fluoride
application for those who cannot or will not use a fluoridated
dentifrice.
• In areas with fluoridated drinking water, the use of fluoride tablets is
not recommended due to potential toxicity concerns, and children
using fluoride dentifrice in these areas should be able to spit out
adequately after brushing.
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Summary

44. 1. Rosenblatt A, Stamford TC, Niederman R. Silver Diamine Fluoride: A Caries "Silver-Fluoride Bullet". Journal of
Dental Research. 2009;88(2):116-125. doi:10.1177/0022034508329406
2. American Dental Association. Fluoride Varnish. https://www.ada.org/en/member-center/oral-health-
topics/fluoride-varnish
3. Singhal A, Pal N, Kulkarni DD, Dutt K, Malik A, Singh R. Nano-fluoride in preventive dentistry: A new paradigm
in dental caries management. Journal of Clinical and Diagnostic Research. 2017;11(8):ZE21-ZE25.
doi:10.7860/JCDR/2017/28094.10352
4. Subramani K, Jung RE, Molenberg A, Hammerle CHF. Bioactive ceramics for periodontal regeneration: A
review of material properties and clinical outcomes. International Journal of Periodontics and Restorative
Dentistry. 2017;37(5):e261-e269. doi:10.11607/prd.3099
5. https://www.dentalcare.com/en-us/ce-courses/ce334/current-theories-regarding-fluoride-use
44
References

45. 45
6. FDI Commission. Mouthrinses and dental caries. Int Dent J. 2002;52(5):337–45.
7. Cooper L, Komarov GN, Shaw KE, Pretty IA, Ellwood RP, Birkhed D, Smith PW, Flannigan NL, Higham SM. Effect
of post-brushing mouthwash solutions on salivary fluoride retention - study 2. J Clin Dent. 2012;23(3):92-6.
8. 49. Mystikos C, Yoshino T, Ramberg P, Birkhed D. Effect of post-brushing mouthrinse solutions on salivary
fluoride retention. Swed Dent J. 2011;35(1):17-24.
9. Baysan A et al. Reversal of primary root caries using dentifrices containing 1,000 and 5,000 ppm fluoride.
Caries Res. 2001;35:41–6.
10. DePaola P., ed. Cariology for the nineties. Caries in our aging population: What are we learning? Ed. W.H.
Bowen and L.W. Tabak. 1993;26-35.
11. Leverett DH, Sveen OB, Jensen OE. Weekly rinsing with a fluoride mouthrinse in an unfluoridated community:
results after seven years. J Public Health Dent. 1985 Spring;45(2):95 – 100.
12. Radike AW, Gish CW, Peterson JK, King JD, Segreto VA. Clinical evaluation of stannous fluoride as an
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