SYSTEMIC FLUORIDES

Presented by:Shalakha bhardwaj

Final year

CONTENT 

• INTRODUCTION

• HISTORICAL BACKGROUND

• METABOLISM OF FLUORIDE

• FLUORIDE IN TEETH

• THEORIES OF MODES OF ACTIONS OF FLUORIDE

• FLUORIDE THERAPY

Topical fluorides

Systemic fluorides

• COMMUNITY WATER FLUORIDATION

The saturator system

The dry feeder system

The solution feeder system

Venturi fluoridator system

Saturation suspension cone

• MILK FLUORIDATION

• FLUORIDE TABLETS, DROP, LOZENGES

• TOXICITY OF FLUORIDE

Acute Fluoride Toxicity

Chronic poisoning

• CONCLUSION

• REFERENCES

• Dental caries is a major dental disease affecting a large population of the inhabitants of the world.

• The cariostatic efficiency of fluoride has been convincingly demonstrated and the recent decline in caries prevalence is primarily attributed to the increased use of fluoride agents.

What is fluoride?

• The word fluorine is derived from a Latin word ‘‘fluoro’’ meaning ‘to flow’.

• Fluorine is a member of the halogen family with a relative atomic weight of 19 and an atomic number of 9.

• Freely available in nature, not in its elemental state. Dietary constituents: fish, tea Non-dietary: toothpaste, mouth rinses etc.

• Fluorspar is the principle fluoride containing mineral and the theoretical fluoride content is 49%.

• Fluoride helps to prevent tooth decay, strengthen tooth enamel, and reduce the harmful effects of plaque.

HISTORICAL BACKGROUND

• 1892-The use of fluorides for dental purposes began in the nineteenth century -Sir James Crichton Browne emphasized the importance of fluoride

• 1901-Dr. Frederick McKay highlighted the impact of fluoride in water.

• 1916-McKay and Dr. G.V. Black and mapped the geographical area of the stain 87.5% children in native area with the stain: 9 out of 10 children

• 1939-McKay and Trendly Dean concluded that the incidence of mottled enamel was halted by reducing the level of fluoride in water to1ppm.

• 1902-fluoridens, Copenhagen, Denmark• In the UK : mix with salt –1tsp fluoridensto 2 table sp

salt no effort from user

METABOLISM OF FLUORIDEDIET

DIGESIVE TRACT FAECES

CIRCULATING PLASMA FLUORIDE

PLACENTA & FETUS

MILK

URINE

SOFT TISSUE SWEAT BONE

TEETH

SALIVA

DIGESTIVE JUICE

FLUORIDE IN TEETH 

• Fluoride: identified as one of the elements present in dental hard tissues.

• Fluoride ion is “calcium –seeking”• Apatite: the principal mineral of skeletal tissues.

Crystallized form of calcium phosphate :• Ca10(PO4)6(X)2. If:‘X’ is OH hydroxyl apatite ‘X’ is F Fluorapatite: more

regular

Basic structure of apatite crystal

HPO2-4 F-

F-

PO3-4

Ca2+ HCO-3 Mg2+

HYDROXY APATITE NUCLEUS

Ca10 (PO4)6.(OH)2

LAYER OF ABSORBED WATER,NORMALLY SURROUND THE CRYSAL

THEORIES OF MODES OF ACTIONS OF FLUORIDE

1. Fluoride increased resistance to acid attack: Fluoride were incorporated into tooth structure increased resistance to acid attack. Fluorapatite forms more compact and regular crystals than hydroxyapatite, present less surface area for the action of acids

2. Fluoride influence the solubility rate : Calcium and fluoride ions released from the apatite during initial dissolution forms Calcium Fluoride (CaF2) on the surface of the Fluorapatite hence reducing it solubility.

3. Fluoride catalyses stable apatite phase : Fluoride ions replace carbonate ions in the apatite structure. Apatite crystals with low carbonate contents are more stable and are less soluble compared to those with high carbonate ion content.

4. Fluoride favors remineralization of early carious lesions: Plaque fluid contain fluoride. Enhance re-mineralization of enamel by facilitating the re-precipitation of calcium and phosphate ions into the enamel Fluorapatite.

 

Enamel Plaque Saliva

Demineralization

Ph Bacterial Acids (H+)

pH Salivary Reservoir

Plaque Reservoir (Ca2+, HPO42-, F-)

(Ca2+, HPO42-, F-)

Remineralization

Ca2+

HPO4 2 -

5.Effect on acid production: Fluoride inhibits enolase and ATP-ase activity (Embden-Meyerhof pathway in bacterial metabolism) in oral streptococci hence reduces acid production

6. Fluoride affects the morphology of the teeth making them more self-cleansing : Fluoride administered during tooth formation may result in shallower and wider fissures ,more rounded cusps thus reducing the number and size of sites where food and plaque could accumulate.

