1. PEDODONTICS 1-7
Dr. Abdullah Abumoamar

2. Fluorides

3. Fluorides
Fluoride is one of the essential agents used in preventive dentistry effective against dental caries .
Fluoride is derived from a Latin word fluor, meaning to flow, since it was used as a flux.
It is most electronegative with atomic weight 19 and atomic number 9.

4. Fluorides
It has also been described as an essential nutrient in the Federal Register of United States Food and Drug Administration (1973) and also
by WHO expert committee

5. Fluorides
1901: Dr Frederick McKay of Colorado, USA discovered permanent stain on the teeth of his patients which was referred to as “Colorado brown stain.” McKay named the stain as mottled enamel.
1902 :Dr JM Eager, a US marine hospital surgeon, stationed in Italy reported a high proportion of Italian residents in Naples who had ugly brown stains on their teeth known as ‘denti di chiaie.’

6. Fluorides
1916: McKay and Black examined 6873 individuals in USA and reported that an unknown causative factor of mottled enamel was possibly present in domestic water during the period of tooth calcification.
1930 Kemp and McKay observed that no mottling occurred in people who grew up in bauxite prior to 1909, the year in which bauxite had changed its supply from shallow wells to deep drilled wells.

7. Fluorides 1935: Dean gave his mottling index 1 ppm—no stain
2.5-3 ppm—dull chalky appearance
4 ppm—discrete pitting

8. Fluorides
Fluoride is found in abundance in the nature and is distributed in the :
biosphere (Few plants like tea plants actively accumulate fluoride and the fluoride concentrations reach between 0.03–25.7 ppm fluoride)
hydrosphere (Sea water contains 1.2–1.4 ppm fluoride 47% of which are present as MgF )
Atmosphere (industrial area )

9. Fluorides lithosphere : Some of the fluoride containing minerals are
Apatite, 34% of fluoride Ca5(PO4)3(OH,F,Cl)
Cryolite, 54% of fluoride Na3AlF6
Fluorite 49% of fluoride CaF2

10. Fluorides
The rate and amount of fluoride absorption are determined by many factors:
Physical form of the dose: Fluoride in the liquid form is better and quickly absorbed than in the solid form.
Presence of food in the stomach: Fluoride absorption is slow in the presence of food.

11. Fluorides
Composition of gastric contents: Certain items such as milk combine with fluoride and delay its absorption.
Gastric pH: Reducing the pH enhances the fluoride absorption. Ionic fluoride is converted to hydrogen fluoride, which is a weak acid and an uncharged molecule that freely passes through gastric membrane

12. Fluorides
Gastrointestinal motility: Fluoride absorption is reduced with increased motility as seen in case of diarrhea.
Concurrent oral administration of cations like Ca, Mg, Al: They bind with fluoride thus making it unavailable for absorption.

13. Fluorides Distribution of fluoride in the body : Fluorides in plasma
It exists in 2 general forms
1. Ionic (also called as inorganic or free fluoride)
2. Nonionic (bound fluoride)
Together they form the total plasma fluoride and are about 12 µm/L.
Plasma half-life for fluoride is about 4-10 hours.

14. Fluorides Distribution of fluoride in the body :
Fluorides in soft tissues :
It mainly depends upon the blood flow to the tissue.
The brain tissue and the adipose tissue accumulate the least amount
the kidney, heart and lungs accumulate the maximum amount of fluoride

15. Fluorides Distribution of fluoride in the body : Fluorides in teeth :
Fluoride concentration in enamel is not uniform.
Outer enamel concentrates more fluoride than the inner layers.
In dentin the concentration of fluoride is more at the pulpal end.
Cementum accumulates the maximum amount of fluoride.

