1. FLUORIDE USE IN DENTISTRY
DR BAKARE

2. Outline Introduction History Natural Sources Of Fluoride
Physiology and metabolism of fluoride
Fluoride in Dentistry
Control of dental caries
Fluoride toxicity
Dental fluorosis
Fluorosis indices
Water defluoridation
Conclusion

3. Introduction
Fluoride is a mineral and Fluoride ion comes from the element fluorine.
Fluorine is 17th most abundant element in the earths crust.
Highly reactive, hence never encountered in its free state in nature.
Exits only in combination with other elements as a fluoride compound

4. Constitutes about 0.032% in earth’s crust
The name Fluorine is derived from
The Latin word “fluore” meaning “to flow”.
Greek “floris”- destruction

5. Brief History of Fluoride in Dentistry
Frederick McKay in 1901 noted characteristic mottling stains on teeth of children who had spent all their life in Colorado known as Colorado brown stain
G.V Black and others found that other regions in the USA has similar mottling, and histological exam show that enamel was imperfectly calcified. No difference in caries incidence compared with normal teeth.
Mackay suspected the cause to be from the water supply

6. Similar findings in a community formed by house workers of an aluminium company prompted the chief chemist anxious that aluminium should not be blamed, to analyse the water and found a higher than normal concentration of fluoride (about 13.7ppm)
HT Dean in 1938 showed a relationship between tooth mottling and water fluoride level and that mottling disappear or minimal as fluoride fall below 1ppm.
FA Arnold 1953 reported a 50% fall in caries in Grand Rapids compared with control group after 6years of artificially fluoridating water.

7. WHO recommended first time 1 ppm fluoride in drinking water for a practicable and effective public health measure.
WHO has recommended optimum level of fluoride in drinking water as ppm.

8. Fluoride in Nigeria
Data from Nigeria is sparse. Two studies from Plateau state found a prevalence of 26.1% in langtang with 20.6% classified as mild. It reported Fl conc of ppm in streams and ppm in wells(1997)
In 2008, a prevalence of 12.9% was recorded. This study also found higher prevalence in high altitude areas which had lower Fl content of 0.76+/ than the lower altitude areas

9. Natural Sources of Fluoride
In rock and soil-
Fluorspar ( fluorite CaF2)
Fluorapatite {Ca10F2 (PO4 )6}
Cryolite ( Na3AlF6)
In Soil, the fluoride concentration increases with depth.
In Water:
Sea water mg/L.
Lakes, rivers or artesian wells - below 0.5mg/L.
Concentrations as high as 95mg/L have been recorded in the United Republic of Tanzania.

10. In Foods And Beverages:
In Air:
Fluoride is widely distributed in the atmosphere as;
dusts of fluorides-containing soils
gaseous industrial waste
domestic burning of coal fires
gases emitted in areas of volcanic activity
In Foods And Beverages:
Unprocessed foods -low ( mg/kg).
In plants mg/g of dry weight.
Leafy vegetables mg on dry weight basis.
Fish ppm on dry weight basis.

11. In Animals In beverages Beef, pork and mutton-0.3ppm
Higher in Chicken- contained in bone and cartilage fragments
Fish products- up to 20ppm
Dried sea foods also fluoride rich 84.5ppm (South East Asia)
In beverages
Juice, beverages,
Infant formula
Fluoride content in liquid beverages generally reflects that of water used.

12. Total daily intake of Fluoride
Fluoride from Air
Minimal
Fluoride from Water
Most important single source of fluoride
Dependent on fluoride concentration and amount
Fluctuation –climatic and geographical areas
Fluoride from food
0.3 to 0.6 mg/day
Fluoride intake 6months of life-bottle/breast fed
Breast fed infant receives to 0.004mg/day- formula fed infants (1.2ppm) fluoride intake increased 50 times

13. Physiology of fluoride
Ingested fluoride is absorbed mainly from the upper G.I.T.
F ingested on an empty stomach reaches peak plasma level in 30 minutes
Up to 95% of ingested F may be absorbed
Absorbed fluoride is transported in plasma and is either excreted or deposited in the calcified tissues
Most absorbed fluoride is excreted in urine.
Single ingestion of 5mg fluoride by an adult is absorbed and cleared from the blood in 8-9 hrs.

