Fluorides Delivery Methods

Chetan Basnet

BDS IV Batch

III Year

Fluorides Delivery Methods

Fluorides can be delivered as :-Topical Fluorides

Systemic Fluorides

Topical Fluorides

Topical Fluorides:-Topical fluorides are applied directly on the teeth. “Topically Applied

Fluoride” is used to describe those delivery systems which provide fluoride for a local chemical reaction to the exposed surfaces of the erupted dentition. The delivery system includes measures designed for professional application such as fluoride – containing prophylactic pastes, solutions, gels, and varnishes as well as systems deigned for unsupervised home use, such as fluoride dentifrices and rinses.

Indications for topical Fluorides

1. Caries-active individuals i.e. those with past caries experience or those who develop new carious lession on smooth tooth surfaces.

2. Children shortly after periods of tooth eruption, especially those who are not carries free.

3. Medication to reduce salivary flow or had undergone head and neck radiation.

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. 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.

7. Mentally or physically challenged individuals.

Topical Fluorides products can be divided into two broad categories:-

Professionally Applied Fluorides Product

Self Applied Fluorides Products

Professionally Applied Fluorides Products :-These are the medicaments typically dispensed by dental

professionals in the dental office and usually involve the use of high fluorides concentration products, ranging from 5000 and 1900 ppm which is equivalent to 5-19 mgF/ml.

History:Bibby in 1942 was the first to demonstrate that the, repeated

application of sodium or potassium fluorides to teeth of children significantly reduced their carries prevalence. This achievements became the fore runner of many studies to test the effectiveness of various topical fluorides and the effective methods of its application.

Topically fluoride application by a Dentist , Dental Hygienist or any other Dental Auxiliary has become an established Caries-Preventive Procedure in the Dental History. The three agents currently used as professionally applied fluorides are:-

1. Neutral Sodium Fluoride (NaF)2. Acidulated Phosphate Fluoride (APF)3. Stannous Fluoride (SnF2)

The fluoride may be used in an aqueous solution, a viscous gel, a prophylactic paste or as a dental varnish and can be applied using the Paint on Technique or the Tray Technique.

Paint on TechniqueApplication procedure

Although it is not necessary to do a professional Prophylaxis prior to the application of a fluoride varnish, it is recommended that the teeth be cleaned with a toothbrush.

Wiping with a cotton gauze is adequate in cases where there is no heavy plaque or debris.

The teeth should be lightly dried with air or a cotton gauze.

The varnish will adhere even if the teeth are moist.

Isolate the teeth (e.g. with cotton rolls) to prevent recontamination with saliva

A small amount of varnish (e.g. 0.5ml) is dispensed. The entire dentition may be treated with as little as 0.3-0.6 ml.

A small brush or applicator is then used to apply the varnish

The varnish will set on contact with the slightly moist teeth

The patient is instructed to avoid brushing for the rest of the day. Normal oral hygiene procedures can begin again the following day As a result of the time needed for frequent reloading of the brush/applicator, Hodgson (2005) has suggested an alternative technique utilizing a 5 ml plastic syringe. This method

allows a more efficient application of the varnish which can be particularly useful in cases where speed is important, such as with a difficult pediatric patient.

In order to be effective in decay prevention the varnish should be reapplied at least twice yearly.

Tray Technique

How to Use Custom Fluoride Carriers (Trays)

Brush teeth thoroughly with soft toothbrush and regular toothpaste. Floss teeth using unwaxed dental floss . It is very important to remove all food and plaque from between teeth before using

fluoride. Food and plaque can prevent the fluoride from reaching the surface of the tooth.

Place a thin ribbon of the fluoride gel into each upper and lower fluoride tray so that each tooth space has some fluoride. Either 0.4% stannous fluoride or 1.1% sodium fluoride. The fluoride can

be spread into a thin film that coats the inside of the trays, by using a cotton-tipped applicator, finger or toothbrush.

Seat the trays on the upper and lower arches and let them remain in place for 5 minutes. Only a small amount of fluoride should come out of the base of the trays when they are placed,

otherwise, there may be too much fluoride in the trays.

After 5 minutes, remove the trays and thoroughly expectorate (spit out) the residual fluoride. Very Important – do not rinse mouth, drink or eat for at least 30 minutes after fluoride

use.

Care for Fluoride Carriers (Trays)

• Rinse and dry the trays thoroughly after each use. Clean them by brushing them with a toothbrush and toothpaste.

