Fluoride therapy is widely used to prevent dental caries. Evidence have shown that a constantly maintained low level of fluoride in oral environment is most effective in caries prevention against the earlier popular belief of being it most beneficial against caries during pre-eruptive forming enamel.
Dietary Fluoride supplementation Schedule
American academy of Paediatric Dentistry & American Dental Associations Council on Dental Therapeutics recommend the following regimen for fluoride supplement for an individual having insufficient daily fluoride intake:
|Less than 0.3 ppm F||0.3-0.6 ppm F||More than 0.6 ppm F|
Birth- 6 mos
6 months-3 yrs.
3 yrs.-6 yrs.
|6 yrs. to at least 16 yrs.||1.0 mg||0.5 mg||
Evaluate fluoride exposer before prescribing fluoride therapy. Document the patient’s fluoride exposer in the record and review at periodic visits. Have a water analysis done prior to issuing supplemental fluoride.
Point of use, water conditioning (filtration system significantly reduce fluoride content. Activated carbon filters reduce fluoride concentration by 81%. Bottled water can have variable fluoride concentrations.
Preschool children require supervision during tooth brushing. No more than a pea size amount of tooth paste should be used, avoid swallowing of the pastes & rinse after brushing.
Fluoride mouth rinses containing 0.05% or 0.2% should not be used by children under the age of six years or those who are unable to adequately expectorate.
Supervise professionally applied topical fluoride treatments. Use 5-10 ml of fluoride gel in well fitting brays, ham the patient lean forward in the dental chair, admonish not to swallow, and use a saliva ejector positioned between trays.
Chronic Toxicity (results in fluorosis)
Dean’s Classification 0-4 scale
- 1-very mild
- 59% of population at optimal population level will exhibit no flourosis
- Very mild 7.4 % of population at optimal dose.
- (mild) greater than 25%, less than 50% of surface with opaque defect (greater than 1.2 ppm)
- (Moderate) brown stains present (greater than 2 ppm).
- (Severe) pitting and attrition problems (greater them 2-3 ppm)
Flourosis occurs during maturation process. For incisors, age 2-3 yrs is the critical period.
CLD (certain lethal dose 32-64 mg/kg body wt in one source,71-140 mf/kg in another source. A death has been reported at 17 mg/kg.
PTD (Probable Toxic Dose) 5mg/kg i.e.50 mg for a 10 kg 2 yrs old.
STD (Safely Tolerated Dose) 8-16 mg/kg
Toxicity at low doses is due to gastric irritation.
Hypocalcaemia and hyperkalemia at high doses leads to cardiovascular collapse and death.
Treatment of Overdose
- Less than 5 mg/kg-oral calcium (milk) and observe
- More than 5 mg but less than 15 mg/kg- induce vomiting, oral calcium (milk, calcium gluconate, calcium lactate, admit to hospital
- More than 15 mg/kg- admit to hospital immediately, induce vomiting, monitor cardiac function, 10% calcium gluconate solution IV and monitor electrolytes.
COMMON SIGNS AND SYMPTOMS OF ACUTE FLUORIDE TOXICITY
- Hyper salivation
- Abdominal pain
- Cardiac arrhythemia
- Patients become hypocalcaemic due to Ca binding with fluoride.
Calculating mg Fluoride in Compound
Ist step: Find % F in compound
|Name||Molecular weight ratio|
1/2.2 or 1/2
1/4.1 or 1/4
|MFP-sodium Mono fluoro Phosphate||
1/7.6 or 1/8
Multiply % compound by molecular weight ratio= % F
2nd Step: Express % Fluoride in compound in mg F/ml
By definition % solution is gram/100 ml.
Gram/100 ml=1000mg/100 ml=10 mg/ml
Multiply step 1 by 10 = mgF/ml
3rd Step: Multiply step 2 by ml ingested to get mg F ingested
- 23% APF x 1 = 1.23% F x 10 = 12.3 mg F / ml
- 2% NaF x 1/2 = 0.1 x10 = 1 mg F / ml
- 2% NaF x 1/2 = 1 x 10 =10 mg F / ml
- 4 % SnF2 x ¼ = 0.1 x 10 mg = 1 mg F / ml
- 10% SnF2 x 1/4 = 2.5% x 10 =25 mg F / ml
Compare with CLD and STD for weight of individual
Decrease in caries activity
- Secondary- 50-60%
MECHANISM OF ACTION OF FLUORIDE
- Decreases enamel solubility.
