Fluoride Guide - IneedCE.com

acid attacks occur, the globules start to break down and release calcium, phosphate
and fluoride, resulting in a higher concentration of these ions at the tooth surface than
internally. These then migrate to demineralized sites and remineralize these defects,
also forming fluoridated hydroxyapatite. (Figure 4)
At lower concentrations of topical fluoride (as used in dentifrices and rinses), fluoride
is retained in solution in saliva as well as being retained as alkali-soluble calcium
fluoride. Thus, topical fluorides result in the retention of fluoride on the tooth surface; in
saliva and dental plaque; and on intra-oral soft tissues, especially the tongue and lower
posterior vestibule of the mouth. 18,19,21
Figure 4. Fluoride adsorption and caries control
Ca ++
F-
Acid Attack
F-
F-
F-
Ca ++ PO 4
PO 4
F-
Acid Attack
F-
F-
High concentrations of topical fluorides result in the formation of calcium fluoride-like globules. These are
stable until exposed to acid, when they release calcium, phosphate and fluoride. Low concentrations
of topical fluorides also result in the presence of bioavailable fluoride in plaque, saliva and oral mucosa.
Together, these mechanisms provide for reservoirs of fluoride available during acid attacks.
Topical fluoride is also believed to inhibit caries activity through bacterial inhibition. 16 (Figure 5)
Figure 5. Bacterial inhibition
Fluoride-induced
inhibition
of enzymes
responsible for
carbohydrate
metabolism
Hydrogen fluoride
molecules enter
the bacterial cell
Fluoride and hydrogen
dissociate, enabling fluoride
activity inside the cell
Fluoride combines with hydrogen and then enters the bacterial cell. Following entry into the cell, the fluoride and
hydrogen dissociate and the fluoride inhibits enyzmes involved in bacterial metabolic processes; this includes inhibition of
enolase that metabolizes fermentable carbohydrates, thereby reducing the production of acid involved in the caries process.
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