Topical Fluoride Therapy
It is a system where by a relatively periodic high concentration of fluoride in dental clinic every 3 or 6 or 12 months, the conc. range from (5000-19000 ppm) and reach to 26000 ppm applied topically to erupted tooth surfaces to prevent or arrest dental caries.
The use of topical fluoride was old since 1945. It can be applied at any time of life that is from tooth eruption and continue the whole life. However the best time of application is in the post eruptive maturation period that is the two years after eruption. The tooth is not fully maturated; ionic exchange will take place between outer enamel surfaces and oral environment. Elements like fluoride, Zn, tin, .. etc continue to incorporate the enamel surfaces.
The main type of reaction is formation of calcium fluoride that is dissolve rapidly there fore to increase F fixation it needs to be applied frequently and continually.
We can increase fixation of F ion on tooth surface by:
1.use of high conc. of F agent in form of complex agent.
2.increase the acidity (break down of enamel surface).
3.increase frequency of application and time of exposure.
Indications (at any age) for
1. prevent or arrest dental caries.
2. sensitive teeth and root caries (periodontal diseases).
3. rampant caries
4. cervical area caries.
5. xerostomia.
6. malnutrient child.
It can be applied inform of solutions, gels, varnishes and prophylactic pastes. Different types of products can be used as sodium fluoride, stannous fluoride, acidulated phosphate fluoride, amine fluoride and others.
Medicaments typically dispensed by dental professional in the dental office setting involve the use of high fluoride concentration products (5 - 19 rag F/ml or even more.
It was introduced by Bibby in 1942 who showed that repeated application of NaF to teeth of children can significantly reduce dental caries.
Types:
It can be used in form of solutions, gel, foam, varnishes or pumices. Different agents can be used as sodium fluoride, stannous fluoride, potassium fluoride. zirconium fluoride, titanium fluoride and others.
Method of applications
1- Tray technique: (foam lined tray or paper lined, or custom vinyl tray).
2. Paint on technique
For both techniques:
- Teeth need to be cleaned (scaling and polishing) for removal of plaque and debris that may interfere with the uptake of fluoride ions and reduce the effectiveness.
- Isolations and dryness using cotton roll and saliva ejector. The head of the patient should be tilted forward to avoid accidental swallowing of the material.
- Application of the material for 1- 4 minutes.
- Use un waxed dental floss to push the material in between the teeth.
- Expectoration several times.
- Avoid eating or drinking for at least 30 minutes.
Sodium Fluoridated agents (NaF):
It was used for the first time by Bibby in 1947.
It is now used in concentration of 2 %. (over 9000 ppm).
Advantage:
1- Chemically stable when stored in plastic or polythene containers.
2- Not irritant to gingival tissues.
3- Does not cause discoloration to teeth.
4- Dental caries reduction about 30%.
It can be used in form of solutions or gels, flavoring and coloring agent can be added.
Indications of use:
-Primary preventive programs for children and adults. It can be applied every 6 months or once a year.
Stannous Fluoride (SnF2):
It was used for the first time in the early 50s by Muhler and co workers. Stannous fluoride contains cation (stannous) and anion (fluoride), both react with enamel surfaces forming calcium fluoride, stannous fluorophosphates and hydrated tin oxide. These complex agents may increase the resistant of surfaces to acid dissolutions, These reactions products depend on concentrations of fluoride ions, acidity (pH) and reaction times.
Ca10(po4)6(OH)2+19SnF2 ? 10caF2+6Sn3F3po4+Sno.H2o
Stannous fluoride used inform of solutions. it is available in powder that is need to be prepared by dissolving appropriate weight in distilled water.
For children the recommended concentration is 8 % (dissolving 0.8 mg. in 10 ml distilled water).
For adolescents and adults the recommended concentration is 10 %( dissolving 1 mg of powder in 10 ml distilled water). The pH is about 2.4- 2.8.
Another concentration are used in form of gel in a concentration of 30 %.
Advantages:
1- Effective in preventing dental caries by increasing resistance of outer enamel surfaces.
2- Re mineralization of initial dental caries.
3- De sensitizations of teeth.
4- Anti plaque specific antibacterial effect against cariogenic bacteria and non specific effect against other types of bacteria .
5- Additive effect by tin ions in addition to fluoride ions.
Disadvantages:
1- Not stable in aqueous solution, it under goes rapid hydrolysis and oxidation to form stannous hydroxide and stannic ions, these may reduce the effectiveness of fluoride. Therefore stannous fluoride solutions need to be freshly prepared.
2- Unpleasant taste, it has metallic and astringent taste. In past flavoring agents were not added as causes reduction in the effectiveness of fluoride. But now a day they add a flavored solution with glycerin and sorbitol to retard hydrolysis of stannous fluoride.