14. Approx. 75% – 90% of ingested F¯ is absorbed
More in liquid diet than in solid (80% in solid, up to 97% in water)
Half-time for absorption is 30 min
Peak plasma concentration – 30 – 60 min.
Ionic form-- relevant to health
Fat soluble form
Calcium in diet reduces absorption
99% of body burden is assoc. with calcified tissues
50% will be assoc. within 24 hr – Rest is excreted through urine

15. Distribution of Fluoride
Teeth and skeleton have the highest concentrations of fluoride -- affinity of fluoride to calcium.
Fluoride content of teeth increases rapidly during early mineralization periods and continues to increase with age, but at a lower rate.

16. Fluoride in Dentistry
The application of fluoride in dentistry can be considered under the following:
Control of dental caries
Fluoride toxicity
Dental fluorosis

17. Fluoride in Caries Control
The effect of fluoride in caries prevention can be considered under two headings.
Pre-eruptive effect
Post – eruptive effect

18. Pre-Eruptive Effect
Improved crystallinity - Changes the crystalline structure of enamel to make it less soluble.
Increased Crystal size
Less acid solubility
More rounded cusps and fissures
Overall effect is small because discontinuation of fluorides leads to increased caries – constant servicing!!!

19. Pre-Eruptive Effect
Changes the crystalline structure of enamel to make it less soluble.
OLD CONCEPT
That major inhibitory effect was thought to be due to its incorporation in tooth mineral during the development of the tooth prior to eruption

20. Recent evidences shows that the main effect of fluoride in caries prevention are the post-eruptive - through Topical effect.
Fluoride incorporated during mineral development at normal levels of ppm does not alter the solubility of the mineral.
Fluoride incorporated developmentally into the normal tooth mineral is insufficient to have a measurable effect on acid solubility.
Only when fluoride is concentrated into a new crystal surface during Re- mineralization, is it sufficient to alter solubility beneficially.

21. Post-Eruptive Effect
Effect is seen when fluoride is present in plaque and saliva.
There is now clear evidence that caries reduction is most effective when a low conc. Of Fl is maintained consistently in the oral environment.
This is in contrast to earlier concept
Attributed the major benefit of Fl to pre-eruptive maturation of forming enamel
Predominant effect is TOPICAL rather than systemic

22. Interferes with glycolysis – Bacteria metabolizing sugars to acid by inhibiting enolase and proton pump ATPase.
Inhibit the glycolytic pathway of oral microorganisms reducing acid production and interfering with the enzymatic regulation of carbohydrate metabolism.
Also reduces the accumulation of intracellular and extra-cellular polysaccharides
This bactericidal action occurs only at higher concentrations.

23. Unionized hydrofluoric acid formed at lower pH values
These inhibitory mechanisms are affected by the hydrogen ion concentration of plaque.
A decrease in pH results in a greater inhibitory action on bacterial carbohydrate metabolism
Unionized hydrofluoric acid formed at lower pH values
which occurs due to

24. Fluoride can not cross the cell wall and membrane in its ionized form(F-) but can rapidly travel through the cell wall and into the cariogenic bacteria in the form of HF.
Fluoride in the presence of plaque bacteria generated acid, travels with the acid into the subsurface of the tooth, adsorb to the crystal surface and protect it from being dissolved.
Once inside the cell ,the HF dissociates again acidifying the cell and releasing fluoride ions that interfere with enzyme activity in the bacterium.Interferes with glycolysis

25. Summary of Fluoride Anti-caries Activities
Fluoride prevents demineralization.
Formation of fluorohydroxyapatite and inhibition of mineral loss from enamel.
Fluoride enhances remineralization
Through formation of a fluoride reservoir and creation of supersaturated solutions.
Fluoride alters the action of plaque bacteria.
At low pH, fluoride combines with hydrogen ions and diffuses into oral bacteria as hydrogen fluoride (HF) Inside the cell HF dissociates, acidifying the cell and releasing fluoride ions that inhibit glycolysis.
Fluoride aids in post eruptive maturation of enamel.
Fluoride reduces enamel solubility.

26. Fluoride Application

27. Systemic fluoride Sources Water and other beverages. Food
Fluoride drops
Fluoride tablets

28. Water Fluoridation
It is the controlled addition of fluoride to public water supply to bring its fluoride concentration up to an optimal level to prevent dental caries.
Also defined as controlled adjustment of the concentration of fluoride in a communal water supply so as to maximize caries reduction and a clinically insignificant level of fluorosis.
It is also an upward adjustment of the concentration of fluoride ion in a public water supply in such way that the concentration of fluoride in the water may be consistently maintained at 1 ppm by weight to prevent dental caries with minimum possibility of causing dental fluorosis.

