objectives
At the end of the lecture student should know
• Explain what is fluoride and its sources.
• Explain metabolism of fluoride
 Absorption
 Distribution
 Excretion
• Discuss mechanism of action of fluorides
• Fluoride delivery methods
 Topical fluorides
 Systemic fluorides
• Discuss toxicity of fluorides.
INTRODUCTION
SOURCES
FLUORIDE METABOLISM
HISTORY
MECH OF ACTION
CLINICAL USE OF FLUORIDES
SYSTEMIC FLUORIDES
TOPICAL FLUORIDES
FLUORIDE TOXICITY
Introduction
• Dental caries is a major dental disease affecting a large
population. It affects quality of life causing pain and
discomfort.
• Scientific research, technologic advances and understanding
of the disease process have brought the back the art of
preventive science.
• The cariostatic effect of fluoride has demonstrated the decline
in the prevalence of dental caries.
Latin word FLUORE- to flow
Halogen family, Most electro negative
Atomic No 9
Atomic Weight 19
1. Fluorides in ATMOSPHERE:
•
•
Volcanic eruptions…
•
Soil and water particles…..
Rain, deposition of dust, Snow, and Fog…..
•
Industrial wastes…. (Coal burning,
Power generation plants, Aluminium factory,
Phosphate fertilizers, Phosphoric acid
and Manf of glass, ceramic and bricks)
2. Fluorides in LITHOSPHERE:
•
•
•
•
•
•
•
Siliceous igneous rocks
Alkalic rocks in geothermal waters and
hot springs
Volcanic gases and Fumarole
Widely distributed in earth crust
Averages about 300ppm
Constitutes about 0.087% of its weight
3) Fluorides in BIOSHPERE:
• Plants – 2-20mg/g of dry wt
• Leafy vegetables 11-26mg/g of dry wt
• Plants grown with acidic soil…..
• Some plants accumulate higher conc. of fluoride
–tea plants
• Animals……..10-20ppm
• Fish: sardines, salmon, mackerel –20ppm
4) Fluoride in HYDROSPHERE:
• All waters contains fluoride due to universal
presence in earth’s crust
• Rain waters, lakes and wells
• Sea water: 0.5-1.4mg/L
• River water: 0.5mg/L
Others include:
Drugs of osteoporosis and related metabolic skeletal disorders
Fluoridated corticosteroids
Anesthetic solutions
Chewing gums
Dentifrices
Daily: Adult;2.2-3.2ppm, Child;1-1.2ppm
absorbed through stomach, lungs and intestine.
Through urine, sweat and feaces
1901 Dr Fredrick McKay
COLORADO STAINS
MOTTLED ENAMEL
-Characterized by ” Minute white flecks or Yellow or brown
spots or areas scattered irregularly
1905- St- Louis
1908- Colorado, presented paper
1909- Dr Greene Vardiman Black
Dean of Northwestern University Dental School, CHICAGO
Conducted microscopic examination.
Dr. G V Black’s histological findings regarding this was published in
the paper “ an endemic imperfection of the enamel of the teeth
heretofore unknown in the literature of dentistry”
In 1912- article of Dr James Eager (1902)
In residents of NAPLES, called this as “Denti di chiaie”
In 1916 McKay with Dr G V black conducted studies in 26
different Communities in various parts of USA (6873)
Concluded that there was something unidentified factor
that was responsible for Mottling of enamel
They ESTABLISHED their assumption when they came
across similar enamel mottling in residents of BRITTON
Water source changed from shallow to deep wells after 1898,
Prior to 1898 – no mottling seen
And born after 1898 had mottling of enamel
They assumed that there is something in the water that
was responsible for this
Similar results in studies of BAUXITE, In 1909 they changed
their water supply From shallow to deep wells
In 1931 Churchill H V , Chemist , Aluminium Corporation Of America,
New Kensington, Pennsylvania
Bauxite water had fluoride of Conc =13.7ppm
Dr Trendley H Dean in 1931
1931- conducted ‘SHOE LEATHER SURVEY’
1934- Trendley H Dean introduced mottling index, know as
Dean’s Fluorosis Index
In 1942 mile stone discovery that 1ppm of fluoride reduced 60%
of dental caries was observed
1) Increased enamel resistance
or Reduction in enamel solubility
2) Increased rate of post eruptive maturation
3) Remineralisation of incipient carious lesion
4) Fluoride as inhibitor of demineralization
5) Interference with microorganisms
6) Modification of tooth morphology
Systemic
•Community Water Fluoridation
•School Water Fluoridation
•Dietary Supplements
•Salt Fluoridation
•Milk Fluoridation
•Fluoride Drops
Topical
• Professionally applied
• Self applied
TOPICAL FLUORIDES
PROFESSIONAL
•Knutson’s Technique
•Muhler’s Technique
•APF Solu /Gels
•Amine Fluoride
•Varnish
•Others,
SELF APPLIED
•Dentifrices
•Mouth Washes
•Fluoride Gels
Results of one the studies by RICHARD et al shows that:
OPTIMAL FLUORIDE CONC.= 0.7 – 1.2 ppm
NOW 0.5 – 1.0 ppm
CARIES REDUCTION IS 60 -65 %
School Water Fluoridation
Used in case of ……………………
Recommended Conc. 4.5 – 6.3 ppm
40 – 50 % reduction in DMFT scores
MILK FLUORIDATION
Started in SWITZERLAND in 1953 by Zeigler a pediatrician
Sodium fluoride is usually added to milk in the form of
concentrated aqueous solution.
