Lecture on toxic effects of fluoride and pathology of dental and skeletal fluorosis.

1. FLUORIDE
TOXICITY

2. Learning Objectives
1. To understand the toxic effects of fluoride.
2. To Enumerate and understand the safe dosage of fluoride
intake
3. To Explain the pathology of dental and skeletal fluorosis.
4. To Understand the Endemicity and recognize Fluorosis as a
public health problem.

3. CONTENTS
Introduction
History
Classification of Fluoride Toxicity
1. Acute Toxicity
* Acute toxic dose
* Manifestations
* Management
2. Chronic Toxicity
* Dental
* Skeletal
* Non- skeletal
Endemicity of Fluoride
Defluoridation
Conclusion

4. FLUORIDE
A DOUBLE EDGED SWORD

5. INTRODUCTION
▪Fluoride is a Double edged sword
▪Inadequate ingestion of fluoride is associated with dental
caries and an excessive intake of fluoride can lead to dental
and skeletal fluorosis.

6. BLESSING
CURSE

7. • During 19th and 20th century, sodium
fluoride was used as a pesticide.
• Many cases of accidental and intentional fluoride
poisoning occurred.
HISTORY

8. Mass poisoning at
Oregon state hospital
▪NaF was mistaken for powdered milk.
▪Appx 17 pounds of NaF was added to 10 gallons of egg.
▪There were 263 cases of acute poisoning and 47 terminated
fatally.

9. Alaska, 1992  150 ppm F in water supply
was present due to
miscalculations.
 Almost 300 people had
nausea,vomiting, abdominal
pain, diarrhoea and One
death.

10. What do you mean by 1 ppm?
Parts per million (ppm)
1 mg of fluoride per liter

11. So How Safe Is Safe?
• W.H.O, 1963 has recommended optimum level of fluoride in drinking water as
0.5 to 1.0 ppm.
• The average daily intake of fluoride from all source recommended for adults is
2.0 to 2.2 mg and in children 5-14 years it is 1.02 mg which leads to plasma levels
of 0.008 to 0.08 ppm.
(Nikiforuk)

12. 10
9
8
7
6
5
4
3
2
FLUOROSIS
0.0 0.5 1.0 2.0 3.0 4.0
DMFT
PPM F IN DRINKING WATER
slight
severe
moderate
mild
POTENTIAL HARM

13. Effect of F ingestion through
fluoridated water at various levels

14. FLUORIDE TOXICITY
1. ACUTE TOXICITY
Excessive ingestion of fluoride over short period of time produce acute toxicity.
2. CHRONIC TOXICITY
Excessive ingestion of fluoride over long period of time produce chronic toxicity.

15. ACUTE TOXICITY
The speed and severity of the response are dependent on the
AMOUNT of fluoride ingested WEIGHT and AGE of the individual.

16. DENTAL PROCEDURES AND FLUORIDE TOXICITY
Most frequently encountered adverse effect of topical fluoride therapy – NAUSEA
Other symptoms
• Abdominal cramps,
• Vomiting
• Diarrhoea
• Increased salivation
• dehydration and thirst
FLUORIDE + H from gastric juices = Hydro Fluoric acid (HF).
STOMACH IRRITANT

17. • Certainly lethal dose (CLD):
Amount of drug likely to cause death.
Adult = 5-10 g NaF taken at one time or 32-64 mg F / Kg body weight
• Safety Tolerated Dose(1/4 CLD)
Maximum dose that can be given without toxicity
Adult = 1.25-2.5 g NaF or 8-16 mg F / Kg body weight
DOSAGE

18. FATALITY
To prevent accidental
poisoning of an infant
weighing as little as 10 Kg,
the council on dental
therapeutics of the American
Dental Association
recommended that no more
than 264 mg of fluoride
(120mg) be dispensed at any
one time.
2-4 Hours after F ingestion fatality can occur if first aid is not administered.
Death – Blocking of normal cellular metabolism
F Ca
F
Ca
F Ca
FCa
F
F
Ca
CARDIAC FAILURE
&
RESPIRATORY
PARALYSIS

19. Treatment
Patient should be transported to the hospital at
the earliest possible time
Should be aimed at reducing the amount of
fluoride available for absorption from GIT
Vomiting should be induced by administering
emetic
If calcium containing solutions are not
available, as much milk as can be ingested
should be given

20. • It is always essential to know the fluoride concentrations in the dental products
by the person who uses them.
• It is also important to know the amounts of fluoride that are contained in the
unit packages, as well as the amounts involved during routine use.
• Many cases of acute toxicity have occurred because of the use of high doses of
fluoride containing dental products, especially by the children.
Remember!!!!

21. Children under 2 years swallow 50% of
toothpaste
5 year olds swallow 25% of toothpaste
Toothpaste = 1 mg F /
gram (1000 ppmF)
1 to 3 grams
“pea” size amount (0.5g) is recommended
for fluorosis susceptible children.

22. FLUOROSIS
Fluorosis is a disease caused by deposition of
fluorides in the hard and soft tissues of the body.
CHRONIC
TOXICITY
SKELETAL
FLUOROSIS
DENTAL
FLUOROSIS
Long term ingestion of small
amounts of fluoride.