FLUORIDE AFFECTING THE MORPHOLOGY OF THE TEETH

Fluoride Therapy

TopicalSystemic fluorides

Topical• Topical fluorides are placed directly on the teeth. some

preparations provide a high concentration of fluoride over a short period of time.

• Other preparation such as dentifiers provide a continuous low concentration of fluoride to the teeth

• Topical fluorides include toothpastes, mouth rinses and professionally applied fluoride therapies.

• They can be either professionally done (in the dental office) or self applied (at home)

DENTIFIERS SELF APPLIED (FLUORIDE GELS) MOUTH RINSE

Systemic fluorides

• Systemic fluorides are those that are ingested into the body and become incorporated into forming tooth structures.

• Systemic fluorides when ingested during tooth development are deposited to some extent throughout the tooth surface.

• fluoride present in saliva, which continually bathes the teeth, provides a constant source that is also incorporated into plaque and facilitates remineralization

 

The different types of systemic fluorides are: 

• Community water fluoridation• Daily fluoride supplements (Rx drops or

tablets)• Bottled water• School water fluoridation• Salt (not in US)• Certain foods

COMMUNITY WATER FLUORIDATION

• Fluoridation is the controlled adjustment of a fluoride compound to a public water supply in order to bring the fluoride concentration up to a level which effectively prevents caries.

• The optimum water fluoride concentration will normally be within the range of 0.5ppm –1.0ppm.”

• Marked reduction of caries when fluoride water levels were at 1-2 ppm.

• Mottling of enamel started to be noticeable at 1.5 ppm.

Optimal fluoride concentration & climatic conditions:

• In temperate regions – 1ppm.

Temp in degree Celsius Recommended ppm

≤18.3 1.1 – 1.3

18.9 -26.6 0.8 – 1.0

≥26.7 0.5 -0.7

Levels of fluoride used:• Irrigation water – 10 mg/l

• Aquatic life - 1.5 mg/l• Industrial water supply – 1.0 mg/l

Before fluoridation, the following factors should be taken into account:

• Daily fluoride concentration of the water supply• Baseline dental caries prevalence• Index of enamel fluorosis and post fluoridation data of the

same population 

Sample collection for fluoride estimation:• 500 ml of water is taken in a clean dry polythene container• 2cc of 6 N HCl is added to inhibit growth/enzymatic change Store at 4 degree Celsius for analysis 

Fluoride concentration can be estimated by:

Fluoride electrode coupled with standard pH meter:• Universally acceptable, quick, simple, economic.• pH meter is used in conjunction with a fluoride electrode &

electrode potentials of the sample is calculated.• Two pH meters are used-Orion901 & Orion 407• Ion meter is one that has inbuilt facility of converting the

electrode potentials into concentration of fluoride in ppm • The unknown concentration of fluoride is calculated by• Typical calibration curve• Applying electrode potential difference by equation• Direct ppm reading.

 Scot- Sanchis method :• Based on reaction between fluoride and red zirconium

alizarine lake.• Fluoride forms a colorless complex ion-ZrF6 & liberates free

alizarine sulphuric acid(yellow)• As the amount of fluoride increases, the color varies from

yellow to red.• Fluoride level is determined by comparing the color with that

of standards.• No longer used.

Choice of equipment & chemical for water fluoridation:

• Should be adapted to local conditions & needs of water network

• Must be efficacious, safe &precise in all climatic conditions• Of standard type-maintenance easily provided.• Choice of distributor should be based on the quantity &

type of fluoride bearing product used• Equipment should have well defined precision limits i.e. not

more than 5 percent error in the • Whole system whatever variation in quantity of water

• It should have a safety mechanism that automatically stops the addition of fluoride if the flow through the treatment plant is suddenly reduced

• Adjustment must be easy and rapid• Apparatus should operate between 20 & 80 percent of total

capacity• In each fluoridation system, an ant siphon mechanism

should be installed in pipes distribute fluoride solution into water, to avoid a concentrated solution of fluoride entering the

system.

