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Transcript of Fluorides
FLUORIDES
PRESENTED BY: RAHEL CHARIKAR
Dental diseases – most prevalent chronic diseases
Western industrialized countries – decline in dental caries – responsible factors – changes in sugar consumption ,improved oral hygiene ,and use of fluorides through systemic and topical routes including fluorides in tooth paste ,fluoride in mouth rinsing ,and other school based preventive programs.
Developing countries – increase in dental caries – responsible factors – urbanization ,rural immigrants adopting the behavior of modern society and changing their traditional dietary habits with less use of fluorides and virtually few or no preventive programs.
Fluorides is a double edged sword????
Coz at optimal level- not only decreases the incidence of dental caries but is also necessary for maintaining the integrity of oral tissues
at the same time at higher levels that too if taken excess during the developmental stages can cause adverse effects like dental fluorosis and skeletal fluorosis.
1934 – Dean developed a standard system for classification of dental fluorosis the `mottling index `. (Deans index for fluorosis).
1942 – Dean et al discovered that at 1ppm F in drinking water ,a 60 % reduction in caries experience was observed.
1945 – worlds first artificial fluoridation plant was started at Grand Rapids,U.S.A.
1969 – WHO advocated that 1ppm of fluoride in community water supplies was a practical and effective public health measure.
Estimated daily intake of fluoride Average daily intake of fluoride from dry
food substance is in the range of 0.2 to 1.8 mg and the average daily intake from water containing 1ppm fluoride is about 1.5 mg ,the total daily intake for adults being in the 1.7-3.3 mg range.
The total fluoride intake in children is about 0.7 mg/day for the younger ,bottle fed group of children and about 1.3 mg fluoride/day for the 12 year old group.
99% of all the fluoride in the human body is found in calcified tissues
Accretion: process where most of the fluoride is buried within the mineral crystallites during the period of crystal growth.
Amt. of fluoride in the outer enamel: 2200-3200 ppm.
Amt of fluoride in cementum: 45oo ppm.
Amt of fluoride in cementum is higher than that of any skeletal or dental tissue.
Fluoride and Dental PlaqueFluoride content ranges from 15-64 ppmIonic fluoride activity is between 0.08
and 0.8 ppm- too low to inhibit metabolism of plaque bacteria.
Plaque fluoride originates from prolonged day to day contact with the low levels of fluoride in the saliva and gingival fluid
FIRMLY BOUND FLUORIDE IN PLAQUE IS MORE STABLE THAN FLUORHYDROXYAPATITE
When plaque is exposed to high conc. Of fluoride, calcium fluoride is formed.
Chief organ of excretion of fluoride is kidney.
Renal clearance rate: 30-50 ml/minFluoride analysis: 1. Ionic fluoride: isotachophoresis and ion
chromatography2. Bound fluoride: distillation, wet and dry
ashing, acid extraction Fluoride analysis in food:1. Water and beverages: potentiometric
measurements with aid of fluoride ion specific electrode
2. Foods: micro diffusion technique described by Taves.
Mechanism of action of fluorides1. Increases enamel resistance or
Reduction in enamel solubility:
Hydroxyapatite (less soluble in acid)
Fluor apatite (least soluble in acid)
Newly erupted tooth
Matured tooth
Matured tooth with fluoride
Mechanism of action of fluoridesIncreases enamel resistance/improving
crystallinity: hydroxyapatite crystals are small and contain
several impurities. Fluorine ion even in low concentrations increases crystallinity of hydroxyapatite . This is based on “void theory”
void theory: association of hydroxyl ions with calcium ions in unit cell.
fluoride ions replace the occasional voids and replace missing hydroxyl ions-effectively stabilize crystal structure by providing stronger hydrogen bonds
2. Remineralization of incipient lesions….
Plaque bacteria
Fermentable carbohydrates(sucrose)
Organic acids
White spot lesions
remineralisation demineralization
remineralisation
FluorideGood oral hygiene
practicesChange in sugar
consumption
3. Fluoride and oral bacteria: saliva is source of fluoride. Topical application of fluoride increases
salivary fluoride levels more than ingested fluoride.
Affects microorganisms in several ways: low conc.-inhibits acid formation
higher conc.-affects growth and metabolism even higher conc.-bactericidal Fluoride acts on enolase enzyme and
prevents conversion of glucose to lactic acid Prevents entry of glucose into bacterial cell Prevents conversion of glucose to glycogen
which acts as storehouse when glucose is absent…
4. Increased rate of post eruptive maturation: Newly erupted teeth have hypo mineralized
areas that are prone to dental caries Fluoride increases rate of mineralization, or
post eruptive maturation Organic material deposited on enamel
surface further increases its resistance to dental caries
5. Modification in tooth morphology: Fluoride action on tooth morphology is
entirely by systemic route. Shallow occlusal grooves, lower cuspal
height and smaller size teeth.