3- Reversible irritation to gingiva, gingival bleaching may occur especially in patient with poor oral hygiene. There for stannous fluoride is not preferable to be used in presence of sever gingival inflammation.
4- Pigmentation and staining of teeth especially in area with carious lesion, hypo calcification, and around margins of restorations.
indications of use:
It can be applied for children as well as adults
1- Primary preventive programs (once a year).
2- High risk groups and rampant caries (every 3 or 6 months).
3- Initial caries (3 or 6 months).
4- De sensitizing agents (Applied once a week, then every 3 months or 6 months).
5- . Patients with Xerostomia (every 3 months).
6- Hypoplasia and hypo calcifications (as cases of amelogensis and dentinogensis imperfecta).
7- Root caries (grade one and two).
Acidulated Phosphate Fluoride (APF):
It was introduced by Brudevld et al (1963). It is sodium fluoride at which acid is added.
The success of any topical fluoridated agents depends on its capability of depositing fluoride ions in the enamel as fluoroapatite and not only as calcium fluoride. Fluoroapatite crystals are stable and not like calcium fluoride that can be easily dissociated to calcium and fluoride ions.
Ca10 (P04)6(OH)2 + 2F?Ca10 (PO4)6 F2 + OH-
There are two ways of speeding up the reactions that lead to formation of fluoroapatite:
1- Increase concentration of fluoride ions in the agent.
2- Lowering the pH, that is making the solution more acidic.
Increase the concentration of fluoride ions however lead to formation of calcium fluoride and phosphate.
The presence of acid leads to the breakdown of the outer enamel surfaces (hydrolysis of hydroxy apatite crystals and release of calcium and phosphate).
In both reactions phosphate formed. The increase in the concentration of phosphate will cause the shift in the equilibrium of the reaction to the right side that is in the direction of formation of hvdroxvanatite and fluoroapatite crystals. In another word the increase in the concentrations of F ions and lowering the pH in presence of phosphate lead to increase deposition of fluoride ions in form of fluoroapatite crystals that is enhancing the fixation of fluoride in the enamel surfaces.
Acidulated phosphate fluoride (APF) is composed of NaF; the concentration of F is 1.23% in addition to acid in form of orthophosphoric acid. The pH is 3.2. It comes in form of (solutions, gel, and foam) to which coloring and flavoring agents can be added.
Advantages:
1- Chemically stable when stored in plastic or polythene containers.
2- Tolerable taste as flavoring agents can be added.
3- Does not cause staining of teeth.
The gel is more preferable than the solution as it increase the time of retention or the materials on the tooth surfaces. The gelling material added is in form of carboxy methyl cellulose. Another type of gelling material can be added known as Thixotrooic gel: this material is highly viscose at low shear rates and low viscose at high shear rate. When used by tray, under pressure the Thixotropic material will flow between teeth and remain in situ and remain stationary. There for it will not flow behind the tray to enter the patient s throat. Both the conventional and Thixotropic A.PF contain the same concentration of fluoride 1.23% the difference between the two is only in the gelling materials.
Indication:
- Primary preventive programs for children and adults.
Amine Fluoride
This an organic fluoride introduced by Muhleman et al 1957. The fluoride ions increase resistance of enamel surfaces to acid dissolution. It has an antibacterial effect by both fluoride ions and organic materials. Thus affect both tooth surfaces and dental plaque.
Fluoridated Varnishes:
It was used for the first time in Germany 1972. The agent used is Duraphat. It is Sodium fluoride in concentration of 2.26% (22600 ppm). It is a viscose yellow material of NaF in an alcoholic solution of natural varnish. It is water tolerant thus can be used even for moist teeth. Varnishes are added to increase time of retention of fluoride to tooth surfaces.
Advantages:
- Increase retention time of agents on tooth surfaces.
- It can be added to certain surfaces and not all teeth.
- It can be applied even in presence of moist teeth.
Indication:
- High risk groups.
- Initial carious lesion even for children under 6 years (can be applied on affected tooth surfaces only).
- Sensitive teeth.
- Root caries (grade one and two).
Fluoride containing prophylactic Paste:
Before applications of fluoridate agents it is recommended to clean the teeth by polishing with a rubber cup using fluoridate pumice. The F paste was first introduced by Bibby and co workers in 1946, using 1 % NaF paste.
Now a day different types are used as:
- Zirconium silicate contains stannous fluoride.
- Silicon dioxide contains acidulated phosphate fluoride.
This paste is not a substitute for the topical agents they are used in order to increase the accessibility of F ions by tooth surfaces. Thorough prophylaxis will remove a thin layer of enamel of 1-4 µm, thus it is always recommended to use F pumice.