16. Fluorides Distribution of fluoride in the body : Fluorides in teeth :
Amount of fluoride in the tooth
Outer enamel—2,200-3,200 ppm
Dentin— ppm
Cementum—4,500 ppm

17. Fluorides Distribution of fluoride in the body : Fluorides in bone :
More than 95% of the fluoride in the body is retained in the bones and this retention is irreversible. When the intake falls
fluoride from the bones are released into the plasma and later excreted.

18. Fluorides Distribution of fluoride in the body :
Accumulation in bones depends on:
• The fluoride intake: Amount of fluoride accumulated is directly related to the amount of fluoride intake.
• Type of bone: Cancellous bone retains more fluoride than compact bone.

19. Fluorides Distribution of fluoride in the body :
Accumulation in bones depends on:
• Age: Fluoride accumulation is maximum in growing bones.
• Duration of fluoride exposures: Amount of fluoride accumulated is directly proportional to the duration of exposure to fluoride.

20. Fluorides
Fluorides are deposited in dental tissues in successive stages during the life of the tooth.
The initial deposition occurs while the organic and mineral phases are being laid down.
Next it is deposited from the tissue fluids during the pre-eruptive maturation phase.
Finally fluoride is acquired topically during posteruptive maturation and aging period

21. Fluorides Excretion of fluoride :
Excretion through the kidneys forms the major route for the elimination of fluoride. Renal clearance of fluoride is about ml/min.
About 30% is excreted within 3 hours and remaining 40-60% is excreted within 24 hours.
Increase in urine pH increases the fluoride excretion

22. Fluorides Excretion Remaining fluoride is excreted through
the feces (10%)
Breast milk ( ppm),
Sweat (10-25%)
saliva ( ppm).

23. Fluorides
Hypothesis regarding fluoride anticaries mechanism of action:
Effect on hydroxyapatite crystals
Decreasing its solubility
b. Improving its crystallinity
c. Remineralization

24. Fluorides
Hypothesis regarding fluoride anticaries mechanism of action:
2. Effect on bacteria
Inhibiting enzymes
b. Suppressing cariogenic flora

25. Fluorides
Hypothesis regarding fluoride anticaries mechanism of action:
3. Effect on the enamel surface
a. Desorbing protein/bacteria
b. Lowering the free surface energy
4. Alteration of the tooth morphology.

26. Fluorides Effect on hydroxyapatite crystals :
Decreasing its solubility
Fluoride reduces the solubility of hydroxyapatite crystals during acid attack.
fluorapatite is less soluble than hydroxyapatite: Ca10(PO4)6OH2 + Fl = Ca10(PO4)6Fl2

27. Fluorides Effect on hydroxyapatite crystals :
b. Improving its crystallinity:
Fluorides increase the crystal size and produce less strain in the crystal lattice.
This takes place by conversion of amorphous calcium phosphate to crystalline hydroxy- phosphate.

28. Fluorides Effect on hydroxyapatite crystals : c. Remineralization:
It is a process of deposition of apatite or like material in enamel and dentin tissues after partial loss of normal mineral.
Fluoride stimulates apatite precipitation.
Frequent application of low level fluoride will effectively inhibit demineralization and enhance remineralization

29. Fluorides Effect on hydroxyapatite crystals : c. Remineralization:
Therefore the best strategy for caries management would be to focus on the methods of improving the remineralizing process.
Various commercial products are available that contain fluorides that aid in remineralization

30. Fluorides 2. Effect on bacteria Inhibiting enzymes
Fluoride has enolase inhibition effects and inhibits glucose transport also.
Thus it inhibits the metalloenzyme

31. Fluorides 2. Effect on bacteria Inhibiting enzymes
It also has shown to inhibit nonmetalloenzymes like phosphatases, acetylcholinesterase, etc.
All the above effects are interrelated through PEP (Phospho Enol Pyruvate) phospho transferase system that is found in S. salivarius, S. mutans, S. sanguis.
This leads to reduced acid production and reduced glucose transport into the cell.

