1. Reactions, advantages, methods of delivery
fluoride
Reactions, advantages, methods of delivery

2. Session outline Fluoride reactions in oral environment
Advantages of use of fluoride
Methods of distribution
Fluorosis

3. Fluoride reactions in oral environment
Formation of fluorohydroxyapatite
Formation of calcium fluoride

4. Fluoride concentration in solution is low Less than around 50ppm
Fluoride reactions in oral environment Formation of fluorohydroxyapatite
When
Fluoride concentration in solution is low
Less than around 50ppm
In the acidic environment
Ca10(PO4)6(OH)2+F- +H+
Ca10(PO4)6(OH) F+H2O

5. Fluoride reactions in oral environment Fluorohydroxyapatite
Will be situated in outermost layers of enamel
Will form integral part of the tissue
Its formation is slow, unable to keep pace with normal wear of the tooth structure

6. Fluoride reactions in oral environment Fluorohydroxyapatite
In approximal areas the fluoride content of the surface enamel increases over lifetime
On smooth enamel surface the fluoride content is reduced by wear and abrasion

7. Fluoride reactions in oral environment Fluorohydroxyapatite
Conditions
Oral fluids, saliva, plaque fluid should be supersaturated in respect to fluoroapatite
pH above 4.5

8. Fluoride reactions in oral environment Formation of calcium fluoride
When concentration of fluoride in the solution is above 100ppm
Happens when topical fluoride treatment is performed
The higher fluoride concentration more calcium fluoride is formed
Ca10(PO4)6(OH)2+20F- +8H+
10 CaF2 + 6 HPO H2O

9. Fluoride reactions in oral environment Formation of calcium fluoride
Low pH considerably increase dissolution of hydroxyapatites
Thus provides Ca 2+ presence
also formation of calcium fluoride is increased

10. Fluoride reactions in oral environment the role of calcium fluoride
Calcium fluoride precipitates
on sound enamel surfaces
On plaque
other inaccessible stagnation area
CaF will slowly dissolve
Has preventive effect maintaining good concentration of fluoride in the near surroundings

11. Fluoride preventive action against caries
Formation of fluorohydroxyapatites which are more acid resistant
Formation of calcium fluoride which provides reservoir of fluoride ions
fluoride ions provide remineralization
have anti plaque effect

12. Fluoride reactions in oral environment crystal dissolution
All minerals have fixed solubility in water
Dissolution is relatively fast at first
Slows as ions making up the crystal accumulate in solution
Solution is saturated with respect to the mineral
Slow exchange of ions between crystal and solution occurs

13. Fluoride reactions in oral environment crystal dissolution
Ca2(PO4)3OH Ca 2+ +3PO4 3- +OH –
PO4 3- , OH – , Ca 2+ ions accumulate in solution
Dissolution slows and stops as the solution becomes saturated with ions

14. Why the dissolution of the ion is increased in acid?
If acid is added
PO43- ions , OH– ions combine with H+ to form HPO42- ions and H2O
Thereby removing a portion of PO4 3- ions and OH- ions from the solution
The solution is then unsaturated and more hydroxyapatites dissolve until saturation is re-established

15. Fluoride reactions in oral environment Critical pH
The point at which the solution becomes just saturated with respect to the mineral
For hydroxyapatites is 5.5
For fluorohydroxyapatites is

16. Fluoride preventive action against caries remineralization
Demineralization
Under normal conditions oral fluids are supersaturated with respect to both hydroxyapatite and fluoroapatite
As pH is lowered below pH critical the supersaturated status is reduced and replaced by unsaturated

17. Fluoride preventive action against caries remineralization
Because pH critical for hydroxyapatites is 5.5 the solution becomes unsaturated with respect to it faster than with fluoroapatites(pH critical 4.5)
Between these two pH
Hydroxyapatites dissolve in oral fluids-because fluids are unsaturated with respect to it
Fluoroapatites are formating on the surface of enamel

18. Fluoride preventive action against caries remineralization
Demineralization occurs in subsurface region
Formation of fluoroapatites occurs on surface
The formation of fluoroapatites is responsible
for the maintenance of integrity of surface layer
For less soluble mineral creation