Classification of fluoride therapy1. Systemic fluoridesa. Community water fluoridationb. Salt fluoridationc. School water fluoridationd. Milk fluoridatione. Fluoride supplements
2. Topical fluoridesi. Professionally appliedii. Sodium fluoride preparationiii. Stannous fluoride preparationiv. Acidulated phosphate fluoridev. Fluoride varnishvi. Fluoride impregnated floss and prophylactic pastevii. Fluoride containing dental materials and devicesb. Self-appliedi. Fluoridated dentifriceii. Fluoridated mouth rinse
Community water fluoridationWater fluoridation is defined as the
upward adjustment of the concentration of fluoride ion in public water supply in such a way that concentration of fluoride ion in the water may be consistently maintained at 1 parts per million by weight
Climate is hot-maintain slightly less than 1 ppm to compensate for excess consumption of water during summer. In winter conc. is increased to compensate for lesser water consumption
Chemicals used for fluoridation1. Sodium fluoride(powder): most
expensive source2. Sodium silicofluoride(powder):
corrosive in nature3. Hydroxyfluorosilicic acid4. Fluorspar5. Ammonium silicofluoride: Types of equipment used:1. Saturator system2. Dry-feeder system3. Solution-feeder system
Limitations of community water fluoridationCentralized piped water
distribution is crucial requirement for community water fluoridation
Lacking in most developing countries
introduction requires support of top health authorities and of the government in the form of laws, decrees, regulations and budget allocations.
Salt Fluoridation Is the controlled addition of fluoride, usually sodium
or potassium fluoride, during the manufacture of salt for human consumption.
Introduced by Wespi in Switzerland in 1955Recommended concentration is 250 mg of
fluoride/kg saltMethods of addition of fluoride in salt:1. Batch processing: fixed amt of fluoride compound
added to fixed amt of refined salt. sodium fluoride is used as it is much cheaper.2. Continuous processing: spray concentrated
solution of fluoride through a nozzle onto the salt passing on conveyor belt.
potassium fluoride is preferred because of its high solubility in water.
• Advantages: Economical: as does not require community
water supply. Caries reduction:40-50% Permits individuals to accept or reject it• Limitations: Consumption of salt negligible till age of 4-
5yrs, so its of no use in smaller children Not useful in medically compromised patients Amt of fluoridated salt ingested may decrease
with increasing consumption of processed foods if processors do not use fluoridated salt.
Requires modern technology and high level of technical expertise
School water fluoridationSuitable alternative in communities with no central
water supplyReduces dental caries by 40%Primary effects are systemic and also topical
effectsRecommended concentration-4.5 ppmReasons for recommending high concentration:1. Students receive only small part of the daily
intake of water when they are in school2. Students may not attend the school throughout
the year3. Frequency of drinking water in school by children
is variable4. Children attend school for only couple of hours
Advantages: 1. target population is school
children2. Caries experience is high during
developmental period3. Quite economicalLimitations:1. Need for co-operation from
school authorities2. All children may not attend the
school all days
Milk fluoridation Is the addition of a measured quantity of fluoride to
bottled or packaged milk to be drunk by children Rationale of milk fluoridation:1. Nutritional value of milk is well documented2. Milk is available to children through school and
nutritional programs and the use of such distribution systems provide convenient and cost efficient vehicle.
3. All forms of milk are suitable for fluoridation and process relatively simple
4. Can be targeted to communities in greatest needs5. Bioavailability of fluoride is not reduced by milk6. Fluoridated milk keeps permanently low level of ionized
fluoride within the oral cavity, promoting remineralisation
7. Dual mode of action: topical and systemic8. Preventive effect was greater if consumption was earlier
in the child’s life.
1st project began in the Swiss city Winterthur in 1955.
Concentration is 2.2mg of sodium fluoride added to 1/4th liter of milk.
Limitations:1. Since children from lower
socioeconomic groups tend to drink less amount of milk or no milk at all, hence they would be benefited least.
2. Costly3. Parent co-operation necessary4. Any benefits cease, as an individual
grows older and drinks less amount of milk.
Fluoride tablets/drops/lozengesAlternate source of systemic fluorideIt is given in the form of fluoride tablets,
fluoride drops and lozengesCariostatic effect ranges from 30-70%Fluoride supplements are taken on daily basis
from 6months to 14 years of ageHave fluoride content of 1,0.5 or 0.25 mgOriginally made as fluoride pills to be
dissolved in a little of the infant’s drinking water. Later chewable tablets and lozenges are manufactured for older children, to be chewed or sucked for a minute or two before swallowing. Intention is to get both systemic and topical effects.
