Public Health Dentistry

1. BY-
MALIK ABDUL
FINAL YR

2. 
 Member of the halogen family with relative atomic
weight 19
 Atomic number – 9
 Fluorine derived from Latin term ‘fluore’ meaning,
“to flow”
 Occurs in combined form such as Fluorspar[fluorite
CaF2], Fluorapatite[Ca10F2(PO4)6], Cryolite[NaAlF6]
The element Fluorine

3.  Dr. Fredrick McKay (Colorado Springs, Colorado, USA) –
1901 saw the stains on the teeth of his pts. The local
inhabitants called it the ‘Colorado stain’.
 He called the stain “mottled enamel”.
 First systemic endeavour to investigate the lesion was
made by the Colorado springs dental society in 1902
 He approached one of the America’s foremost authorities
on dental enamel, Dr. Greene Vardiman Black.
 Black asked him to send the mottled teeth for
examination after that he agreed to attend the Colorado
state dental association meeting in 1909, and promised to
spend some weeks in Colorado springs before the
meeting.
HISTORY

4. 
 In 1931 U.S. govt appointed Dr. Trendly H Dean to
continue the work of Mckay.
 Dean conducted survey in 22 cities in USA.

5. 
 Canned fish products – Salmon & Sardin – 20-
40mg/kg
 Fish protein concentrates – 370mg/kg
 Jowar, banana, potatoes
 Rock salt (40-200ppm)
 Dried tea leaves (100-400ppm)
Sources of fluoride

6. 
 Increase enamel resistance (or) reduction in enamel
solubility
 Increased rate of posteruptive maturation
 Remineralization of incipient lesions
 Interference with plaque microorganisms
 Modification with tooth morphology
Mechanism of action of
fluorides

7. 
 Fluoride inhibits demineralization in several ways,
 By reducing bacterial acid production
 By reducing the equilibrium solubility of apatite
 By the fluoridation of apatite crystal surfaces
reducing the dissolution rate whether or not there is
reduced solubilty of the bulk material
Increased enamel resistance/Reduction
in enamel solubility

8. 
 Importance of fluoride in maturation process lies in
its ability to increase the rate of mineralization of
hypomineralized areas
 Posteruptive maturation involves deposition of
minerals into hypomineralized areas
Increased rate posteruptive
maturation

9. 
 Fluoride plays critical role in the reducing of dental
caries by enhancing remineralization.
 Remineralization, the deposition of minerals into
previously damaged areas of the tooth is a process
that results in enamel solubility
Remineralization of incipient
lesions

10. 
 Fluoride has been known to inhibit bacterial
enzymatic processes involved in carbohydrate
metabolism
 In high conc., fluoride is bactericidal. Helps reduce
plaque
 In lower conc., fluoride is bacteriostatic. Helps
control the growth of bacteria without destroying
them.
Interferance with
microorganisms

11. 
 If fluoride is ingested during the tooth development,
there is some evidence to suggest the fromation of a
more caries resistant tooth slightly smaller with
shallow fissures.
Modification in tooth
morphology

12. FLUORIDE DELIVERY METHODS
Fluoride can be delivered as…
(A) Topical Fluorides
(B) Systemic Fluorides

13. TOPICAL FLUORIDES SYSTEMIC FLUORIDES
 These are placed directly
on the teeth
 Some preparations
provide high or low
concentrations of fluoride
over a short period of
time
 These circulate through
the blood stream and are
incorporated into
developing teeth
 They provide a low
concentration of fluoride
over a long period of
time

14. 
TOPICAL FLUORIDES
By the definition the term “topically applied fluorides”
is used to describe those delivery systems which
provide fluoride for a local chemical reaction to
exposed surfaces of the erupted dentition.

15. INDICATIONS
 Caries active individuals
 Children shortly after period of tooth eruption
 Those who take medication that decrease salivary
flow or have received radiation to head and neck
 After periodontal surgery when roots of teeth have
been exposed
 Patients with fixed or removable prosthesis and after
placement or replacement of restorations
 Patients with an eating disorder or who are
undergoing a change in lifestyle which may affect
eating or oral hygiene habits conductive to good oral
health
 Mentally and physically challenged individuals

16. TOPICAL FLUORIDE PRODUCTS ARE
DIVIDED INTO 2 CATEGORIES
(A) Professionally applied
 Introduced by Bibby in 1942
 Dispensed by dental professionals in the dental office
and usually involve the use of high fluoride
concentration products ranging from 5000-19000 ppm
which is equivalent to 5-9 mg F/ml
(B) Self applied
 Include fluoride dentifrices, mouth rinses & gels
 Are low fluoride concentration products ranging from
200-1000ppm or 0.2-1 mgF/ml.