• Occasionally, the trays can be disinfected in a solution of sodium hypochlorite (Clorox) and water. Use one tablespoon of Clorox in about one-half cup of water. Soak them for about 15 minutes.

• If the trays become covered with hard water deposits, soak them in white vinegar overnight and brush them the next morning.

• Do not boil the trays or leave them in a hot car as they may warp or melt.

Neutral Sodium Fluoride (NaF)

Neutral Sodium Fluoride(NaF) was the first fluoride compound to be used for topical fluoride application. A minimum of four applications of with 2% Sodium Fluoride solution gives a caries reduction of about 30%.

Methods of preparation of 2% NaFIt is prepared by dissolving 20gm of Sodium Fluoride powder in

one liter(1000ml) of distilled water in plastic bottle. It is essential to use plastic bottles because if stored in glass bottles it may react with silica and form Silicon Fluoride thus by reducing the availability of free active fluoride of anti-caries action.

Procedure for application of Sodium Fluoride

[ Knutsons Technique ]:

If the Sodium Fluoride reagent is pure and uncontaminated, the solution has pH of 7. The treatment is carried under four series of appointments.

Teeth cleaned with aqueous pumice slurry

dry with compressed air

teeth isolated either by quadrant or by half mouth

2% NaF solution is painted on the air dried teeth so that all surfaces are visibly wet

allowed to dry for 3-4 minutes

repeated for each of the isolated segments until all teeth are treated2nd, 3rd and 4th NaF application, each not preceded by a prophylaxis, is

scheduled at intervals of approximately one week.The fourth visit procedure is recommended for ages 3,7,11 and 13 yrs, coinciding with the eruption of different age groups of primary and permanent teeth. Thus, most of the teeth will be treated soon after their eruption, maximizing the protection afforded by topical application.

Mechanism of Action

NaF Hydroxyapatite crystals Calcium Fluoride reacts forms

“Chocking Off Effect”[as thick layer of formation of Calcium fluoride forms , it interferes diffusion of F from

NaF solution to react with hydroxyapatite and blocks further entry of F ions]And acts as resorvior for F release [it is the reason allowed to dry for 3-4 minutes]

Calcium Fluoride Hydroxyapatite crystals Fluoridated Hydroxyapatite

increase of fluoride content on enamel surface resistance against caries attack

Advantages :• Relatively stable when kept on a plastic bottles • Taste well accepted by patients.• Non- irritant to Gingiva• Doesn't results in discoloration of teeth• Once applied allowed to dry for 3-4 min so can pursue a multiple-chair

procedure in public health programme.• The series of treatment must be repeated only four times in general age range

of 3-13 yrs rather than annual or semiannual intervals, therefore in public health program , other group of children can be treated in intervening yrs.

Disadvantages:• The only disadvantage is that the patient has to make four consecutive visits

within a short period of time.

Stannous Fluoride(SnF2)

Stannous Fluoride has been used at 8% and 10% concentrations in solutions equivalent to 2 and 2.5% fluoride. Although 10% solutions used for adults and 8% for children there is no any clinical difference between the two. However 8% Stannous Fluoride is preferred.

Methods of Preparation of Stannous FluorideSolutions of Stannous Fluoride are not stable so soon after

mixing they become cloudy due to formation of Tin Hydroxide reducing the agents effectiveness. Since, Stannous is believed to contribute to anticarries benefits, aged solutions are considered to be clinically less effective so Muhler et al recommended to use fresh solutions of Stannous Fluoride for each patients.

To prepare 8%Stannous Fluoride solution the content of one capsule which is 0.8 gm(‘0’ no. gelation capsule) is dissolved in 10ml of distilled water in the plastic bottles and shaken briefly.

Procedure for application of Stannous Flouride

[ Muhler’s Technique ]

Teeth cleaned with aqueous pumice slurry

Un-waxed dental floss is passed between the inter-proximal areas. (unwaxed dental floss has been recommended and continues to be used because it is believed that waxed dental floss may coat tooth surface and adversely affect fluoride uptake.)

Teeth are isolated and dried with air.

SnF2 is applied using the paint on technique and the solution is kept for 4 min.

Repeat applications are made every 6 months or more frequently if patients is susceptible to caries.

Mechanism of Action

SnF2 Low concn tin Hydroxyphosphate oral fluids dissolve it forms gets

”metallic taste application”

SnF2 high concentration

Calcium tri-fluoro-stannate Tin tri-fluoro-phosphate

“Tin tri-fluoro-phosphate makes tooth surface more stable & less suspectibility to decay”

Calcium fluoride is also formed both at high and low concn which reacts with hydroxyapatite and results in formation of fluorohydroxyapatite.