Fluoride compounds used in water fluoridation:

A.Fluorspar : mineral containing varying amounts of CaF2B.Sodium fluoride : white, odorless, free flowing material available

either as a powder or a mixture of various crystals expensive source of fluorides

C.Silicofluoride : obtained as by product of purification of phosphate rocks

D.Sodium silicofluoride: Most popular Low cost, cheapest form of fluoride Solutions are corrosive

E. Hydrofluosilic acid : More expensiveF. Ammonium silicofluoride : Produced by neutralising fluosilic acid

with either aqueous ammonia or ammonia in gaseous form

Types of equipment for water fluoridation

The saturator system• Principle : 4 percent solution of sodium fluoride

is produced and injected at the desired concentration at the water distribution source with the aid of a pump

• Factors limiting the utilization : a high hard water level ( total hardness of over 75 mg/l)

• Recommendation : for small town with a total requirement of less than 3.8 million liters/ day

THE SATURATOR SYSTEM

The dry feeder system• Principle : Sodium fluoride or silicofluoride in the

form of powder is introduced into a dissolving basin with the aid of an automatic mechanism

• Factor limiting utilization: the need for care of handling of fluoride, obstruction of pipes, compacting of fluoride while stacked in humid atmosphere.

• Recommendation : in medium sized town- 3.8 -19 million l/day

The dry feeder system

3. The solution feeder system • Principle: Volumetric pump permitting the

addition of a given quantity of hydrofluosilic acid in proportion to amounts of water treated.

• Factors limiting utilization: resistant to attack by hydrofluosilic acid

• Recommendation :in medium and large towns Capacity more than 7.6 million/ day

The solution feeder system 

Venturi fluoridator system:

• Non electrical system developed by J N Leo• Activated by the flow of water in the main water

line and there no possibility of accidental overdosing by surges of fluoride when the main water pump stops

• The tank containing fluoride is made of clear acrylic thermoplastic(plexiglass)

Advantages• Simple to install• Cost is only three-fourths even though same

amount of chemicals are used• Non electrical system• Operator can make visual inspection of the level

of chemicals

Saturation suspension cone• Consists of an upside down cone charged with a bag

of sodium silicofluoride through which a constant flow of water percolates

• The solution is collected at the top by a horizontal perforated plastic pipe which forms the outlet

• A cone 0.91m high and 0.91m in diameter, mounted upside down

• An elevated constant head tank(7-10m head) for feeding water to prepare a constant volume of solution

• A 2cm diameter connecting pipe from the constant head tank to the lower end of the cone

• A surface collector consisting of a horizontal perforated 2.5 cm diameter pipe collects the solution and discharges into a wide mouth funnel which is connected to the pipe

• The cone must be built of a corrosion resistant material such as stainless steel or fiber glass

• The cone is charged with a 45 kg bag of sodium silicofluoride

• The quantity of salt in the cone be never less than 25 kg

 

Technical considerations of water fluoridation:

1.Maintenance and control:

• The fluoridation system must be carefully maintained to ensure maximum efficiency

• Uniform concentration of fluoride ions should be maintained

2.Control at the water treatment plans:• Any difference in the fluoride content of water should be checked• The analysis should be done several times a day

3.Control of the quality of analysis• The responding authority should send three blind samples each

month for analysis at the water treatment plant which should be returned to the responsible authority within 48 hrs

• If any difference known, technical assistance should be sought

4.Control of the quality of water in the network

• Personnel from the water plant should take samples from the network once a week and send them for analysis

• Fluctuations in concentrations should be noted

5.Control of the quality of fluorides used• Each time the delivery of fluorides is received, the

samples should be analyzed to verify whether they correspond to the criteria of quality approved by the responsible authorities.  

Monitoring of fluoridated water

• Hourly check of the weight of the chemical fed into the hopper.

• Calorimetric chemical testing through addition of zirconium alizarin reagent and the results to be compared with the standards

• Less frequent calorimetric testing is advisable(at weekly intervals) upon water at various parts of the distribution system

• Continuous electronic measuring and controlling of fluoride concentration in water

 

Practical aspects of water fluoridation

• There is municipal water supply reaching a reasonable number of homes

• Suitable equipment is available in a treatment plant or pumping station 

• A supply of a suitable fluoride chemical is assured• There are workers in the water treatment plant

able to maintain the system• There is sufficient money available for the initial

installation and running costs• But with increase in dental caries, it is urged that

water fluoridation be considered soon as safe drinking water

Limitations of community water fluoridation

• 50 percent of population in rural areas.• Centralized water distribution system is lacking

Milk fluoridation

• It is the addition of a measured quantity of fluoride too bottled or packaged milk to be drunk by children.

• It was introduced by Ziegler a pediatrician who started the first project with fluoridated milk in Swiss in 1953.

Rationale of milk fluoridation:

• The nutritional value of milk has been well documented.• Milk is often available to children through school and

nutritional program and the use of such distribution system can provide a convenient and cost-efficient method.

• Virtually all form of milk products is suitable for fluoridation and the process is relatively simple.

• Milk fluoridation can be targeted to those communities in greatest need.

