TOPICAL FLUORIDES IN

DENTISTRY

TOPICAL FLUORIDES IN DENTISTRY

INTRODUCTION Fluorine is a member of the halogen family

and is the most electronegative and reactive of all the elements.

The word fluorine is derived from the latin term ‘Fluore’ meaning to flow.

Its selective action on the hard tissues of the body attributes significantly to prevention and control of dental caries.

FLUORIDE DELIVERY METHODSFluoride can be delivered as…(A)Topical Fluorides(B)Systemic Fluorides

TOPICAL FLUORIDES SYSTEMIC FLUORIDES

These are placed directly on the teeth

Some preparations

provide high or low concentrations of fluoride over a short period of time

These circulate through the blood stream and are incorporated into developing teeth

They provide a low concentration of fluoride over a long period of time

INDICATIONS Caries active individuals Children shortly after period of tooth eruption Those who take medication that decrease

salivary flow or have received radiation to head and neck

After periodontal surgery when roots of teeth have been exposed

Patients with fixed or removable prosthesis and after placement or replacement of restorations

Patients with an eating disorder or who are undergoing a change in lifestyle which may affect eating or oral hygiene habits conductive to good oral health

Mentally and physically challenged individuals

TOPICAL FLUORIDE PRODUCTS ARE DIVIDED INTO 2 CATEGORIES

(A) Professionally applied Introduced by Bibby in 1942 Dispensed by dental professionals in the dental

office and usually involve the use of high fluoride concentration products ranging from 5000-19000 ppm which is equivalent to 5-9 mg F/ml

(B) Self applied Include fluoride dentifrices, mouth rinses & gels Are low fluoride concentration products ranging from

200-1000ppm or 0.2-1 mgF/ml.

RATIONALE FOR USING TOPICAL FLUORIDE AGENTS To speed up the rate and increase the

concentration of fluoride acquisition above the level which occurs naturally

The initial caries lesion characterized by a white spot is porous and accumulates fluoride at a much higher concentration than adjacent sound enamel

PROFESSIONALLY APPLIED FLUORIDESFLUORIDE VEHICLES AQUEOUS SOLUTIONS AND GELS Gel adheres to the tooth surface for a considerable

amount of time and eliminates the continuous wetting of enamel surfaces when solutions are used

2 or 4 quadrants can be treated simultaneously when trays are used for gel application which results in substantial saving of time

Thyxotrophic solutions are not gels but have high viscosity under storage conditions and become fluid under high stress

Thyxotrophic solutions are more stable at lower ph and don not run off the tray as readily as conventional gels

GELS

FLUORIDATED PROPHYLACTIC PASTES

If prophylaxis pastes containing fluoride are used, the lost fluoride is replenished & there is a significant gain in the concentration of fluoride.

FOAM Developed to minimize the risk of fluoride over

dosage as well as to maintain the efficacy of topical fluoride treatment.

ADVANTAGES: Its lighter than a conventional gel & therefore

only a small amount of agent is needed for topical application

The surfactant has cleansing action by lowering surface tension, this facilitates the penetration of material into interproximal surfaces.

It doesn’t require suctioning so it offers advantages for home use

FOAM

FLUORIDE VARNISH It was first developed by Schimdt in Europe in

1964 Increasing the time of contact between enamel

surface & topical fluoride agents favors the deposition of fluorapatite & fluorhydroxyapatite.

Technique: After prophylaxis teeth are dried but not isolated

with cotton rolls since varnish sticks to cotton Total of 0.3-0.5 ml of varnish is required to cover

full dentition Application is done first done on lower arch then

upper, using single tufted small brush, starting with proximal surfaces

Patient is asked to sit with mouth open for 4 min to let Duraphat set on teeth

FLUORIDE VARNISH

Patient is asked to not rinse or drink anything for one hour and advised liquid diet till next morning

DURAPHAT: It s a viscous yellow material, containing 22,600

ppm fluoride as sodium fluoride in a neutral colophonium base.

FLUORPROTECTOR: Its a clear polyurethane based product containing

7000 ppm fluoride from difluorosilane. It is dispensed in 1ml ampules each ampule

containing 6.21mg of fluoride.

CAREX: It has low fluoride concentration than duraphat &

has equal efficacy to that of duraphat as caries preventive agent

TOPICAL FLUORIDES USED IN PREVENTIVE DENTISTRY:

1.SODIUM FLUORIDE: 2.STANNOUS FLUORIDE 3.ACIDULATED PHOSPHATE FLUORIDE 4.AMINE FLUORIDE

1) NEUTRAL SODIUM FLUORIDE Fluoride concentration - 9200ppm A minimum of four applications with a 2% NaF

solution gives a caries reduction of about 30%

METHOD OF PREPARATION It is prepared by dissolving 20 gms of NaF

powder in 1L of distilled water in a plastic bottle

TECHNIQUE - KNUTSON’S TECHNIQUE

At the initial appointment teeth are cleaned with pumice slurry & then isolated with cotton rolls & dried with compressed air.