Amount 1 liter to 1000 liters of milk.
SALT FLUORIDATION
SWITZERLAND since 1959
By 1967, three quarter of domestic salt sold in switzerland. Was
fluoridated at 90mg/kg salt(90ppm)
Later it was raised to 200, 250, & 350 mg/kg salt
Advantage:
-Safe
-No supervised water works nor water
distribution systems are necessary
-low cost
Disadvantage: No control over individual consumption
FLUORIDE TABLETS & VITAMINS
FLUORIDE DROPS
Both are available by the
prescriptions given by
dentist or pediatrician and
not available over the
counter.
Professionally applied Topical Fluorides
Knutsons technique
• First the teeth are cleaned, isolated and dried with compressed air.
• Using cotton tipped applicator sticks, the 2% sodium fluoride
solution is painted on the air dried teeth so that are surfaces
become wet, solution should be allowed to dry for 3 – 4 minutes.
• A second, third and fourth fluoride application is done at the
interval of approximately one week.
• The four visit procedure is recommended for the ages 3, 7, 11 and
13 years.
APF (Acidulated Phosphate Fluoride) gel application
• First oral prophylaxis is done and the patient should sit in an upright
position, the teeth should be isolated and air dried.
• Application of APF gel should be done using trays which fit patients
upper and lower dental arched, a disposable foam lined tray is
preferred.
• Approximately not more than 5ml of gel is poured in the tray and
the tray is placed inside the patient mouth for about 4 minutes,
saliva injectors should be used during the procedure.
• After 4 mins the patient is asked to expectorate and instructed not
to eat, drink or rinse for at least 30 mins.
• The procedure is recommended at 6 – 12 months interval.
TOXICITY OF FLUORIDES
• Toxicity of fluorides can be classified as acute toxicity & Chronic
toxicity.
• Acute toxicity results from rapid excessive ingestion of fluoride at one
time.
• e.g. Fluoride tablets, gels, & mouth rinses.
• Generally serious symptoms develop within one or two hrs after
ingestion & death occurs from 2-4 hrs after ingestion.
• The certainly lethal dose is 32-64 mg/Kg body weight & safely
tolerated dose is 8-16 mg/Kg body weight.
SIGNS AND SYMPTOMS OF ACUTE FLUORIDE
TOXICITY:
GIT: Nausea, vomiting, diarrhea,
abdominal pain and cramps.
Neurological: Paresthesia, paresis, tetany,
CNS depression & coma.
Cardiovascular system: Weak pulse, hypertension,
pallor, cardiac irregularities &
ultimately failure.
Blood chemistry: hypocalcemic acidosis,
hypomagnesemia.
CHRONIC FLUORIDE TOXICITY:
• Chronic fluoride toxicity though uncommon results from
long term ingestion of small amounts of fluoride.
e.g. Aluminum production, Magnesium foundries,
Fluorspar processing & super Phosphate manufacture.
Concentration
Effects
2ppm or more
mottled enamel
8ppm
10% osteosclerosis
20-80 mg / day
crippling fluorosis
50ppm
thyroid changes
100ppm
growth retardation
More than 125ppm
kidney changes
2.5-5 gm
death
Clinical features of
Fluorosis
0.7- 0.8 ppm
1.5 ppm
1.2 ppm
2.0 ppm
3.0ppm
5- 6 ppm
3.0ppm
5- 6 ppm
> 7.0 ppm