FLUORIDE AND THEIR ROLE IN DENTAL CARIES PREVENTIONFluoride

• Natural mineral nutrient• Derived from fluorine• Found in soils rich in: Fluospar (Calcium

Fluoride), Cryolite (Sodium Aluminum Fluoride)

• Found in in plants, food, and body tissues• In humans , it is found mainly in calcified

structures-- teeth and bones

• Normal bone : 0.01 to 0.3 % fluoride• Dental enamel : 0.01 to 0.02 % fluoride• Carious teeth : 0.0069 % fluoride• Optimum level: 1.0 part per million (ppm)• Total fluoride intake (food and water): 1.2

mg (non-fluoridated) & 3.5-4.5 mg (fluoridated)

• Rich sources: seafoods (salmon, sardines) = around 1.6 ppm; tea (1.5 ppm)

Fluoridation - The process of adding fluoride to the water supply.Effects of Fluoride:

• Helps in the development of healthy teeth and bones

• Absorbed almost entirely through the bloodstream from the GI tract.

• Also absorbed through the lungs - occupational hazards.

Tooth DevelopmentWhen the fluoride reaches the tooth, it replaces part of the tooth structure called hydroxyl ion, which is on the surface of the apatite crystal in the enamel.The new structure that is formed is called fluorapatite crystal.During the pre-eruption stage, fluoride ion replaces the hydroxyl ion when the teeth are calcifying.

Excessive amount of fluoride in this stage may disturb the normal pattern of tooth development, resulting to fluorosis or mottled enamel.During the post-eruption stage, the absorption rate of fluoride is in its highest just after the tooth has erupted, then it tapers off as the enamel matures. Once the teeth have erupted, they receive fluoride through the bloodstream and through exposure in the oral cavity to fluoride --toothpastes, tablets, gels, and rinses.Fluoride ToxicityToxicity of fluorides depends on the duration and dosage of ingestion.Fluoride used in dentistry presents little or no risk for acute toxicity.Dangers Associated with Fluoride Ingestion

1. Acute fluoride poisoning – large amounts of fluoride are ingested, inhaled, or absorbed into the body at one time.

*lethal dose - varies from 2.5 to 10 grams in adults, 0.25 grams in infants

2. Chronic fluoride poisoning - ingestion of high fluoride sources over a period of time.

2 effects of chronic fluoride overdose:1. Crippling fluorosis- skeletal

hypermineralization of ligaments2. Mottled enamel

Appearance of teeth with exposure to fluoride:Between 0.7 to 1.2 ppm (optimum level): Teeth are white, opaque and shiny without blemish.Exposure up to 1.8ppm: The structure of enamel is not affected, but chalky bands or flecks can be seen in the surfaceExposure over 1.8 ppm: Chalky bands or flecks appear on the surface and the enamel structure is affected - Enamel Hypocalcification.

-The chalky bands and flecks discolor with time. With increased exposure to fluoride, the enamel may crack and become pitted.Benefits of FluorideThe benefits are in proportion to the length of time an individual received fluoride and the amount of fluoride given.Primary benefit: reduction of dental caries.

• Less or no premature loss of deciduous teeth

• Less malocclusion• Less permanent tooth loss• Healthier periodontal tissues

Forms of Fluoride used in Dentistry2 forms of fluoride available for dental care:

1. Systemic fluoride2. Topical fluoride

Fluoride compounds used in dentistry:• Sodium fluoride• Stannous fluoride• Acidulated phosphate fluoride

* Sodium Fluoride• Ingested and circulated through the body to

the developing teeth• Sources : fluoridated water, food, tablets

and dropsFood: meat, vegetables, cereals and citrus fruits have small amount of fluorideTea and fish have slightly higher amount of fluoride* Topical Fluoride

• Resists demineralization of tooth• Assists in the remineralization of decalcified

areas• Available for direct application in forms of

gels, rinses, foams, and liquids. • Chewables has dual benefit (topical and

systemic)Advantages and disadvantages of fluoride preparations:Neutral- 2% Sodium Fluoride

• Relatively stable• Agreeable taste• Non-irritating to soft tissues• Do not discolor teeth or restorative

materials• Must be used at one week interval for four

weeks• Applied for 3 mins• Ages 3, 7, 11, 13 for complete therapy

8% Stannous Fluoride• Not stable • Has disagreeable taste• Astringent• Cause gingival blanching• Causes discoloration of teeth due to tin

content1.23 % Acidulated Phosphate fluoride (APF)

• Commonly preferred because of greater uptake of fluoride by the surface of enamel of the tooth.

• Do not irritate soft tissues• Do not discolor teeth• Slightly astringent• Becomes more acidic when stored in glass

container• 4 min application• Six to twelve months interval