Advantages:– Using 8% Stannous Fluoride solution at 6-12 months intervals

conforms to the practicing dentist’s usual patient – recall system.– Administrative difficulties, particularly in public health programs.

Disadvantages:– In aqueous solution the Stannous Fluoride is not stable.– Since 8% solution is quite astringent and disagreeable in taste, its application is

unpleasant– The solution usually causes reversible tissue irritation manifestoed by gingival

blanching usually on individuals with poor oral hygiene.– It usually causes pigmentation on teeth which has characteristic light brown

color. Staining usually appears in association with carious lesions, hypo calcified regions and around margins of restorations.

Acidulated Phosphate Fluoride (APF)

Acidulated Phosphate fluoride was introduced in1960’s by Brudevold and his co-workers at the Forsyth Dental Center, Boston, Massachusetts.

Methods of preparation of Acidulated Phosphate FluorideAn aqueous solution of Acidulated Phosphate Fluoride is prepared by

dissolving 20gms of Sodium Fluoride in 1 l of 0.1 M phosphoric acid and then 50% hydrofluoric acid added 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 and the pH is adjusted between 4-5.

Procedure for application of Acidulated Phosphate Fluoride

The preferred methods of application of using Acidulated Phosphate Fluoride is by paint on technique and for gel preparation the tray technique accepted . It is recommended for application at 6-12 months intervals.

The patient seated upright position in chair & Oral prophylaxis is done& teeth are treated completely.

Clinical application of APF gel by tray technique [disposable foam line tray is preferred]

To reduce ingestion a minimal amount of fluoride gel kept [coverage of tooth surfaces ,<5ml ]

saliva ejector is used to wipe out saliva and excess fluoride

reapplied after every 15-20 seconds so as to keep the teeth moist with fluoride solution through out 4 min

The patient is told not to swallow the gel but to exert slight pressure using the cheeks and the tongue as well as light biting forces in order to cause the gel to flow inter-proximally. The fluoride gel should be in mouth for 4 min

and remaining oral fluids should be expectorated.

The patient is instructed not to eat drink or rinse his mouth for at least 30 min.

Mechanism of Action

APF applied

Initially leads to dehydration & shrinkage of hydroxyapatite crystalshydrolysis

Dicalcium phosphate dihydrate (DCPD)highly reactive with fluoride ion

Fluoride penetrates into crystals deeply through openings produced by shrinkage and leads to formation of Fluoroapatite

The amount of Fluoroapatite deposited dependent on DCPD formation. For conversion of DCPD into fluoroapatite deeper penetration and continuous supply of Fluoride required. Hence APF soln was applied at 30 sec intervals and teeth kept wet for 4 min.High fluoride concn and low pH, favours fluoride deposition, acidification of fluoride soln with phosphoric acid found to suppress dissolution of enamel, as well as formation of calcium fluoride

The intermediate product Dicalcium phosphate & principal reaction product Calcium fluoride

Advantages:• Requires only 2 application in a year and is thus suited for most dental office

routines.• The gel preparation can be self applied and the cost of application also gets

reduced.• It has the ability to deposit fluoride in enamel to a deeper depth than a neutral

Sodium Fluoride or Stannous Fluoride.• Acidulated Phosphate Fluoride is stable and need not be freshly prepared for each

individual.

Disadvantages:• Practical difficulties like the teeth should be kept wet for four minutes so repeated

application necessitates the use of suction thereby minimizing its use in the field. This also increase the chair side time making this methods more expensive.

• It is acidic, sour and bitter in taste.• It cannot be stored in glass container.

ComparisonCharacterstics Sodium Flouride

(NaF)Stannous Fluoride (SnF2)

APF

Percentage 2% 8% 1.23%

Fluoride concn.(ppm) 9,200 19,500 12,300

pH Neutral 2.4 - 2.8 3.0

Frequency of Application 4 at weelky intervals3,7,11,13 yrs

Biannually Biannually

Adverse effect - Tooth pigmentationGingival irritation

-

Caries reduction 30% 32% 28%

Recommendation For Topical Fluoride Application

According to Lecompte (1987), the recommendation for Topical Application of high potency fluorides are:-

1. Not more than 2gm of gel per tray or approximately 40% of tray capacity should be dispended. Even more conservative amount should be considered for small children.

