Fluoride compounds are commonly used in preventive dentistry to reduce tooth decay. Sodium fluoride, stannous fluoride, and acidulated phosphate fluoride are three compounds discussed. Sodium fluoride is applied using the Knutson technique in a series of 4 appointments to deposit fluoride onto the teeth. Stannous fluoride is prepared as an 8% or 10% solution and applied using the Muhler technique every 6 months. Acidulated phosphate fluoride is prepared as an aqueous solution or gel and applied using a tray for 4 minutes every 6-12 months. Fluoride works to strengthen enamel, remineralize early caries, and interfere with bacteria to help prevent tooth decay when used appropriately.

1. TOPICAL
FLUORIDE
REBEKAH M JAMES,
FINAL YEAR.

2. Contents
Introduction.
Mechanism of action of fluorides.
Compounds used in Preventive dentistry.
Conclusion.
Reference.
Previous year questions.

3. Introduction
 To assess the prevalence and type of fluorosis among children from
randomly selected villages of Chhattisgarh.
 A community based door-to-door survey in the year 2013-14. The
fluoride concentration in drinking water was estimated.
 The prevalence of fluorosis ranged between 12 to 44% in children
of surveyed districts. The fluoride levels in drinking water of
selected villages were in the range of 0.1-9.0 ppm.
 Dental and skeletal fluorosis is endemic among children in the
surveyed district.

4. MECHANISM OF ACTION
INCREADED ENAMEL
RESISTANCE/
REDUCTION IN
ENAMEL SOLUBILITY
INCREASED RATE OF
POSTERUPTIVE
MATURATION
REMINERALIZATION
OF INCIPIENT
LESIONS
INTERFERENCE WITH
MICROORGANISMS
MODIFICATION IN
TOOTH
MORPHOLOGY

5. Increased enamel resistance Or
Reduced enamel solubility.
– Dissolution of enamel by acids from bacterial plaque.
– When F is applied it interacts with the hydroxyapatite crystals to
form fluorapatite.
– It is less soluble and act as protective layer and increases enamel
resistance.

6. Increased rate of post eruptive
maturation.
– Hypomineralised areas.
– More prone to dental caries.
– F will increase the rate of mineralisation of these areas.

7. Remineralization of incipient
lesions.
– Remineralization is the deposition of minerals into previously
damaged areas of the tooth.
– This reduces enamel solubility and increases resistance.

8. Interference with
microorganisms.
– It interferes with oral bacteria in 2 ways:-
BACTERICIDAL BACTERIOSTATIC

9. Modification in tooth morphology.
– Amount of F ingested during tooth development and the incidence
of dental caries.
– Deep and narrow pits – dental caries.
– Produce shallow pits.

10. COMPOUNDS USED IN
PREVENTIVE DENTISTRY
– NEUTRAL SODIUM FLUORIDE
– STANNOUS FLUORIDE
– ACIDULATED PHOSPHATE FLUORIDE (APF)

11. NEUTRAL SODIUM FLUORIDE
– First F compound to be used as topical application.
– Min of 4 application needed.
– 2% NaF – 30% reduction in caries.

12. Mechanism of action
– NaF reacts with hydroxyapatite crystals to form CaF.
– CaF formed interferes with the further diffusion of F from the
solution with the hydroxyapatite crystals and blocks the further
entry of F. there is a sudden stoppage of re-entry of F.
– F then slowly release from this CaF.
– CaF reacts with hydroxy apatite crystals to form fluoridated
hydroxy apatite.
CHOCKING OFF EFFECT

13. Method of preparation
– Dissolving 20g NaF powder in 1liter of distilled water.
– Plastic bottle(silica of glass + F=silicon fluoride). Thus reducing
the availability of free active fluorides for anticaries action.

14. Method of application
– Treatments are given in a series of 4 appointments.
– 1st app-
– 2nd, 3rd and 4th app. Is scheduled at an interval of 1 week.
– Recommended ages- 3, 7, 11, 13
KNUTSONS
TECHNIQUE
CLEAN THE TOOTH ISOLATE AND DRY
APPLY SODIUM
FLORIDE 2%-
COTTON TIP
APPLICATORWAIT FOR 3-4
MIN
REPEAT

15. Stable solution-plastic
container.
No need to prepare fresh
every time.
Taste is well accepted by
patients
Non irritating to gingiva.
Does not cause
discoloration to tooth
structure.
Frequent visit to the
dentist in a relative
short period of time

16. STANNOUS FLUORIDE
– 2 concentrations are commonly used.
8% 10%

17. Mechanism of action
– LOW CONCENTRATION
– HIGH CONCENTRATION
– CaF reacts with hydroxyapatite crystals to form
Fluorhydroxyapaptie.
TIN HYDROXYPHOSPHATE
CALCIUM TRI-FLUORO STANNATE
TIN TRI-FLUORO PHOSPHATE
CALCIUM
FLUORIDE

18. Method of preparation
– 0.8grams +10ml of distilled water = 8%stannous fluoride.
– Unstable solution.
– Mixed solution- cloudy due to formation of Tin hydroxide.