17. RATIONALE FOR USING TOPICAL
FLUORIDE AGENTS
 To speed up the rate and increase the
concentration of fluoride acquisition above
the level which occurs naturally
 The initial caries lesion characterized by a
white spot is porous and accumulates
fluoride at a much higher concentration than
adjacent sound enamel hence periodic
application of fluoride would enable
vulnerable enamel sites that are partially
demineralized to accumulate fluoride

18. PROFESSIONALLY APPLIED
FLUORIDES
FLUORIDE VEHICLES
 AQUEOUS SOLUTIONS AND GELS
 Gel adheres to the tooth surface for a considerable
amount of time and eliminates the continuous wetting
of enamel surfaces when solutions are used
 2 or 4 quadrants can be treated simultaneously when
trays are used for gel application which results in
substantial saving of time
 Thyxotrophic solutions are not gels but have high
viscosity under storage conditions and become fluid
under high stress
 Thyxotrophic solutions are more stable at lower pH
and do not run off the tray as readily as conventional
gels

19. GELS

20. FLUORIDATED PROPHYLACTIC PASTES
 If prophylaxis pastes
containing fluoride are
used, the lost fluoride is
replenished & there is a
significant gain in the
concentration of
fluoride.

21. FOAM
 Developed to minimize the risk of fluoride over
dosage as well as to maintain the efficacy of topical
fluoride treatment.
 ADVANTAGES:
 Its lighter than a conventional gel & therefore only a
small amount of agent is needed for topical
application
 The surfactant has cleansing action by lowering
surface tension, this facilitates the penetration of
material into interproximal surfaces.
 It doesn’t require suctioning so it offers advantages for
home use

22. FOAM

23. FLUORIDE VARNISH
 It was first developed by Schimdt in Europe in 1964
 Increasing the time of contact between enamel surface
& topical fluoride agents favors the deposition of
fluorapatite & fluorhydroxyapatite.
Technique:
 After prophylaxis teeth are dried but not isolated with
cotton rolls since varnish sticks to cotton
 Total of 0.3-0.5 ml of varnish is required to cover full
dentition
 Application is done first done on lower arch then
upper, using single tufted small brush, starting with
proximal surfaces
 Patient is asked to sit with mouth open for 4 min to let
Duraphat set on teeth

24. FLUORIDE
VARNISH

25.  Patient is asked to not rinse or drink anything for one hour
and advised liquid diet till next morning
 DURAPHAT:
It is a first fluoride varnish developed in germany, viscous
yellow material, containing 22,600 ppm fluoride as sodium
fluoride in a neutral colophonium base.
 FLUORPROTECTOR:
It is a clear polyurethane based product containing 7000
ppm fluoride from difluorosilane.
It is dispensed in 1ml ampoules each ampoule containing
6.21mg of fluoride.
 CAREX:
It has low fluoride concentration than duraphat & has
equal efficacy to that of duraphat as caries preventive
agent

26. TOPICAL FLUORIDES USED IN PREVENTIVE
DENTISTRY:
 SODIUM FLUORIDE
 STANNOUS FLUORIDE
 ACIDULATED PHOSPHATE FLUORIDE
 AMINE FLUORIDE
1) NEUTRAL SODIUM FLUORIDE (NaF)
 Fluoride concentration - 9200ppm
 A minimum of four applications with a 2% NaF
solution gives a caries reduction of about 30%
 METHOD OF PREPARATION
 It is prepared by dissolving 20 gms of NaF powder in
1L of distilled water in a plastic bottle

27.  TECHNIQUE - KNUTSON’S TECHNIQUE
 At the initial appointment teeth are cleaned with pumice slurry &
then isolated with cotton rolls & dried with compressed air.
 Using cotton-tipped applicator sticks ,the 2% NaF is painted on air
dried teeth so that all tooth surfaces are visibly wet. The solution is
allowed to dry for 3-4 min.
 This procedure is repeated for each of the isolated segments until all
the teeth are treated.
 A 2nd, 3rd and 4th fluoride application, each not preceded by a
prophylaxis, is scheduled at intervals of approximately one week;
 The four-visit procedure is recommended for ages 3, 7, 11 and 13
years, coinciding with the eruption of different groups of primary
and permanent teeth.