29. Most effective, safest and cheapest way of reducing caries.
Recommended level of fluoride for community water supply ranges from ppm depending on the mean maximum temperature.
At this level, fluoridated water is odourless and tasteless.
It results in 20-40% reduction of caries over a life time
It does not confer life time immunity

30. WHO recommended (1994)- 0.5 to 1.0 ppm
The adsorption of fluoride to the enamel surface is greatly influenced by concentration and temperature.
Hence the, fluoride concentration in public water supply is adjusted according to the average atmospheric temperature (temperate /tropical region)
WHO recommended (1994)- 0.5 to 1.0 ppm
Simple modified method to determine optimum fluoride concentration and mean annual temperature. Richard et.al

31. The use of water fluoridation dates back to the 1900 following the discovery of the a mystery staining of teeth by Dr. Fredrick Mckay in Colorado Boulder.
Advantages
Most economical and cost effective measure for reduction of dental caries
It is practicable because it requires no individual effort.
Offers both pre-eruptive and post-eruptive effects
Topical effect through release in saliva

32. Disadvantage
It requires an effective and central water supply system
Freedom of choice is removed
Requires a complex infrastructure
Initial capital outlay

33. School Water Fluoridation
Suitable alternative to community water fluoridation
4.5 to 6.3 ppm
Advantages
Effective public health measure-when community water supply is not possible
Disadvantages
5 to 6 years old upon starting school- will not provide pre-eruptive contact
Intermittent fluoride exposure-less than 180 days in a year

34. Salt Fluoridation
The controlled addition of fluoride to domestic salt during manufacture for the purpose of preventing caries.
1st used in Switzerland in 1955
Commonly used material is Potassium Fluoride
Concentration is based on estimate of salt consumption and evaluated by studies of urinary fluoride concentration
Concentration of 250mg/kg salt recommended (250ppm for adults and less for children)
Caries protection may be as good as water fluoridation

35. Salt Fluoridation Advantages Disadvantages Low cost Negligible waste
Ease of implementation
Freedom of choice for individuals
Disadvantages
Fluoride dosages of different age in different regions
Lower salt consumption during tooth forming years
In conflict with general health message of low salt intake for prevention of coronary heart disease

36. Milk Fluoridation First mentioned by Ziegler in 1956
Limited Effect as a public measure
Topical fluoride effect less than water because of binding to calcium or protein in the milk.
Advantages
Need to drink under 14 years of age
Disadvantages
Incompletely ionized in milk
Lower absorption from milk than water
Variation in intake
Requires parental or school efforts
Technical difficulties
Problem in distribution
High cost

37. Dietary Supplement
Can be in form of tablets, drops, in 1.0mg, 0.5mg and 0.25mg preparations
Most of them contain neutral NaF.
Dose is 0.5mg F/day in children ≥ 3yrs
Results in 40-50% reduction in caries experience
Advantages
Effective
Freedom of choice
Disadvantages
Compliance needed for consistency
Risk of over dose is high

38. Topical Fluoride These are placed directly on the teeth.
Some preparations provide a high concentration of fluoride over a short period of time.
Other preparations such as dentifrices provide continuous low concentration of fluoride on the teeth.
Topical fluorides allow for the interaction of fluoride with minerals in the teeth.

40. Indications for Topical Fluoridation
Caries active individuals
Children shortly after the period of teeth eruption.
Those who are on medication which decrease the salivary flow or who have received radiation to head and neck.
After periodontal surgery when the roots of the tooth are exposed.
Patients with fixed or removable prosthesis after placement or replacement of restorations.
Mentally and physically challenged patients.
Patients with an eating disorder or who are undergoing a change in lifestyle which may affect their oral hygiene habits.

41. Rationale for Topical Fluoridation
To speed the rate and increase the concentration of the 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 the adjacent sound tooth enamel.