19. Method of application
– Next application is made at 6 months interval.
TOOTH IS CLEANED ISOLATE & DRY
SnF IS APPLIED-PAINT
ON TECHNIQUE
WAIT FOR 4 MIN
MUHLER’S
TECHNIQUE

20.  6-12 months interval, so
it conforms to the usual
dentist’s patient recall
system.
 Administrative
difficulties is avoided.
Not stable in aqueous
solution.
Unpleasant taste.
Occasionally cause
tissue irritation.
Cause pigmentation of
teeth-light brown color.

21. ACIDULATED PHOSPHATE
FLUORIDE
– Brudevolt and his coworkers at Massachusetts in 1960’s.

22. Mechanism of action
DEHYDATION & SHRINKAGE OF THE CRYSTALS.
FLUORIDE ENTERS INTO THE OPENINGS AND FORMS
FLUOROAPETITE.
FURTHER HYDROLYSIS FORMS DCPD.
DEPTH OF PENETRATION DEPENDS UPON HOW DEPTH DCPD IS
FORMED.
DICALCIUM PHOSPHATE DIHYDRATE
{DCPD}

23. Method of preparation
Two forms:
– Aqueous solution
– Gel form

24. Aqueous solution-
 20 grams of NaF+ 1 litre of 0.1M phosphoric
acid+50%hydrofluoric acid.
– Hydrofluoric acid pH at 3 and F ion concentration at 1.23%.
BRUDEVOLD’S
SOLUTION

25. Gel form-
– To the sol methylcellulose or hydroxyethyl cellulose is added.
– pH 4-5

26. Method of application
– Aqueous sol is applied by paint on technique
– Gel preparation by tray technique.

27. ORAL
PROPHYLAXIS
ISOLATE
AND DRY
GEL
APPLIED
USING
TRAY
REAPPLIED
EVERY 15-
30 SEC
4 MINUTES

28. – Patient is in supine position.
– Trays should be properly positioned and saliva ejector is used.
– Ask the patient to exert slight pressure using cheeks and tongue as
well as slight biting force so as to allow the gel to flow
interproximally.
– Should not eat or drink or rinse at least for 30 min.
– 6-12 months interval.

29. 2 applications in a year.
Self-applied.
Cost of application is
reduced.
Has an ability to deposit F
in enamel to a deeper
depth.
Stable.
Practical difficulties.
Acidic, sour, and bitter.
Cannot be stored in glass
containers.
Repeated or prolonged
exposure to porcelain or
composite-loss of
material.

30. Conclusion
– When used appropriately, F is a safe and effective agent that can be
used to prevent and control dental caries.
– F has contributed profoundly to the improved dental health to
persons all over the world.
– F is needed regularly throughout life to protect teeth against tooth
decay.
– To ensure additional gains in oral health, water fluoridation should
be extended to additional communities and F toothpastes should be
used wisely.

31. Reference
 Essentials of Public Health Dentistry : Soben Peter-6th edition

32. Questions
– ESSAYS
1) What are the various fluoride delivery methods. Describe in detail
about various topical fluoride compounds used in preventive
dentistry (4+10) (July 2019).
2) What are the advantages of fluorides. Describe the various ways
of using fluorides in dentistry (RGUHS-April 2010) (15marks)
3) What are the mechanism of action of fluoride in caries reduction.
Discuss various professionally applied fluoride delivery methods
in details(RGUHS-Dec 2013)

33. Questions
– SHORT ESSAYS
1) Mechanism of action of sodium fluoride(RGUHS-Dec2012)

34. Questions
– SHORT NOTES
1) Knutson’s technique(Aug 2014) (Feb 2016) (Feb 2018) (Jan 2018)
2) Acidulated phosphate fluoride (Aug 2016) (July 2016)
3) Topical Fluorides (RGUHS) (Nov 2010)