Using cotton-tipped applicator sticks ,the 2% NaF is painted on air dried teeth so that all tooth surfaces are visibly wet. The solution is allowed to dry for 3-4 min.

This procedure is repeated for each of the isolated segments until all the teeth are treated.

A 2nd, 3rd and 4th fluoride application, each not preceded by a prophylaxis, is scheduled at intervals of approximately one week;

The four-visit procedure is recommended for ages 3, 7, 11 and 13 years, coinciding with the eruption of different groups of primary and permanent teeth.

MECHANISM OF ACTION :

When NaF is applied on tooth surface it reacts with hydroxyapatite crystals in enamel to form CaF2 which is the dominant product of the reaction

As thick layer of Caf2 forms, it interferes with further diffusion of fluoride from the topical fluoride solution to react with hydroxyapatite and blocks further entry of fluoride ions. This sudden stop of the entry of fluoride is termed as ‘chocking off effect’

CaF2 acts as a reservoir and fluoride slowly leeches out of it

The CaF2 formed reacts with hydroxyapatite fluoridated hydroxyapatite increases the concentration of fluoride on enamel surface prevents caries

ADVANTAGES :

It is relatively stable when kept in a plastic container; The taste is well accepted by patients; The solution is non-irritating to the gingiva; It does not cause discoloration of tooth structure; The series of treatments must be repeated only 4

times in the general age range of 3 to 13, rather than at annual or semiannual intervals.

DISADVANTAGES:

The major disadvantage of the use of sodium fluoride is that the patient must make 4 visits to the dentist within a relatively short period of time.

2) STANNOUS FLUORIDE (SnF2) Fluoride concentration-19500ppm Stannous fluoride has been used at 8% and 10%

concentrations

METHOD OF PREPARATION: Solutions of stannous fluoride are not stable. Soon after

mixing they become cloudy due to the formation of tin hydroxide.

A fresh solution of stannous fluoride be prepared for each patient.

To prepare 8% stannous fluoride solution, the content of one capsule which is 0.8 grams (‘0’ No. of gelation capsule) is dissolved in 10 ml of distilled water in a plastic container.

TECHNIQUE - MUHLER’S TECHNIQUE

Each tooth surface is cleaned with pumice or other dental cleaning agent for 5 to 10 seconds;

Unwaxed dental floss is passed between the interproximal areas;

Teeth are isolated and dried with air; Stannous fluoride is applied using the paint-on

technique and the solution is kept for 4 minutes. Repeat applications are made every 6 months or more frequently if the patient is susceptible to caries.

MECHANISM OF ACTION:

When SnF2 is applied in low concentration tinhydroxyapatite, which gets dissolved in oral tissues

At very high concentration Ca trifluorostannate forms along with tin tri-fluorophosphate

Tin trifluorophosphate is responsible for making the tooth structure more stable and less susceptible to decay

CaF2 is the end product both at low and high concentration which reacts with hydroxyapatite and a small fraction of fluorhydroxyapatite also gets formed

ADVANTAGES :

Using an 8% stannous fluoride solution at 6 to 12 months intervals conforms to the practicing dentist’s usual patient – recall system;

Administrative difficulties are avoided.

DISADVANTAGES :

In aqueous solution the material is not stable; 8% solution is quite astringent and disagreeable in

taste, its application is unpleasant; The solution occasionally causes a reversible tissue

irritation manifested by gingival blanching; Causes pigmentation of teeth which has a

characteristic light brown colour

3) ACIDULATED PHOSPHATE FLUORIDE (APF)

Fluoride concentration-12300 ppm

METHOD OF PREPARATION

An aqueous solution is acidulated phosphate fluoride is prepared by dissolving 20 grams of sodium fluoride in 1 liter of 0.1 M phosphoric acid and to this is added 50% hydrofluoric acid to adjust the pH at 3.0 and fluoride ion concentration at 1.23%. It is also called as Brudevold’s solution

For the preparation of acidulated phosphate fluoride gel, a gelling agent methylcellulose or hydroxyethyl cellulose is added to the solution.