- Improves enamel crystalinity.
- Promotes re mineralisation.
- Decreases free surface energy of bacteria so it cannot stick on tooth.
- Bactericidal or bacteriostatic
- Causes developing crystal to get bigger and less soluble
- Home use in trays, topical
- H2O supply
- Systemic also topical when chewing tablets
- High frequency low dose is effective
- Efficacy due to physical obstruction of pit & fissures.
- May be used over sites with incipient and active caries.
- Effective for primary teeth.
- Fluoride releasing sealants.
- Sealant failures occur during first year, check closely and repair.
- Dentin bonding agent improves sealant bond wet environment.
- Timing: Increase failure (54%) with occlusal gingival tags.
Fluoride mouth rinses
Reduce caries by 20-50 %. Weekly 0.2% NaF and daily 0.05% NaF rinses were considered to be ideal public health measure.
- 0.02% acidulated phosphated fluoride.
- NaF (100 ppm).
- Partly acidulated solution of 0.04% NaF (200 ppm).
Weekly or fortnightly rinses
- 0.2% NaF (1000 ppm).
- Patients who are undergoing orthodontics treatment.
- Post-irradiation xerostomia Sufferers.
- Children unable to perform adequate tooth brushing.
- Non recommended for preschool aged children.
- Reduction in caries rate-30 %
- Hypersensitive areas.
- Newly erupted tooth.
- Arresting early caries.
- is an alcoholic solution of natural varnishes.
- contains 50 mg NaF/ml (2.5%=25000 ppm F)
- A silane fluoride varnish in a poly polyurathane lacquer.
- Contains lower concentration of fluoride 0.8%.
With such highly concentrated fluoride products, great care must be taken to avoid overuse & ingestion. They should not be used before the eruption of permanent incisors.
- before fluoride application is not usually needed.
- may acts as reservoir of fluoride.
Concentrated fluoride gels and solutions:
APF (Acidulated Phosphate Fluorides – 1.23 % F ie 12,300 ppm F
- AFP gels are mainly used for the prevention of caries development.
- Used for professional application.
- Has a mixture of NaF, HF and orthophosphate acid.
- Should be limited for professional use.
- Should not be dispensed for home use.
- Incorporation of a water soluble polymer i.e. Sodium carboxymethyl cellulose into APF produces a viscous solution that improves the ease of application using custom made trays.
- Thixotropic gels in tray flow under pressure, so facilitating the penetration of the gel between teeth.
Neutral NaF 2.2%
- Preferred in cases of erosion, exposed dentin ‘Calais dentin Or where very porous enamel exist.
- Chemically very Stable, has an acceptable taste, nonirritating to the gingival docs not discolors teeth, composite or porcelain restorations as APF or stannous fluoride may.
Stannous fluoride Sn F2
- 10%.Sn F2 is used to target local at risk surfaces of teeth such as deep fissures & pits.
- Rapid penetration of tin and fluoride into enamel and the formation of a highly insoluble tin-fluorophosphates complex coating on the enamel are the main mechanisms of its action.
- Often produces discoloration of teeth and staining on margins of restorations-particularly in hypocalcified areas.
- 0.4% SF2 get in a methylcellulose and glycerin base has proved effective in arresting root caries. It has been incorporated into a synthetic Saliva solution to reduce caries in post-irradiation cancer patient.
- Fluoride supplement (tablets & drops have limited application as a public health measure but may be of benefit to individuals with a high caries brisk.
- Beneficial in non-fluoridated communities. Benefit is small.
- Overzealous use –Fluorosis.
- Fluoride tablets should be chewed rather than swallowed-both topical & systemic benefit.
- In the Period between 2-3 years maxillary incisor teeth are most susceptible to fluorosis.
Daily F supplement doses schedule for persons concerned at particularly high caries risk
F level in water <0.3 mg/L
|F level in water 0.3-0.5 mg/L|
6 monthts-4 yrs.
> 8 yrs.
*All supplement should be formulated as lozenges,
*A person whose daily dose is 0.5 mg should consume 0.25 mg tablet two times daily.
Take the Mock Test 15: Fluoride Therapy by clicking HERE.