Topical protection of teeth

Topical protection of teeth

Fluoride

By

Mohamed G. Aboelsaud

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Topical tooth protectionAll measures to maintain an intact outer surface for the tooth through treatment of that surface itself.3

Traditional measuresOperative dentistry:- caries control (traditional 6m recall).

Prophylactic odontomy:- as soon as possible after eruption.

Fissure eradication:- deep fissures are opened to wide cleansable grooves.

Prophylactic fissure filling:- = (prophylactic odontomy).

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Pit and fissure sealant:- Preventive resin restoration (PRR):- topical chemotherapy:- increase resistance of the exposed surface of the tooth ammoniacal silver nitrate

Topical Fluoride application:- Remineralization:- (ACP) (tetra calcium phosphate and dicalcium phosphate anhydrate). Polymeric coatings:- thin polymeric coating

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Laser light:- (reducing the rate of demineralization, sealing pits and fissures, increase F uptake, vaporizes caries and fuses sound enamel, improve sealant retention.

Augmenting host resistance:- Recombinant DNA technologies, small peptides to enhance saliva functions. 6

We can categorize those measures mentioned into:-

7Biological measuresPhysical measuresChemical measuresMechanical measuresPolymeric coatingsLaser lightammoniacal silver nitrateOperative dentistryTopical Fluoride applicationProphylactic odontomy

Augmenting host resistanceACPFissure eradication

tetra calcium phosphateProphylactic fissure filling

dicalcium phosphate anhydratePit and fissure sealant

Fluoride Introduction (element fluoride)HistorySource of fluorideMetabolismMechanism of actionDelivery methodstoxicity

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In elemental state is a pale yellow green gas

A member of halogen family. The most reactive member

11 As essential nutrient.

12one of the 14 physiologically essential trace elements required for the normal growth and development.

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1901

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Colorado stain

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mottled enamel

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An endemic imperfection of the enamel of the teeth heretofore unknown in the literatures of dentistry".

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This assumption established when this condition observed in Britton residents when changed water supply from shallow wells to deep wells after 1898, people born before that had normal appearance.

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1931, H. Dean High concentration of fluoride in water is directly related to the severity of enamel mottling.Enamel mottling was widespread in areas with water having fluoride content of 3 ppm.Mottling with discrete pitting of enamel was notice at fluoride of 4 ppm.Mottling was less in case f fluoride levels of 2.5:3 ppm with dull chalky white appearances of teeth.No mottling or any other enamel changes were observed inn areas with water with 1 ppm fluoride concentration.

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Term (mottled enamel) gave away to more exact term (dental fluorosis).

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1942.The important milestone discovery was made by Dean et al that 1 ppm fluoride in drinking water obtain 60% reduction in caries experience22

1945.The world's first artificial fluoridation plan was started at Grand Rapids U.S.A.

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1969.

24that 1 ppm fluoride in water was practical and effective public health measure.

** Sources of fluoride

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Dried tea leaves contain 100:400 ppm depending on the brand.F is rapidly released into tea fusion most of it within 5:10 min. (ingestion of F by tea drinkers is in the range from 0.04 to 2.7mg/day.

Water, naturally or artificially fluoridated, is the most important single source of fluoride.

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absorption1 liter of fluoridated water containing 1 ppm F consumed. 1/3 : 1/2 of F in food is assimilated31

Passive transportation32

Solubility and degree of ionization of the compounds. (rate of absorption is inversely related to gastric acidity).

Other dietary constituents such as Ca which may form insoluble salts with F.

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Blood plasma is considered the central compartment into which fluoride must pass for its subsequent distribution and elimination.

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Fluoride metabolism

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F in plasma exists in:-*ionic "free" F. *non-ionic "bounded" F.Ionic F is the public health importance.

Fluoride concentration in plasma in healthy fasting person consuming 1ppm F, is 1M "0.019 ppm" which increases with age.

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**pharmacokinetics**

Initial increase: - absorption phase till plasma peak is reached 1M "0.019ppm" absorption decreases.

Rapid fall for 1hr:- distribution phase phase from blood to tissues.

Slow decline: - elimination phase phase, this decline reflects the plasma half-life of F "4 : 10 hrs.".

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F is a mineralized tissue seeker. Approximately 99% of all F in the human body found in calcified tissues.

accretion: - where most of fluoride is buried within the mineral crystallites during the period of crystal growth.