32. Fluorides 2. Effect on bacteria b. Suppressing cariogenic flora
Fluoride suppresses the growth of bacteria.
Stannous fluoride is more potent.
Stannous ion oxidizes the thiol group present in the bacteria required for its metabolism.

33. Fluorides 3. Effect on the enamel surface
a. Desorbing protein/bacteria
Hydroxyapatite crystals are amphoteric with both positive and negative receptor site. Acidic protein group binds at calcium site and basic protein groups bind at phosphate site. Fluoride inhibits the binding of acidic protein to hydroxyapatite.

34. Fluorides 4. Alteration of the tooth morphology.
Dentition in fluoridated communities show a tendency towards rounded cusps, shallow fissures, wider tooth and improved alignment.
All these make the tooth at less risk for development of caries.

35. Different modes of fluorides administration
Systemic: In this mode fluoride is taken in a dietary form.
Fluoride is absorbed into the circulation and reaches the developing teeth.
Fluoride is also secreted into the saliva and gingival crevicular fluid.

36. Different modes of fluorides administration
2. Topical:
They are moderate to high concentration fluoride applied topically on the tooth surface.

37. Systemic fluorides 1. Water fluoridation 2. Salt fluoridation
3. Milk fluoridation
4. Fluoride tablets.

38. Systemic fluorides 1. Water fluoridation :
“Controlled adjustment of the concentration of fluoride in a community water supply so as to achieve a maximum caries reduction and a clinically insignificant level of fluorosis.”

39. Systemic fluorides
1. Water fluoridation : In US and Canada, studies on fluoridation of water began in 1945.
The results of these studies were as follows:
• Fluoride is the etiological factor for the observed low caries levels in areas with naturally fluoridated drinking water
• There is no difference between the effect of naturally and artificially fluoridated water

40. Systemic fluorides
• Controlled addition of fluoride to water is technically possible within narrow limits.
• When fluoridation was discontinued in a community, there was a dramatic increase in the dental caries incidence.

41. Systemic fluorides 1. Water fluoridation :
Caries reduction benefits to primary teeth was 40-50% and to the permanent teeth was 50-60%.
Fluoride benefit is not uniform and varies depending on tooth surfaces:
Buccal and lingual—85%
Inter proximal—75%
Pit and fissures—35%

42. Systemic fluorides 1. Water fluoridation :
Optimum concentration of fluoride in the drinking water to produce maximum anticaries benefit and minimum toxicity
This varies according to the climatic condition
In the tropical climates, water consumption is more than in cold climates and hence the amount of fluoride added to drinking water must be less than in cold climatic region.

43. Systemic fluorides 1. Water fluoridation : Recommended= 0.7 to 1.2 ppm
(0.7 ppm in tropical climate and 1.2 ppm in cold climate).

44. Systemic fluorides Advantages of Water Fluoridation :
• As people drink water daily, fluoride is consumed along with it
• Large number of people can benefit
• Cheap and effective

45. Systemic fluorides Disadvantages of Water Fluoridation :
Interfere with human rights and fundamental liberties that every individual whether one likes it or not should consume fluoridated water.
• Other modes of fluoride intake should be considered. There is increased risk of overdosage of fluoride in individuals consuming other fluoride supplements.

46. Systemic fluorides Disadvantages of Water Fluoridation :
• The entire population should consume water from one source. Fluoridation is not possible in area where people drink water from their individual well or rivers.

47. Systemic fluorides School Water Fluoridation :
It is a suitable alternative, where community water fluoridation is not feasible.
Children can benefit by drinking fluoridated water when fluoride is added to the school water tank.

48. Systemic fluorides School Water Fluoridation :
The amount of fluoride added to the school water is more as they spend only 20-25% of their total working hours in school.
The recommended level of fluoride is 4.5 times that of the optimum level.

49. Systemic fluorides Disadvantages of school water fluoridation :
- Children are already 5-6 years when they attend the school.
- Benefits of systemic fluoride are maximum during the developing stages of fluoride.
- Most of the tooth crowns would have already formed by then they are relatively less beneficial.

