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Mechanisms of Action of Fluoride

a) Fluoride works in three ways to reduce and prevent tooth decay: 1) systemically, by being ingested and incorporated into the enamel structure during tooth development; 2) topically, by promoting remineralization and inhibiting demineralization of tooth surfaces after eruption; 3) topically, by inhibiting glycolysis in microorganisms, thereby hindering the ability of bacteria to metabolize carbohydrates and produce acid. The greatest effect on reducing and preventing decay is topical; however, both systemic and topical mechanisms are important.

b) Systemic fluoride is ingested, or taken into body during consumption of foods or beverages. Today it is accepted that the systemic effect on caries prevention is the lesser effect; however, there is current evidence that systemic exposure to fluoride during tooth formation reduces tooth decay.

c) Topical fluoride concentrates in the plaque and saliva, thereby enabling it to come into frequent contact with the surfaces of the teeth. Its effects are post eruptive and can benefit people of nearly all ages by reducing decay on both the coronal and root surfaces.

d) One reason why water fluoridation is the most effective method of fluoride delivery is that populations consume small quantities of water throughout the day, not just a couple of times when they brush their teeth or eat. Therefore, on a regular basis, water fluoridation replenishes small quantities of fluoride to the plaque and saliva, which contributes to good oral health.

e) Systemic fluorides also provides a topical effect because saliva contains some fluoride from indigestion, is continually available at the tooth surface, and becomes concentrated in dental plaque where it inhibits acid-producing cariogenic bacteria from demineralising tooth enamel. Fluoride concentration in the plaque is 50 to 100 times higher than in the whole saliva.

f) In summary, fluoridation has been found to reduce dental decay through three mechanisms: 1) by systemic indigestion of fluoride, which is incorporated into the developing tooth structure reducing the solubility of tooth enamel in acid and making it more resistant to decay; 2) by topical action of fluoride in the plaque and saliva, which enhances remineralisation of tooth enamel that has been demineralised by acids produced by decay-causing bacteria, 3) by topical interaction with bacteria in the plaque, which reduce the acid production by dental-plaque organisms.

1. Decide if the sentences are True or False.

a) Fluoride works in three ways to increase tooth decay.

b) The greatest effect on reducing and preventing decay is topical.

c) Systemic fluoride is ingested into the body during eating.

d) It is evident that systemic exposure to fluoride during tooth formation extents tooth decay.

e) Topical fluoride concentrates in the plaque and saliva.

f) Its effects are post eruptive and can benefit people of nearly all ages.

g) Systemic fluorides do not provide a topical effect.

2. In which paragraph is said about the following:

1 – fluoride concentration in the plaque is higher than in the whole saliva ___

2 – topical fluorides come into frequent contact with the surfaces of the teeth ___

3 – dental decay may be reduced greatly due to fluoridation ___

4 – the largest effect on reducing and preventing decay is topical ___

5 – on a regular basis water fluoridation contributes to good oral health ___

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