Most tablets contain neutral NaF.Factors to be considered for the
correct dosage are:i. Age of childii. Existing fluoride concentration
in the water supplyiii. Climatic conditions Trade names are Fluoriday,
Tymafluor, Luride
Topical fluoridesTopically applied fluorides are
used to describe those delivery systems which provide fluoride for a local chemical reaction to exposed surfaces of the erupted dentition.
Delivery systems include: prophylactic pastes, solutions, gels and varnishes, fluoride dentifrices and rinses.
Indications for topical fluoride use,1. Caries active individuals2. Children shortly after periods of tooth
eruption3. On medications that reduce salivary flow,
or have received radiation to head and neck.
4. After periodontal surgery when roots of teeth have been exposed
5. Patients with fixed or removable prosthesis and after placement or replacement of restorations
6. Mentally and physically challenged individuals
Topical fluoride products divided into 2 broad categories:
1. Professionally applied products: high fluoride concentration products, ranging from 5000 and 19000 ppm, which is equivalent to 5-19 F/ml.
2. Self applied products: low fluoride concentration products ranging from 200 to 1000 ppm or 0.2-1 mg fluoride/ml.
Professionally applied topical fluorides The fluoride vehicles used are:1. Aqueous solutions and gels- Gel adheres to tooth for
considerable amount of time When trays are used, it is
possible to treat two or four quadrants simultaneously
Available as sodium fluoride, stannous fluoride, acidulated phosphate fluoride
2. Fluoridated prophylactic pastes- Surface enamel contains higher
levels of fluoride than internal layers.
Prophylaxis if performed removes the fluoride rich layer
If prophylaxis pastes containing fluorides are used, then the lost fluoride is replenished with added small net gain in the concentration
3. Foam Developed so as to minimize the risk of
fluoride over dosage as well as to maintain the efficacy of topical fluoride treatment.
Much lighter than conventional gel so only small amount of agent is needed for topical application
Surfactant in foaming agent has cleansing action by lowering the surface tension
APF foam does not require suctioning, it offers advantages for home use as well as for treatment of young children and disabled persons where saliva evacuation is not feasible
4. Fluoride varnish Fluoride compound is incorporated
directly into varnish like coating material.
This increases the time of contact between the enamel surface and topical fluoride agents
5. Duraphat First fluoride varnish Viscous yellowish material, containing
22,600 ppm fluoride as sodium fluoride in a neutral colophonium base
6. Fluorprotector Clear polyurethane based
product containing 7000 ppm fluoride from an organic compound , difluorosilane
7. Carex Fluoride varnish 1.8% fluoride
Agents used for topical application are:1. Neutral sodium fluoride First fluoride compound to be used for topical
application Minimum of four applications with 2% sodium
fluoride Advantages: relatively stable, no need to prepare fresh
solution for each patient Taste well accepted by patients Solution is non-irritating to the gingiva It does not cause discoloration of tooth
structure Applied in age range 3 to 13 rather at annual
or semiannual intervals. Disadvantages: Patient has to make four visits to the dentist
within a relatively short period of time
Method of application- Knutson’s technique(four appointments)
At initial appointment, teeth cleaned with aqueous pumice slurry-isolated with cotton rolls-dried with compressed air. Teeth isolated by quadrant or half mouth.
Using cotton tipped applicator sticks,2% sodium fluoride solution is painted on air dried teeth. Solution is allowed to dry for 3 to 4 mins
Procedure repeated for each isolated segments until all teeth are treated
Second, third and fourth fluoride application scheduled at intervals of one week each
Four visits recommended at ages 3,7,11,13 coinciding with eruption of different groups of primary and permanent teeth
2. Stannous fluoride Most commonly used is 8% stannous
fluoride preparation Technique of application(Muhler’s technique) Each tooth surface cleaned with pumice or
other dental cleaning agent for 5 to 10 seconds
Unwaxed dental floss passed between the interproximal areas. Waxed floss may coat the tooth surface and adversely affect fluoride uptake.
Teeth isolated and dried with air. Stannous fluoride is applied using the paint-
on technique and solution kept for 4 mins. Repeat applications made every 6 months
Advantages: 6 months recall conforms to the practicing
dentist’s usual patient-recall system Administrative difficulties, particularly in public
health programs created by need to arrange four appointments is avoided
Disadvantages: In aqueous solution, material is not stable Application is unpleasant as 8% solution is quite
astringent and disagreeable in taste Solution occasionally causes a reversible tissue
irritation manifested by gingival blanching Occasionally causes pigmentation of teeth.
Staining usually appears in association with carious lesions, hypo calcified regions and around margins of restorations.