• Research has demonstrated the effectiveness of fluoridated milk in preventing dental disease

• The bioavailability of fluoride is not reduced by milk• Fluoridated milk keeps a permanently low level of ionized

fluoride within the oral cavity

• Fluoridated milk may be produced in number of different forms:

• Liquid(pasteurized and sterilized)• Powder

• Sodium fluoride is by far most commonly used agent for large scale production of fluoridated milk. Other agents are calcium fluoride, disodium monofluorophosphate and disodium silicon fluoride

• To calculate the fluoride concentration it is necessary to considered the volume of fluoridated milk consumed daily by each child

• If 200-250 ml of milk consumed daily and the fluoride requirement is 1 mg per day the concentration of fluoride in milk is set at 5ppm.

• Sodium fluoride is generally added to milk in the form of concentrated aqueous solution using a fixed volume ration to obtain the required product usually 1l of solution in 1000l of milk.

• It is best that the solution if sodium fluoride is sterilized at the time of manufacture an d maintain sterile

FLUORIDE TABLETS, DROP, LOZENGES

• Without fluoride in drinking water, a sensible alternative is to give fluoride tablets.

• 2.2 mg NaF contains 1.0 mg fluoride ion. Table shows F ion in relation to age & fluoridation level

Age Water Fluoridation Concentration (ppm) < 0.303 –0.6> 0.6<

0.6< 6 mo - - -

6 mo –3 yrs 0.25 mg - - 3-6 yrs 0.50 mg 0.25 mg -

6-16 yrs1.0 1.0 mg 0.5 mg -

Indications:

• In areas where no central water supplies ,where the fluoride concentration of well water is low and where parental motivation is very high

• As an interim measure in these community with a central water system that have not yet implanted community water fluoridation

• In families where there is a high degree of mobility involving frequent change in the place of work and residence

TOXICITY OF FLUORIDE

Acute Fluoride Toxicity• Results from the accidental ingestion of excessive amounts of

fluoride• Certainly lethal dose (CLD):

• Adult = 5-10 g NaF taken at one time or = 32-64 mg F / Kg body weight

• Children = 2.5 g of NaF -Safety Tolerated Dose (1/4 CLD)• Adult = 1.25-2.5 g NaF or= 8-16 mg F / Kg body weight

• Begin within 30 minutes of ingestion

Clinical features

• GIT: Fluoride in the stomach is acted by hydrochloric acid to form hydrofluoric acid that is irritable to stomach lining, causing:-Nausea, vomiting& diarrhea

• Abdominal pain: Increased salivation & thirst • CVS: Hyperreflexia, convulsions & paresthesia• CVS: Cardiac Failure• Respiratory: Paralysis

Emergency Treatment

• Induce vomiting• Administration of fluoride binding liquid if patients

do not vomit: Milk, Lime• Water gastric lavage• Support respiratory and circulation• Call emergency services and transport to hospital

Chronic poisoning • Applies to long-term ingestion of fluoride in

amounts that exceed the approved therapeutic levels.

• Continued ingestion of high doses of naturally occurring fluoride will be reflected in changes in the teeth.

• Fluorosis of enamel is caused by defective matrix formation (hypoplasia) probably due to direct effect of fluoride on ameloblast metabolism.

• Lesion is usually confined to outer third of the enamel giving opaque white flecks appearance in mild fluorosis

Clinical features of dental fluorosis: • Lusterless, opaque white patch in the enamel

which may become mottled, striated or putted • Mottled area may become stained yellow or

brown• Hypoplastic area may also be present to such an

extent in severe cases that normal tooth form is lost

NORMAL

MODERATE FLUOROSIS

SEVERE FLUOROSIS

Skeletal fluorosis: • Occurs from the ingestion of very high amounts of

fluoride for a long period of time.• Its symptoms are varied in nature:• Severe pain in the back bones, joint and hips,

stiffness in the joint and spine• Outward bending of legs and hands is seen in

advance stages and these part lose their shape and contour

• Pregnant lactating mothers and children are most vulnerable group

• It may lead to blocking and calcification of blood vessels causing cardiac problems

• In it severe form, ‘crippling fluorosis the spine become rigid and joint stiffen

References

• Essentials of preventive and communities dentistry-Soben Peter

• Rahimah Abdul Kadir.(1991)

• Harrison.O., Gracis-Godoy F.(1999). Primary Preventive Dentistry

• Gluck G.M., Morgansteinw.M.(1998). Jong’s Community Dental

Health

• Caldwell R.C.,Stallardr.E.(1977). A Textbook of Preventive Dentistry

• J.J. Murray, A.J. Rugg-Gunn, G.N. Jenkins (1991). Fluorides I Caries

Prevention

THANK YOU