50. Systemic fluorides Disadvantages of school water fluoridation :
- Continued monitoring of water is required.
-School authorities should hire a person who is well informed regarding the risk associated with adding excess fluoride to the water.
- He should monitor the total activity regularly..

51. Systemic fluorides
Different fluoride compounds used for water fluoridation
Sodium fluoride was used initially and is expensive.
2. Fluorosilicic acid (hydrofluorosilicic acid)—it is corrosive and requires careful supervision.
3. Fluorspar (calcium fluoride)—it costs 1/3 as much as sodium silicofluoride, but difficult to dissolve.

52. Systemic fluorides
Different fluoride compounds used for water fluoridation
4. Ammonium fluosilicate.
5. Sodium silicofluoride.
Sodium silicofluoride is preferred alternatively due its low cost.

53. Salt fluoridation Introduced in Switzerland (1955) by Wespi.
Initially 90 mg fl/kg salt was used,
later it was increased to mg fl/kg of salt.
Clinical trials in Switzerland, showed 20-25% reduction of caries with 90 mg of fluoride.

54. Salt fluoridation
It was then decided that to obtain the same amount of fluoride benefit as water fluoridation,
the amount in salt has to be increased to 300 mg/kg yielding 1.5 mg fl/5 gm of salt.

55. Salt fluoridation
In Switzerland and Hungary fluoride is added by spraying concentrated solution of sodium fluoride or potassium fluoride to salt on a conveyer belt.
In USA sodium fluoride and calcium fluoride are first mixed with a suitable phosphate carrier salt and these premixed granules are added to the salt.

56. Advantages of salt fluoridation
• Individualized monitoring is not required, as the levels are adjusted to provide optimum levels of fluoride, keeping in account that a person consumes 5-8 gm of salt per day
• Everyone consumes salt, irrespective of ethnic or regional variation
• Readily acceptable, as the addition of fluoride to salt does not change the color, odor, consistency or taste.

57. Disadvantages of salt fluoridation
• Special plant has to be set up for fluoridation of the salt
• Consumption of fluoridated salt in areas with increased fluoride concentration in drinking water may lead to overdose.

58. Milk fluoridation Milk fluoridation :
It was first mentioned by Zeigler in % caries reduction was observed with 2.5 mg of sodium fluoride added to milk daily in school meals
There was a controversy concerning the binding and complexing of fluoride with calcium and milk protein thus reducing its anti caries effect.

59. Milk fluoridation
Erickson (1958) using radioactive isotope technique proved the availability of fluoride from milk. But the release of fluoride from milk is mild and slow compared to that from water

60. Disadvantages of Milk fluoridation
• In most of the rural areas there is no central milk supply, hence fluoridation is not possible.

61. Fluoride tablets
It was introduced in the late 1940’s intended to be used as a substitute for fluoridated water.
Fluoride tablet is prescribed by a dental practitioner for individual patients keeping in account the fluoride concentration in the drinking water and other fluoride supplements consumed.

62. Fluoride tablets • Tablets or drops to be swallowed, chewed or sucked
• Tablets available as
0.25 mg,
0.5 mg,
1.0 mg
• Sodium fluoride, acidulated phosphate fluoride, potassium fluoride or calcium fluoride.

63. Fluoride tablets
Dosage: It is calculated keeping in mind the water fluoride level of the community
Less amount of fluoride in tablet form is recommended for children residing in areas having increased level of fluoride in drinking water.

64. Fluoride tablets
Therefore for children residing in areas where the drinking water level of fluoride is more than 0.6 ppm, fluoride supplement is not required.

65. Fluoride tablets Age < 0.3 > 0.3 < 0.6 >0.6 0-6 months -
6 month-3 years
0.25 mg
3-6 years
0.5 mg
6-16 years
1.00 mg

66. thank you