23. EFFECT DOSAGES DURATION
Dental Fluorosis > 2 times optimal Until 5 years
Skeletal Fluorosis 10-25 mg/ day 10-20 years
DOSAGE

24. DENTAL
FLUOROSIS
“is a hypoplasia or hypomineralisation of tooth enamel
or dentine produced by the chronic ingestion of
excessive amounts of fluoride during the period
when teeth are developing”

25. CLINICAL FEATURES
• Fluorosis occurs symmetrically between the dental arches.
• The premolar is usually affected
• Followed by second molar, maxillary incisor, canine, first molar and
mandibular incisors.
The severity of the defect appears to be proportional to the total
fluoride consumed.

26. • Fluorosis is usually limited to the permanent dentition
because of the modifying effect of the placenta on
fluoride transfer to the foetus or shorter period of
enamel formation.
• Chances of consumption of large quantities of fluoride
is minimal.
MILK TEETH IS NOT AFFECTED, why?

27. MILD FLUOROSIS
• Ingestion of water with a fluoride concentration of 2 to 3 times greater than the
recommended.
• Causes white flecks and chalky opaque areas on the enamel.

28. SEVERE FLUOROSIS
• Ingestion of water with a fluoride concentration of 4 times greater than the
recommended.
• Brown pitted corroded appearance.
Although these teeth recommend cosmetic problems they are highly resistant to tooth decay.

29. DEAN’S CLASSIFICATION:
• Dean in 1934, has classified dental fluorosis into six categories
according to the severity of condition.
• Examination to be done under good sunlight facing the window.
• He also found that the severity of fluorosis was directly related to
the concentration of fluoride in the water.

31.  Dean’s Index
 Community Fluorosis Index
 Thylstrup and Fejerskov Index (TFI)
 Tooth Surface Index of Fluorosis
 Chronological Fluorosis Assessment Index
FLUORIDE INDICES

32. Management
• Bleaching and enamel micro abrasion techniques are conservative, and provide
highly satisfactory results without excessive wear of sound tooth region.
• Composite resin and resin-modified glass Ionomer are also used for treating
discolored areas.
• Esthetic veneers and prosthetic crowns can be done if needed.

33. • Fluoride is readily incorporated into the crystalline
structure of bone, and will accumulate over time
• Skeletal fluorosis is a bone and joint condition
associated with prolonged exposure to high
concentrations of fluoride
• Fluoride increases bone density and causes changes
in the bone that lead to joint stiffness and pain
SKELETAL
FLUOROSIS

34. • In India, disease first reported by Vishwanathan (1935) to be prevalent in
Madras city.
• Schott identified the disease as fluorosis in Nellore district of Andhra Pradesh.
• At water fluoride levels over 8 ppm, skeletal fluorosis may develop.
HISTORY

35. SYMPTOMS
• Severe pain in the back bones, joints, hips, stiffness in joints and spine.
• Knock –Knee syndrome – outward bending of legs and hands
• F toxic to the foetus if the mother consumes excess fluoride during pregnancy
• Blocking and calcification of blood vessels causing cardiac problems.
• Crippling fluorosis – severe form
• Spine becomes rigid and the joints stiffen – virtually immobilizing the patient.

36. TESTS FOR SKELETAL FLUOROSIS
Affection of the joints can be ascertained through simple tests which can be carried out at the bed-
head side and in the field:
COIN TEST: The subject is
asked to lift a coin from the
floor without bending the
knee.
A fluorotic subject would not
be able to lift the coin without
flexing the large joints of
lower extremity.

37. CHIN TEST: The subject is asked to touch
the anterior wall of the chest with the chin.
If there is pain or stiffness in the neck , it
indicates the presence of fluorosis.
STRETCH TEST: The individual is made to
stretch the arm sideways, fold at elbow and
touch the back of the head. When there is
pain and stiffness, it would not be possible to
reach to the occiput indicating presence of
Fluorosis.

38. Medical Management
▪ Calcium, magnesium, aluminium salts decrease fluoride
absorption and increase excretion
▪ Serpentine, chemically Mg. Metasilicate - absorbs fluorides by
mobilizing it from bones.
▪ Mg. hydroxide has also been found effective

39. Surgical Management
▪Relieves neurological manifestations due to compression
▪Surgical decompression - possible only in early cases, if it is
confined to limited segment
▪Postoperative lung complications may occur later - ventilatory
support is needed
▪Better results are produced cervical and lumbar areas of vertebrae

40. When more than one-fifth (20%) of the persons surveyed in a known high fluoride area
shows positivity of the clinical tests just enumerated, it indicates the Endemicity.
ENDEMICITY

41. • Worldwide in distribution
• Endemic in 22 countries
• Asia and in Asia , India and China are worst affected
• Mexico in North and Argentina in Latin America
• East and North Africa are also endemic
ENDEMICITY

43. DEFLUORIDATION
Although fluorosis once established is irreversible but
it can be prevented through simple interventions.

44. • Precipitation methods are commonly used for
de-fluoridation.
• Lime treatment, routinely used for hardness removal
can remove F particularly when water is having high
Mg hardness.
• Alum is used at domestic level in high doses to remove
the F.

45. NALGONDA TECHNIQUE
▪In India scientists have developed a method known as
Nalgonda technique in which based on the amount of F in
drinking water and alkalinity of the Water (expressed as
mgCaCO3), amount of Alum to be mixed with water is
calculated

46. NALGONDA TECHNIQUE

47. REFERENCES
▪Soben Peter. Essentials of Public Health Dentistry.
5th ed. New Delhi: Arya Publising House; 2013.
▪Hiremath S. S. Textbook of Preventive and Community
Dentistry. (2nd edition). New Delhi:Elsevier; 2011

48. THANK YOU

49. All substances are poisons; there is none that is not a poison.
The right dose differentiates a poison and a remedy.