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F in saliva

-From salivary glands "very low" 0.007: 0.05 ppm.-From fluoride containing materials.

** 10mg F will raise parotid gland F levels from 0.02 ppm to 0.28 ppm.

** 5min after APF treatment, saliva F will be approximately 100 ppm.

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F in pulp 100: 650 ppm.

F in dentin--- 200: 300 ppm

F in cementum --- 4.500 ppm

Concentration of fluoride in cementum is higher than that of any skeletal or dental tissues.

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F in enamel** Outer enamel containing F levels between 2.200: 3.200 ppm

** Acquisition of F by the enamel surface appears to continue at a perceptible rate as long as the tissue remains porous.

** F interferes with the process of maturation, thus prolonging the length of time during which the enamel is porous and therefore will extend the period of rapid fluoride uptake.

** Fully mineralized enamel has a density of 2.98 gm/ml with a porosity as low as 0.1% space by volume.

** Creation of porosity or destruction of the apatite lattice is necessary to increase the concentration and depth intake, by high level F "1.000: 10.000 ppm" &/or acidification.

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F in plaque---15: 65 ppmThe ionic F activity of neutral plaque is between 0.08: 0.8 ppm and it is too low to inhibit the metabolism of plaque bacteria.

**Plaque F acts as a reservoir for the ionized form, "As the pH drops and favors remineralization and bacterial inhibition."

** When plaque is exposed to high concentration of F, CaF is formed, slightly soluble in water, in buffers and in 0.5M perchloric acid and complete dissolved in strong mineral acids.

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Mechanism of action of fluoride

The exact mechanism of action is not completely understood.Increase enamel resistance "reduce enamel solubility" by formation of fluorapatite which is less soluble.Increase rate of post-eruptive maturation, increase rate of mineralization of hypo mineralized areas.Remineralization of incipient lesions, growth of crystals which become larger than those in either demineralized or sound enamel.The composition of remineralized enamel is different from normal enamel and may vary according to conditions employed to produce the remineralization.

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"F pH effect"

5-Interference with micro-organisms,high concentration of F is bactericidal.low concentration of F is bacteriostatic.Fluoride lodges in plaque and inhibits bacterial enzymes that responsible for acid metabolism. enolase, bacterial phosphatases and cation transport47

6-Modification of the tooth morphology. During tooth development, fluoride makes the morphology of teeth with more rounded and smaller cusps with shallow fissures and grooves.

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Topical fluoride compounds used in preventive dentistry.

Neutral sodium fluoride :- NaF 2%

20 g of NaF dissolved in 1000 ml of distilled water.

Stored in plastic containers, F reacts with glass t form SiF which reduce the availability of free active F.

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Method of application "knutsons technique"

Treatments are given in a series of four appointments.

Initial appointment, prophylaxis by aqueous pumice and isolation with cotton roll, then dry with air.Cotton applicator is used t paint the dried teeth till all surfaces are visibly wet, and then the solution is allowed to dry for 3 to 4 mins.

At 2nd, 3rd and 4th visits the procedure isn't preceded by prophylaxis and is scheduled with intervals of one week.

The four visits technique is recommended for ages 3, 7, 11 and 13 years old.

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Mechanism of action Sodium fluoride

reacts form with hydroxyapatite crystals to form calcium fluoride. (thick ppt layer) (reservoir for F release)

chocking off effect

Fluoride released from CaF is then react with hydroxyapatite crystals to form fluoridated hydroxyapatite.

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Advantages of neutral NaF.

Storage stable.

Acceptable taste.

Non-irritant to the gingiva.

No discoloration.

Series f treatments repeated only at the general ages 3, 7, 11 and 13 years old rather than annual or semiannual intervals.

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Disadvantages.

Major disadvantage is the 4 visit technique54

Stannous fluoride 8% , 10% SnF2

Technique of application "Mller's technique"Pumice prophylaxis cleaning for 5: 10 sec.Unwaxed dental floss is passed between the interproximal.Teeth are isolated and air dried.SnF2 is applied using the paint on technique and is kept for 4 mins.Application is repeated semiannual.

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Mechanism of actionStannous fluoride

in low conc. Gives tin hydroxyphosphate metallic taste.

In high conc. Gives calcium tri-fluorostannate + tin tri fluorophosphate. (stable and strong tooth surface)

Calcium fluoride also is the end product of reaction (low and high conc.)56

Advantages of SnF2

Using annual or semiannual usual patient recall system.

Single visit application.