19. Fluoride preventive action against caries Anti plaque action
Competitive inhibition of saliva proteins adhesion to the enamel surface
Thanks to the characteristic of F- ion which is very active
Has potential for binding Ca ion on the surface of enamel
Thus inhibits adhesion of acidic proteins to the enamel
Becouse the formation of the plaque on the base of pellicle is specific F- (special bacteria bind with special proteins on the tooth structure) can alter the plaque composition

20. Fluoride preventive action against caries Anti plaque action
Fluoride ion easly gets into the bacterial cell
As the active agent has the potential to block enzyme enolase which hydrolizes corbohydrates
Thus blockege of metabolism of bacteria has antimicrobial action

21. Fluoride preventive action against caries Anti plaque action
Fluoride ion has also the potential of blockege of formation the extracellular policarbohydrates
They create the reservoir of the carbohydrates for bacteria
They are crucial for survival in periodes of time when bacteria can not obtain the energy from saliva
They are also the very important component of plaque composition

22. Fluoride methods of delivery
Systemic
Topical
Primary mode of action of fluoride is the result of its activity in the oral cavity and is little benefit from swallowing it.

23. Fluoride methods of delivery
Systemic
Water
Supplements
Milk
Salt

24. Fluoride methods of delivery
Topical
Toothpaste
Gels
Varnishes
Paint-on applications
Mouthrinses

25. Fluoride methods of delivery Systemic administration
Water can contain 1mgF/l mining 1ppm
Provides widespread penetration into the population without individual effort
Is effective and save
Coutries with water fluoridation
USA, Canada, UK, Brazil, Australia, New Zealand, Ireland
Most effective and cheapes way to provide fluoride supplementation

26. Fluoride methods of delivery Systemic administration
Salt
The salt consumption is variable between families
Resulting in the risk of fluorosis when consuption is in large amounts

27. Fluoride methods of delivery Systemic administration
Milk
Administration of fluoride by milk has an advatage over water fluoridation that can be targeted directly at segments of population deemed to be at risk
In school intervations

28. Fluoride methods of delivery Systemic administration
Fluoride supplementation with drugs
Floride concentration in drinking water
6 months -3 years
3-6 years
6-16 years
Less than 0.3 ppm
0.25mg
0.5mg
1mg
ppm
0mg
More than 0.6ppm

29. Role of fluoride incorporated during development for tooth structure
Fluoride ions become incorporated into the mineral tooth structure if they are present in the environment
They create fluoroapatites which are more resistant minerals toward pH drops
they activate the process of formation apatites
They also help in formation shallow fissures thus the tooth is much easer to clean

30. Fluoride methods of delivery Self-applied methods
Fluoride toothpaste
Gels
Mouthrinses

31. Fluoride methods of delivery self-applied methods
Toothpaste
The fluoride concentration is between ppm
Mouthrinses
0.2% NaF typically 10ml for 1min

32. Fluoride methods of delivery proffesional delivery methods
Gels, foams
Contain higher concentration of fluoride
ppm
Applicated in the dental office
Usually twice a year
It is recommended to sit up the patient, and prevent swallowing, with suction

33. Fluoride methods of delivery proffesional-applied methods
Varnish
Appication twice a year
Provide high uptake of the fluoride ion into the enamel p.e. Duraphat ppm
Clinician applies a thin layer of the varnish directly on the teeth
Application time is several minutes
Patients are to avoid eating for several hours and than avoid brushing until next morning

34. Fluoride consisting materials
Materials in which fluoride is the integral part of the material: glassionomers
In which fluoride is added for anti-caries action : resin-modified glasionomers, compomers, composites(Tetric Ceram, Tetric Flow)

35. Fluoride consisting materials
Can be the reservoir for fluoride in the oral cavity environment
They can increase remineralization
Decrease demineralization
Fluoride secretion can occure for 8 years

36. Fluoride consisting materials
Glassionomers
Can be placed on demineralized(afected) dentin in after preparation and studies show mineralization and even hipermineralization of that dentin

37. Fluoride consisting materials
We use GI when strong anti-caries effect is to be achived during for ex. Atraumatic restorative techniques
RMGi we use when slow liberation of the low fluoride is needed for anticaries action
composites,compomers for its better chemical and phisical resitance and liberation of fluoreide is less important