42. Topical fluorides are divided broadly into 2 main categories

43. 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 ppm which is equivalent to 5-9mgF/ml.
The three agents currently in use are:
1) Neutral Sodium Fluoride (NaF)
2) Acidulated Phosphate Fluoride (APF)
3) Stannous Fluoride (SnF2)

44. Advantages Disadvantages
Effective and useful for individuals at high risk of dental caries
Freedom of choice
Disadvantages
Need for personnel
Time consuming
Requires access to service

45. Indications Contraindications Caries prone children >6 years of age
Patients with initial carious lesions
For nervous patients, varnish is easy to apply
Medically and physically disabled
For early childhood caries
Fluoride varnish can reduce hypersensitivity in root caries
Patients with orthodontic appliances who cannot or will not use fluoride rinses
Patients with reduced salivary flow due to salivary gland dysfunction, drugs or radiotherapy
Contraindications
Due to high fluoride concentration, it is not ideal for home use
Not for children < 6 years who cannot spit out

46. Forms of Topical Fluoride
Aqueous Solutions And Gels
The gel adheres to the teeth for a considerable amount of time and eliminates the continuous wetting of the enamel surfaces required when solutions are used.
When gels are applies using trays, it is possible to treat two or four quadrants simultaneously and saves time.
Each application is loaded by using a thin layer, thereby reducing the risk of accidentally ingesting a large quantity of fluoride.
Thixotropic solutions are more stable at lower pH and do not run off the tray as readily as conventional gels.

47. Advantages of foam based APF agents are:
FOAMS
Foam based agents were developed to minimize the risk of fluoride over dosage as well as to maintain the efficacy of topical fluoride treatment.
Advantages of foam based APF agents are:
It is much lighter than a conventional gel and therefore only a small amount agent is needed for topical application.(4gm of gel/mouth while less than 1gm of foam/mouth).
The surfactant in the foaming agent has cleansing action by lowering the surface tension.

48. It may also facilitate the better penetration of the material into inter proximal surfaces where its action is most needed.
Since APF foams does not require suctioning, it offers advantages for home use as well as treatment of young children and disabled persons where saliva evacuation may not be feasible.

49. It was first developed by Schimdt in Europe in 1964.
FLUORIDE VARNISH
It was first developed by Schimdt in Europe in 1964.
Increasing the time of contact between enamel surface and topical fluoride agents favors the deposition of fluoro-apatite and fluorohydroxyapatite.
Technique Used:
After prophylaxis, the teeth are dried but not isolated since varnish can stick to cotton.
ml of varnish is required to cover full dentition.
Application is done first on lower arch then upper, using single tufted small brush, starting with the proximal surfaces.
Patient is asked to sit with mouth open for 4 min to let it set.
The patient is asked not to rinse or drink for 1 hour.

50. Examples of Fluoride varnish preparations: Duraphat
It is the first fluoride varnish developed in Germany.
It is a viscous yellow material containing 22,600 ppm fluoride as sodium fluoride in aneutral colophonium base.
It has shown 30%-40% caries reduction in permanent dentition and 7%-44% reduction in primary dentition.
Carex
It is also a fluoride varnish containing low fluoride concentration than Duraphat (1.8% fluoride).
It has the efficacy equal to that of Duraphat as caries preventive agent

51. Technique of Application
Knutson’s techniques
At the initial appointment the teeth are cleaned with aqueous pumice slurry and then isolated with cotton rolls and dried with compressed air.
Using cotton tipped applicator sticks, 2% sodium fluoride solution is painted on the air dried teeth so that all tooth surfaces are visibly wet. The solution is allowed to dry for 3-4 minutes.
Advice patient not to eat or drink for the next 30 minutes
The procedure is repeated for each of the isolated segments until the teeth are treated.
A 2nd ,3rd and 4th fluoride application, each not preceded by a prophylaxis, is scheduled at intervals of approx. 1 week.
The four-visit procedure is recommended for 3, 7, 11 and 13 years, coinciding with the eruption of different groups of primary and permanent teeth.

52. MUHLER’S TECHNIQUE commonly for Stannous fluoride application
Each tooth surface is cleaned with pumice or any other dental cleaning agent for 5-10 seconds.
Unwaxed floss is passed between the interproximal areas.
Teeth are isolated and dried with air.
SnF2 is applied using 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.