28.  MECHANISM OF ACTION :
 When NaF is applied on tooth surface it reacts with
hydroxyapatite crystals in enamel to form Calcium fluoride
(CaF2) which is the dominant product of the reaction
 As thick layer of CaF2 forms, it interferes with further diffusion
of fluoride from the topical fluoride solution to react with
hydroxyapatite and blocks further entry of fluoride ions. This
sudden stop of the entry of fluoride is termed as ‘chocking off
effect’
 CaF2 acts as a reservoir and fluoride slowly leeches out of it
 The CaF2 formed reacts with hydroxyapatite fluoridated
hydroxyapatite increases the concentration of fluoride on
enamel surface prevents caries

29.  ADVANTAGES :
 It is relatively stable when kept in a plastic container;
 The taste is well accepted by patients;
 The solution is non-irritating to the gingiva;
 It does not cause discoloration of tooth structure;
 The series of treatments must be repeated only 4 times
in the general age range of 3 to 13, rather than at
annual or semiannual intervals.
 DISADVANTAGES:
 The major disadvantage of the use of sodium fluoride
is that the patient must make 4 visits to the dentist
within a relatively short period of time.

30. 2) STANNOUS FLUORIDE (SnF2)
 Fluoride concentration-19500ppm
 Stannous fluoride has been used at 8% and 10%
concentrations
 METHOD OF PREPARATION:
 Solutions of stannous fluoride are not stable. Soon after
mixing they become cloudy due to the formation of tin
hydroxide.
 A fresh solution of stannous fluoride be prepared for each
patient.
 To prepare 8% stannous fluoride solution, the content of
one capsule which is 0.8 grams (‘0’ No. of gelation capsule)
is dissolved in 10 ml of distilled water in a plastic container.

31.  TECHNIQUE - MUHLER’S TECHNIQUE
 Each tooth surface is cleaned with pumice or other
dental cleaning agent for 5 to 10 seconds;
 Unwaxed dental floss is passed between the
interproximal areas;
 Teeth are isolated and dried with air;
 Stannous fluoride is applied using the paint-on
technique and the solution is kept for 4 minutes.
Repeat applications are made every 6 months or more
frequently if the patient is susceptible to caries.

32.  MECHANISM OF ACTION:
 When SnF2 is applied in low concentration
tinhydroxyapatite, which gets dissolved in oral tissues
 At very high concentration Ca trifluorostannate forms
along with tin tri-fluorophosphate
 Tin trifluorophosphate is responsible for making the
tooth structure more stable and less susceptible to
decay
 CaF2 is the end product both at low and high
concentration which reacts with hydroxyapatite and a
small fraction of fluorhydroxyapatite also gets formed

33.  ADVANTAGES :
 Using an 8% stannous fluoride solution at 6 to 12 months
intervals conforms to the practicing dentist’s usual patient –
recall system;
 Administrative difficulties are avoided.
 DISADVANTAGES :
 In aqueous solution the material is not stable;
 8% solution is quite astringent and disagreeable in taste, its
application is unpleasant;
 The solution occasionally causes a reversible tissue
irritation manifested by gingival blanching;
 Causes pigmentation of teeth which has a characteristic
light brown colour

34. 3) ACIDULATED PHOSPHATE FLUORIDE (APF)
 Fluoride concentration-12300 ppm
 METHOD OF PREPARATION
An aqueous solution is acidulated phosphate fluoride
is prepared by dissolving 20 grams of sodium fluoride
in 1 liter of 0.1 M phosphoric acid and to this is added
50% hydrofluoric acid to adjust the pH at 3.0 and
fluoride ion concentration at 1.23%. It is also called as
Brudevold’s solution
For the preparation of acidulated phosphate fluoride
gel, a gelling agent methylcellulose or hydroxyethyl
cellulose is added to the solution.

35.  TECHNIQUE
 APF is recommended for application at 6 or 12 months
interval
 Oral prophylaxis is done
 Teeth to be treated are completely isolated and
thoroughly dried with air
 Application of gel is done using trays; disposable
foam lined trays are preferred
 It is reapplied every 15-30sec so as to keep the teeth
moist with the fluoride solution throughout the four
min period
 The patient is instructed to eat, drink or rinse his
mouth for atleast 30 min