2. To prevent the swallowing of saliva during 4 min topical application , use of Saliva Ejector is recommended.

3. Following the 4 min of application procedure, the patient should be instructed to expectorate thoroughly for from 30 sec-1 min, regardless the use of suction cause the Expectoration is the only single most effective way of reducing orally retained fluoride.

4. When utilising custom individually fitted trays for patients requiring daily or weekly application of a high fluoride concentration product utilise only 5-10 drops of products per tray.

Self Applied Topical Fluorides

Self applied fluorides products are usually bought and dispended by the individual patient but at the recommendation of a dental professional. These fluoride products are of low concentration ranging from 200-1000 ppm or 0.2-1.0 mgF/ml. The self applied fluoride usually are:-

1.Fluoride Dentifrices2.Fluoride gels 3.Fluoride rinse

Fluoride DentifricesFluoride Dentifrices plays a significant role in in caries prevention since it

requires active participation by the patient to have any effect. It has been demonstrated that the subject who brush twice a day or more with 1000 ppm or, 1500 ppm or, 2500 ppm fluoride dentifrices, have significantly reduced caries prevalence.

History• The first clinical trial of a fluoride dentifrices was initiated by Bibby in 1942. The

active agent was Sodium Fluoride which had been added to a conventional dentifrices containing Dicalcium phosphate as the abrasive.

• In 1945 Muhler et al reported a clinical trial that tested stannous fluoride in a paste with a new calcium pyrophosphate abrasive system.

• In 1955, the stannous fluoride dentrifice became the the first dentrifice recognized by FDA [Food and Drug Administration] as an effective tooth decay preventive product which was later accepted by ADA [American Dental Association].

Fluoride Compounds in Dentifrice1. Sodium Fluoride Dentifrice2. Stannous Fluoride Dentifrice3. Monofluorophosphate4. Amine Fluoride Dentifrice

Fluoride Mouth Rinses• The use of fluoride mouth rinses was first described by Bibby et al in 1946.• In1979 the Council of Dental Therapeutics of American Dental Association acepted

Neutral Sodium fluoride and Acidulated Phosphate Fluoride mouth rinses as effective caries preventive agents.

Sodium Fluoride Mouth rinses• They are usually formulated at concentrations of either0.2%(900ppm F)

for weekly use or 0.05%(225 ppm F) for daily use.• These rinses are intended to be used forcefully swishing 10ml of the liquid

around mouth for 60 sec before expectoring it.

Advantages of Daily Rinsing• If the patient misses several sessions it is probably less critical than if he was on a

weekly schedule.• Advantage of 0.05% Sodium Fluoride concentration is that it can be used to

produce topical as well as systemic benefit when indicated for individual patient.

Fluoride GelsFluoride gels products includes neutral sodium fluoride and acidulated phosphate fluoride with a

fluoride concentration of 5000 ppm and stannous fluoride with1000 ppm. The stannous fluorides products usually called gels, but actually are glycerin based solutions.

• The gels are applied either b y brushing or in trays.• Professionally, applied fluoride given twice a year while self applied fluoride can be once a

day or more.• Patients brush their teeth for 1 min with a gell or if trays used several drops are placed in

each tray and applied for 5 min. Patient should be informed to expectorate the gel and not to swallow. And should rinse mouth after the application so as to minimize the risk of swallowing gels by children and usually not recommended for children 6 years or younger.

Limitation of Fluoride Gels They violate the principle of delivering low concentration of

fluoride at regular intervals. High concentrations of fluorides deposit calcium fluoride on teeth rather than forming hydroxyapatite.

They present a toxicity hazard as relatively large amounts of fluorides are given in uncontrolled manner to people of varying intelligence.

They are tedious to use on daily basis over a long period of time. However they may be a value when prescribed professionally for use at home especially for high risk subjects.

Systemic FluoridesThey circulate through the blood stream and are incorporated into the

developing teeth. They provide a low concentration of fluoride over a long period of time. Some fluoride preparations provide both topical and systemic effects i.e. when fluoride oral rinse are used they are swished for topical effects and swallowed for systemic effects.

The different types of Systemic fluorides are:I. Water Fluoridation

i. Community Water Fluoridationii. School Water Fluoridation

II. Salt FluoridationIII. Milk FluoridationIV. Fluoride tablets/ drops/ lozenges

When fluoride appropriately used, is safe and effective agent that can be used to prevent and control dental caries. Fluoride has been contributing to improve the dental health of persons all over the world. Fluoride is needed regularly to prevent and protect the teeth from being decayed.

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