53. Tray technique The patient should sit upright in the chair.
Oral prophylaxis is done.
The teeth to be treated are completely isolated and dried with air.
Clinical application of APF gels should be done using trays that fit into the patient’s upper and lower arches.
A disposable foam-lined tray is preferred.
To reduce ingestion of fluoride, a minimum amount of fluoride gel that will permit complete coverage of the tooth surfaces should be dispensed. Usually, the amount is less than 5 ml
After the trays have been properly positioned, saliva ejector is used to evacuate the stimulated saliva and excess fluoride.
It is repeated every seconds so as to keep the teeth most with the fluoride solution throughout the four minute period.
The patient should be told not to swallow the gel but to exert slight pressure using the cheeks and tongue as well as light biting force in order to cause the gel to flow interproximally.
The fluoride gel should be in the mouth for 4 minutes and then the remaining oral fluid must be expectorated.
The patient is instructed not to eat, drink or rinse mouth for 30 minutes.

55. Self Applied Low concentration fluoride agents Dentrifices Mouthrinses
Fluoridated toothpaste
Mouthrinses

56. Fluoride toothpaste
The commonest and most widely used.
The simplest method of fluoride delivery.
World wide decline in caries experience has been attributed to widespread use of toothpaste.
Many of the toothpastes contain Sodium monofluorophosphate.
First fluoride dentrifice accepted by ADA in 1964

57. Demonstrated caries reduction of about 30%
The concentration of fluoride in toothpaste varies
The standard and most frequently used toothpaste contains 1,000 to 1,100ppm of fluoride
Toothpastes containing 500 to 550ppm fluoride (pediatric toothpastes)
Recommendations
Containers should be labeled with the concentration of fluoride in ppm
Containers should be designed to limit the amount of paste dispensed
Individuals should brush twice daily

58. Fluoride Mouth rinse Recommendations
Should not be used in children younger than 6 years
Should only be used in high risk children
Appropriate for patients with orthodontic appliances or radiotherapy treatments
Usually formulated at concentrations of either 0.2% for weekly use or 0.05% for daily use.
They are intended to be used by forcefully swishing 10ml of liquid around the mouth for 60 seconds before expectorating it.

59. Fluoride Toxicity Fluoride toxicity can be
Acute
Chronic
Factors that affect toxicity of fluoride
Concentration
Duration of exposure
State of nutrition (calcium, magnesium)

60. Acute toxicity
Acute fluoride toxicity results from rapid excessive ingestion of fluoride at a given time.
Children younger than 6 years account for the vast majority of the cases.
The acute lethal dose for an adult is suggested to be mg F/kg, and in children it is 5mg F/kg.
Certainly lethal dose (CLD): Amount of drug likely to cause death.
Adult = 5-10 g NaF taken at one time or mg F / Kg body weight.
Children = 2.5 g of NaF

61. Once absorbed, fluoride binds calcium ions and may lead to hypocalcemia.
Fluoride has direct cytotoxic effects and interferes with a number of enzyme systems:
It disrupts oxidative phosphorylation, glycolysis, coagulation, and neurotransmission (by binding calcium).
Fluoride inhibits Na+/K+ -ATPase, which may lead to hyperkalemia by extracellular release of potassium.
Fluoride inhibits acetylcholinesterase, which may be partly responsible for hypersalivation, vomiting, and diarrhea (cholinergic signs).
CaSong : Coagulatn. Acetylcholinestares. sodium-potasiumATPase. oxidative phos. Neurotrans. Glycolysis..

62. Acute toxicity Signs and symptoms 2. Electrolyte abnormalities
1.Gastrointestinal signs predominate
Hypersalivation
Nausea
Vomiting
Diarrhea
Abdominal pain
Dysphagia
Mucosal injury
2. Electrolyte abnormalities
Hypocalcemia
Hypomagnesemia
Hyperkalemia
3. Neurologic effects
Headache
Tremors
Muscular spasm
Tetanic contractions
Hyperactive reflexes
Seizures
Muscle weakness
4. Cardiovascular
Widening of QRS
Various arrhythmias
Shock

63. Management of Acute Fluoride Toxicity
Immediate cases:
Aimed at reducing fluoride absorption by inducing vomiting, fluid replacement, monitoring levels of plasma calcium and potassium.
Less than 5mg/kg fluoride ingested
Give milk.
More than 5mg/kg fluoride ingested
Empty the stomach by inducing vomiting.
Give milk, 5% calcium gluconate orally and hospitalization.
More than 15mg/kg fluoride ingested
Immediate Hospitalization, Induce vomiting, Cardiac monitoring, Slow administration of 10% calcium gluconate-IV.
Maintain urinary output-using diuretics if necessary, supportive measures for shock.