TECHNIQUE

APF is recommended for application at 6 or 12 months interval

Oral prophylaxis is done Teeth to be treated are completely isolated and

thoroughly dried with air Application of gel is done using trays;

disposable foam lined trays are preferred It is reapplied every 15-30sec so as to keep the

teeth moist with the fluoride solution throughout the four min period

The patient is instructed to eat, drink or rinse his mouth for atleast 30 min

FLUORIDE TRAYS

MECHANISM OF ACTION

When APF is applied to teeth it initially leads to dehydration and shrinkage in the vol of hydroxyapatite crystals which on hydrolysis forms an intermediate product called Dicalcium phosphate dihydrate(DCPD)

DCPD is highly reactive and starts forming immediately after APF is applied

Fluoride penetrates into the crystals more deeply through the openings produced by shrinkage and forms fluorapatite

For the conversion of whole DCPD formed into fluorapatite, a deeper penetration and continuous supply of fluoride is required. Because of this reason APF is applied every 30 sec and the teeth have to be kept wet for 4 min

ADVANTAGES

Requires only 2 application in a year; The gel preparation can be self applied and

thus the cost of application also gets reduced; It has the ability to deposit fluoride in enamel to

a deeper depth;

DISADVANTAGES :

Practical difficulties like the teeth should be kept wet for for 4 minutes;

It is acidic, sour and bitter in taste; It cannot be stored in glass containers.

4) AMINE FLUORIDE

They are cariostatic agents Some of them are surface active agents i.e. they

have an affinity for enamel and thus will hold the fluoride for a longer time against the tooth

They also have anti bacterial properties. Reduced plaque formation and anti glycolytic activity is also reported with these compounds

Amine fluorides have been tested in dentifrices, mouthrinses and topical gels where they are either brushed on teeth or applied with a tray but it is not known if they are superior to the other currently available fluoride agents

Characteristics

Sodium fluoride

Stannous fluoride

Apf

Percentage 2% 8% 1.23%

Fluoride concentration (ppm)

9200 19500 12300

ph neutral 2.4-2.8 3.0

Frequency of application

4 at weekly intervals 3,7,11 & 13 yrs

biannually biannually

Adverse effects

no Tooth pigmentationGingival irritation

no

Caries reduction

30% 32% 28%

RECOMMENDATIONS FOR TOPICAL APPLICATION No more than 2 g of gel per tray or

approximately capacity

SELF APPLIED TOPICAL FLUORIDES Dentifrices Mouth rinses Gels

DENTIFRICES The first clinical trial of fluoride dentifrice was

initiated by Bibby in1942 The various compounds used in dentifrice are

sodium fluoride, stannous fluoride, monofluorophosphate and amine fluoride

A 200g tube of Colgate contains 1000ppm of fluoride with the fluoride compound as Monofluorophosphate

A single brushing with a full ribbon of paste on a brush head provides about one gram of toothpaste and will expose the individual to approximately 1mgF

For young children non fluoridated and non abrasive toothpaste is recommended till the child is 4 years of age

After 6 years of age fluoridated toothpaste should be used

The amount should be pea sized and the paste should be pressed into the bristles and not on top of the brush

MOUTHRINSES

Fluoride mouthrinsing is one of the most widely used caries preventive public health methods

Caries preventive agents used are Neutral sodium fluoride, Acidulated phosphate fluoride and Stannous fluoride

Sodium fluoride mouthrinses

Formulated at concentrations of 0.2%(900 ppm F) for weekly use0.05%(225 ppm F) for daily use These are used by forcefully swishing 10ml of the liquid

around the mouth for 60 sec before expectorating it

Recommendations for fluoride mouthrinses

Rinse and expectorate technique used for patients in fluoride deficient communities

In patients with increased caries risk e.g. those undergoing orthodontic treatment or radiotherapy

FLUORIDE GELS

Fluoride gel products include neutral sodium fluoride and acidulated phosphate fluoride with a fluoride concentration of 5000 ppm and stannous fluoride with a concentration of 1000 ppm

The gels are either applied in trays or brushed on teeth

Professionally applied – given twice a year

Self applied – once a day or more Home fluoride gels are not

recommended for children below 6 yrs and younger

Limitations of fluoride gels

They violate the principle of delivering low concentration of fluoride at regular intervals

Toxicity hazard Tedious to use on daily basis

TABLETS AND LOZENGES These are prescribed by the dentist or

pediatrician and are not available over the counter

These provide a topical as well as systemic benefit for both primary and permanent teeth

The amount of fluoride is 0.25mg, 0.5mg or 1mg. These are chewed, swished and swallowed

Correct dosage is based on the conc of fluoride in drinking water, age and weight of the child.

Not more than 1 milligram of fluoride should be ingested from all available systemic sources

Use of these supplements from birth to age 13 or 16 yrs provides caries reduction from 60% to 65%

Conclusion Fluoridation is universally accepted by the

dentists and other medical professionals as being useful in preventing tooth decay

They can be used in areas where there are no central water supplies, where the fluoride conc of well water is low(tablets and lozenges)

REFERENCESEssentials of public health dentistry-

Soben PeterTopical fluorides – Amrit TiwariDental care for children – Anil Kohli

Thank you