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Disadvantages of SnF2

Not stable in aqueous solution

Unpleasant taste.

Reversible tissue irritation.

Tooth pigmentation of "hypo-calcified regions and margins of restorations".

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Acidulated phosphate fluoride APF 1.23%

Introduced by Brudevold at 1960

Dissolving 20 g of NaF in 1L of 0.1M phosphoric acid with 50% hydrofluoric acid to adjust pH at 3.0 and F concentration at 1.23% "Brudevold's solution".

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Technique of application.

For aqueous preparations of APF the paint on technique is performed.

For gel preparations the tray technique is selected.

Recommended application is repeated annual or semiannual.60

Mechanism of actionAPF

Dehydration and shrinkage of the hydroxyapatite crystals hydrolysis DCPD highly reactive with F

Fluoride penetrates into the crystals more deeply. 61

Advantages of APFSemiannual application per year is compatible with the regular patient recall system.

Gel preparations can be self applied.

Deposits F more deeply and more concentrated.

Stable and don't need fresh preparation.

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Disadvantages of APF

Practical difficulties due to repeated application for every 30 sec. to keep the teeth wet for 4 min.

Acidic, sour and bitter tastes.

Repeated or prolonged exposure of porcelain or composite resin restorations to APF may cause loss of materials, surface roughness and possible cosmetic changes.

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Delivery methods1-self administratedFluoride dentifrices

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Dentifrices "1942"

NaF>>> 0.188: 0.254% with F conc. Of 650ppm.

SnF2 "1950, by Crest">>> not used today.

Monofluorophosphate>>> the most widely used today. Half the fluoride content to produce acute toxicity compared with NaF.Doesn't stain the teeth.Mechanism of action is not absolutely established.0.564: 0.88% with F conc. 800ppm.

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4-Amine fluoride >>>"GABA 1963"

Insoluble metaphosphate.

Less foam than monofluorophosphate.

Superior properties (low rate enamel dissolution, increased F uptake and more anti-glycolytic activity in plaque) compared with NaF and monofluorophosphate.

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Adverse effects

When eaten by children, may experience the phenomenon of PICA and acute F toxicity.

Detergents and flavoring oils may irritate the stomach if ingested in large amounts.

The largest container of toothpaste "270 gm" (family size) contain 270mg of F that still below the Certainly Lethal Dose (CLD)"320 mg", but exceeds the Safely Tolerated Dose (STD) "80 mg F"

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Fluoride mouth rinses

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Fluoride mouth rinses>>>"1946"

Become one of the most widely used caries preventive public health methods.

NaF 0.2% with 900ppm/ week.

NaF 0.05% with 225ppm/day.

Swishing 10 ml for 60 sec.

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Recommendations for fluoride moth rinses.

Rinse and expectorate technique can be used in patients in optimally fluoridated commuinties.

Teaspoonful of NaF 0.05% will deliver 1 mg of F if swallowed.

Swish and swallow technique should be recommended if Fluoride concentration is 0.3 ppm or less.

With special benefits for patient with increased high caries risk "orthodontic patients and patients under radiotherapy".

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Fluoride gel74

Fluoride foam

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Fluoride dental floss

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Fluoride containing chewing gum

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Video club

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Fluoride toxicity(Double edged sword).

Acute toxicity: - Single ingestion of large amount of fluoride.

Nausea >> F combine with H+ in the gastric juice to form HF acid "highly irritant to stomach"

Abdominal cramps.

Vomiting.

Increased salivation.

Dehydration and thirst.

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Fluoride causes death by blocking normal cell metabolism.

Death usually happened in the first 2:3 hrs. due to either cardiac failure or respiratory paralysis.

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Chronic toxicity: - long term ingestion of small amounts of fluoride.

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Dental ->> "Enamel fluorosis"

Excessive intake of fluoride during tooth development.

Fluorosis occurs symmetrically (premolars, 2nd molars, maxillary incisors, canines, 1st molars and mandibular incisors).

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Skeletal ->>

Sever pain in backbones, joints and hips.

Stiffness in joints and spine.

Knock-knee syndrome.

Pregnant and lactating mothers are the most effected groups.

CaF2 is more toxic to fetus than NaF.

May lead to blocking and calcification of blood vessels causing cardiac problems.

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Crippling fluorosis.

Neurological manifestations are seen in very advanced cases. Consumption of 20: 80 mg of fluoride/ day for a period of 10: 20 years.

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94Thank you