64. Chronic toxicity
Fluoride ingested in small doses over a long period time results in changes in the teeth and bone.
These changes are called fluorosis.
Fluorosis
Dental fluorosis
Skeletal fluorosis

65. Dental Fluorosis
Occurs as a result of hypo-mineralization of enamel due to the ingestion of excess fluoride during tooth development.
The severity of fluorosis is dose, duration and time dependent.
The occurrence of enamel fluorosis is most strongly associated with cumulative fluoride intake during enamel development
This is especially during the early maturation stage of enamel development.

66. The time for early maturation (enamel calcification) varies from tooth to tooth
Upper central incisor has the most sensitive period for fluorosis as months for boys and months for girls
Risk of enamel fluorosis is limited to children aged 8 years and below ( 6 years and above, teeth are spared)
Children aged 6 years (posterior teeth can be affected at this period).
By age 6 years, most children can control inadvertent swallowing of fluoride rinses and gel.

67. Measurement of fluorosis: indices
Various indices have been developed to measure dental fluorosis. This includes:
Deans Fluorosis Index(original-1934 and modified-1942)
Thylstrup and Fejerskov index for fluorosis
Fluorosis risk index
Tooth surface index of fluorosis.

68. Deans Fluorosis Index(original-1934 and modified-1942)
Formulated by H. Trendley Dean in 1934
The first Fluorosis Index for categorizing dental fluorosis.
Based on a 7-point ordinal scale: normal, questionable, very mild, mild, moderate, moderately severe, and severe.
Was modified in 1942 in which moderately severe" and "severe" categories were combined.

69. A new 6-point ordinal scale was released and it is extensively used today.
It is also this version that is still recommended by the World Health Organization (WHO) in its basic survey manual (Burt and Eklund, 1999; World Health organization.1997)
Assessment to be done under good sunlight facing the window.

71. Thylstrup and Fejerskov index(TFI) for fluorosis 1978
It is the most sensitive of the indices since it calls for drying which accentuates the appearance of fluorosis

72. Water De-fluoridation
De-fluoridation means to improve the quality of water with high fluoride concentration by adjusting the optimal level in drinking water.
Methods of water defluoridation
Absorption and ion exchange method
Exchange negative ions such OH- group for fluoride ions depends up on PH, temperature, flow rate, grain size of the material.
Commonly used materials: activated alumina, activated bauxite, Zeolite, Tricalcium phosphate, activated bone char, magnesite, magnesite etc

73. Precipitation method:
In a high PH condition, co- precipitation of several elements in water with fluoride ions forms fluoride salts- flocculation
Examples:
Alum
Alum and lime
Lime softening
Calcium chloride
Membrane separation
Reverse osmosis process
Expensive developing countries
30% of raw water is lost in the process
Nalgonda Technique
Invented in India in 1975
Most simple
Least expensive
Easiest to operate
Can be applied at the domestic and community levels
Cost effective
Flexible design to use in different location

75. Conclusion
Fl when used appropriately fluoride is a safe and effective agent that can be used to prevent dental caries.
Appropriate fluoride intake in different population groups in different areas has to be ascertained on the basis of fluoride concentration in food and water resources taken by the local population.

76. References
Fejerskov, J. Ekstrand, Brian. Fluorides in dentistry. 2nd edition.
Mellberg and Ripa. Fluorides in preventive dentistry. 1st edition.
John Murray, Rugg. Fluorides in caries prevention. 3rd edition.
Update on the use of fluoride-S.Joyston-Bechal and E.A.M Kidd
European Academy Of Paediatric Dentistry-guideline on the use of fluoride in children
Lauer WC. Water Fluoridation Principles and Practices. 5th ed. Vol. M4. American Water Works Association
2017 August WACS Update

77. Hussain J and Sharma KC. Environmental Monitoring and Assessment
Hussain J and Sharma KC. Environmental Monitoring and Assessment. March 2010, Volume 162, Issue 1, pp 1-14.
Textbook of community Dentistry, TR Gururaja Rao edition.
Rajan et al 1987,1988, Use of fluoridated toothpaste - Blood fluoride levels in children, International society of fluoride research.
American Academy of pediatric dentistry,1967, revised in Reference manual , Vol 37 No.6.

78. Question The sensitive year for fluorosis is fouth year.
Indication for topical fluoride application.
Concentration of fluorde in Naf, SnF, APF
Is prophylaxis needed before topical fluoride
Content of a dentrifices