36. FLUORIDE
TRAYS

37.  MECHANISM OF ACTION
 When APF is applied to teeth it initially leads to
dehydration and shrinkage in the vol of hydroxyapatite
crystals which on hydrolysis forms an intermediate
product called Dicalcium phosphate dihydrate(DCPD)
 DCPD is highly reactive and starts forming immediately
after APF is applied
 Fluoride penetrates into the crystals more deeply through
the openings produced by shrinkage and forms fluorapatite
 For the conversion of whole DCPD formed into
fluorapatite, a deeper penetration and continuous supply of
fluoride is required. Because of this reason APF is applied
every 30 sec and the teeth have to be kept wet for 4 min

38.  ADVANTAGES
 Requires only 2 application in a year;
 The gel preparation can be self applied and thus the
cost of application also gets reduced;
 It has the ability to deposit fluoride in enamel to a
deeper depth;
 DISADVANTAGES :
 Practical difficulties like the teeth should be kept wet
for for 4 minutes;
 It is acidic, sour and bitter in taste;
 It cannot be stored in glass containers.

39. 4) AMINE FLUORIDE
 They are cariostatic agents
 Some of them are surface active agents i.e. they have
an affinity for enamel and thus will hold the fluoride
for a longer time against the tooth
 They also have anti bacterial properties. Reduced
plaque formation and anti glycolytic activity is also
reported with these compounds
 Amine fluorides have been tested in dentifrices,
mouthrinses and topical gels where they are either
brushed on teeth or applied with a tray but it is not
known if they are superior to the other currently
available fluoride agents

40. Characteristics Sodium fluoride Stannous
fluoride
Apf
Percentage 2% 8% 1.23%
Fluoride
concentration
(ppm)
9200 19500 12300
ph neutral 2.4-2.8 3.0
Frequency of
application
4 at weekly
intervals 3,7,11 &
13 yrs
biannually biannually
Adverse effects no Tooth
pigmentation
Gingival
irritation
no
Caries reduction 30% 32% 28%

41. RECOMMENDATIONS FOR TOPICAL
APPLICATION
 No more than 2 g of gel per tray or approximately
40% of tray capacity.
 Pt. may have the need to swallow during the 4min
procedure, saliva ejector is recommended.
 After the procedure the pt. be instructed to
expectorate thorougly for from 30sec to 1min.

42. SELF APPLIED TOPICAL
FLUORIDES
 Dentifrices
 Mouth rinses
 Gels
 DENTIFRICES
 The first clinical trial of fluoride dentifrice was
initiated by Bibby in 1942
 The various compounds used in dentifrice are sodium
fluoride, stannous fluoride, monofluorophosphate and
amine fluoride
 A 200g tube of Colgate contains 1000ppm of fluoride
with the fluoride compound as Monofluorophosphate

43.  A single brushing with a full ribbon of paste on
a brush head provides about one gram of
toothpaste and will expose the individual to
approximately 1mgF
 For young children non fluoridated and non
abrasive toothpaste is recommended till the
child is 4 years of age
 After 6 years of age fluoridated toothpaste
should be used
 The amount should be pea sized and the paste
should be pressed into the bristles and not on
top of the brush

44.  MOUTHRINSES
 Fluoride mouthrinsing is one of the most widely used
caries preventive public health methods
 Caries preventive agents used are Neutral sodium
fluoride, Acidulated phosphate fluoride and Stannous
fluoride

45.  Sodium fluoride mouthrinses
 Formulated at concentrations of
0.2%(900 ppm F) for weekly use
0.05%(225 ppm F) for daily use
 These are used by forcefully swishing 10ml of the liquid
around the mouth for 60 sec before expectorating it
 Recommendations for fluoride mouthrinses
 Rinse and expectorate technique used for patients in
fluoride deficient communities
 In patients with increased caries risk e.g. those undergoing
orthodontic treatment or radiotherapy

46.  FLUORIDE GELS
 Fluoride gel products include neutral
sodium fluoride and acidulated
phosphate fluoride with a fluoride
concentration of 5000 ppm and
stannous fluoride with a
concentration of 1000 ppm
 The gels are either applied in trays or
brushed on teeth
 Professionally applied – given twice
a year
 Self applied – once a day or more
 Home fluoride gels are not
recommended for children below 6
yrs and younger

47. Limitations of fluoride gels
 They violate the principle of delivering low
concentration of fluoride at regular intervals
 Toxicity hazard
 Tedious to use on daily basis

48. Conclusion
 Fluoridation is universally accepted by the dentists
and other medical professionals as being useful in
preventing tooth decay
 They can be used in areas where there are no
central water supplies, where the fluoride conc. of
well water is low
 Topically applied fluoride has more effect
compared to systemic fluorides
 Topical fluorides are more economical.
 But cannot be done on a large basis