3. Acidulated phosphate fluoride Method of application Oral prophylaxis Isolation APF solution applied
continuously and teeth are kept moist for 4 mins
Semiannual or annual application
In case of gel application, disposable trays of various sizes are used
Advantages: Requires only 2 applications in a year Gel preparation can be self applied Has ability to deposit fluoride in enamel to
deeper depth than neutral sodium fluoride or stannous fluoride
APF is stable
Disadvantages: Keeping teeth wet for 4 mins Acidic, sour and bitter in taste Cannot be stored in glass containers Repeated or prolonged exposure of porcelain or
composite restorations to APF can result in loss of materials, surface roughening and possible cosmetic changes
Self Applied Topical fluorides1. Dentifrices: Fluoride compounds used in dentifrices are: Sodium fluoride Stannous fluoride: not used as it causes
staining of teeth, pigmentation of hypo plastic areas and margins of restorations. Also has metallic, astringent taste.
Monofluorophosphate Amine fluoride dentifrice: markedly superior
properties as compared to sodium fluoride and monofluorophosphate alone or in combination
Adverse effects of dentifrices are: Single brushing with full ribbon of
paste will expose individual to approx. 1 mg F. risk of children under 6 yrs of age developing dental fluorosis from regular ingestions of large amounts.
Detergents and flavoring oils irritate stomach when ingested in large amounts and cause vomiting.
Abrasives may interfere with complete intestinal absorption of fluoride from toothpastes.
2. Fluoride mouthrinsesSodium fluoride mouthrinses: Formulated at conc. of either 0.2% for
weekly use or 0.05% for daily use.Rinses are intended to be used by
forcefully swishing 10ml of the liquid around the mouth for 60 seconds before expectorating it.
Other mouthrinses used are stannous fluoride rinses, amine fluoride rinses and ammonium fluoride rinses.
Recommendations for fluoride mouthrinses:
Rinse and expectorate technique can be used for patients in fluoride deficient communities
Swish and swallow technique employed when conc. of fluoride in drinking water is 0.3 ppm or lesser.
Beneficial for patients with increased caries risk.
3. Fluoride gels Include neutral sodium fluoride and acidulated
phosphate fluoride with a fluoride conc. of 5000 ppm and stannous fluoride which has conc. of 1000 ppm
Either applied on trays or brushed on teethApplied once a day or morePatient’s brush their teeth for 1 min with the gel or if
trays are used several drops are placed in each tray and held in contact with the teeth for 5 mins.
Limitations are: Deliver high conc. of fluoride on tooth surface at
regular intervals and this causes deposition of calcium fluoride
Present toxicity hazard Tedious to use on daily basis over a long period of
time
DefluoridationDefined as downward
displacement of level of fluoride in drinking water to optimal level of 1 ppm
Methods used are of two types:i. Based upon ion exchange
process or adsorptionii. Based on addition of chemicals
to water during treatment.
Ion exchange resinsAre commercially produced
resins which are expensive and uneconomical in most circumstances
a. Carbionb. Defluoron 1c. Defluoron 2
Nalgonda techniqueEquipment: FC/RCC setting tank, flash mix and
pump, flocculator, rapid gravity sand filter and disinfection unit
Raw materials: high fluoride raw water, alum, lime and bleaching powder
Procedure: container of 20-50 liters- adequate amt of lime water(30 mg/liter of water) and bleaching powder are added to water, first and mixed well with it- alum solution then poured and water stirred for 10 mins- Later contents stirred for 1 hr and followed by flocculation, sedimentation and filtration- water allowed to settle down for 1 hr- clear water drawn through filtration without disturbing the sediment.
Acute Fluoride ToxicityOccurs when dose of fluoride intake starts from
32-64 mg/kg of body weight in one single retained dose. Safely tolerated dose is 8-16 mg of fluoride per kg body weight
Management: History Physical signs: nausea, abdominal cramps,
vomiting, diarrhea, increased salivation and dehydration and thirst.
Emergency care: provide cardiac monitoring, hypocalcaemia may be detected, perform gastric aspiration and lavage within 1 hr of ingestion, administer milk, calcium carbonate and aluminum and magnesium based antacids to bind fluoride, correct calcium deficiency with IV calcium chloride
Dental FluorosisIs a hypoplasia or hypomineralisation of
tooth enamel or dentine, produced by chronic ingestion of excessive amounts of fluoride during the period when teeth are developing
Characterized by lusterless, opaque, white patches in the enamel which may become mottled, stained, pitted
Major cause is consumption of water containing high levels of fluoride by infants and children during first 6 years of life.
Skeletal fluorosis Occurs from ingestion of very high amounts of
fluorides for long periods of timeSevere pain in backbone, hips, joints, hips,
stiffness in joints and spineOutward bending of legs and hands seen in
advanced stages. Called knock knee syndromeCan also damage fetus if mother consumes
excess fluoride during pregnancyBlocking and calcification of blood vessels
causing cardiac problemsSeverest form-crippling fluorosis-spine
becomes rigid and joints stiffen, virtually immobilizing the patient
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