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[[File:UNN_Medical_Geology_Fig_7.png|thumb|400px|{{figure number|7}}(A) Rickets (skeletal fluorosis) in a three year old child; (B) Dental fluorosis.<ref name=Setal2010 />]]

[[File:UNN_Medical_Geology_Fig_7.png|thumb|400px|{{figure number|7}}(A) Rickets (skeletal fluorosis) in a three year old child; (B) Dental fluorosis.<ref name=Setal2010 />]]

With an electronegative value of 4.0, fluorine is the most reactive element on earth. It has very low dissociation energy. This means that it has the tendency to accept electrons from other elements, and has the greatest ease to form strong bonds. The fluoride ion has an ionic radius of 1.33 Ȧ and an ionic charge of -1; this is similar to that of the hydroxyl ion which has ionic charge of -1 and ionic radius of 1.32 Ȧ<ref name=Schmschula>Schamschula, R. C. and D. E. Barmes, 1981. Fluoride and health: Dental Caries, Osteoporosis and Cardiovascular Disease. Annual Review of Nutrient, 1, 427–35.</ref>

With an electronegative value of 4.0, fluorine is the most reactive element on earth. It has very low dissociation energy. This means that it has the tendency to accept electrons from other elements, and has the greatest ease to form strong bonds. The fluoride ion has an ionic radius of 1.33 Ȧ and an ionic charge of -1; this is similar to that of the hydroxyl ion which has ionic charge of -1 and ionic radius of 1.32 Ȧ<ref name=Schmschula>Schamschula, R. C. and D. E. Barmes, 1981, Fluoride and health: Dental caries, osteoporosis and cardiovascular disease: Annual Review of Nutrient, v. 1, p. 427–35.</ref>

Fluoride (F-), the ionic form of fluorine, can stimulate bone formation and it also has been demonstrated to reduce dental caries at doses of at least 0.7 mg/l in drinking water.<ref name=Setal2013 /> Concentration in the excess of this figure leads to adverse health effects called fluorosis (Table 4). Dental fluorosis occurs when the fluoride ions continually substitute for hydroxyl ions in the apatite [Ca10 (PO4)6(OH, F, Cl, Br)2] crystals of the enamel. The enamel loses its glittering appearance as chalky white patches develop; this is called mottled enamel.<ref name=Schmschula /> Dental fluorosis proceeds to change the colour of the teeth from chalky white to yellow, brown or black. Finally, the yellow, brown or black patches become dissolved ([[:File:UNN_Medical_Geology_Fig_7.png|Figure 7]]).

Fluoride (F-), the ionic form of fluorine, can stimulate bone formation and it also has been demonstrated to reduce dental caries at doses of at least 0.7 mg/l in drinking water.<ref name=Setal2013 /> Concentration in the excess of this figure leads to adverse health effects called fluorosis (Table 4). Dental fluorosis occurs when the fluoride ions continually substitute for hydroxyl ions in the apatite [Ca10 (PO4)6(OH, F, Cl, Br)2] crystals of the enamel. The enamel loses its glittering appearance as chalky white patches develop; this is called mottled enamel.<ref name=Schmschula /> Dental fluorosis proceeds to change the colour of the teeth from chalky white to yellow, brown or black. Finally, the yellow, brown or black patches become dissolved ([[:File:UNN_Medical_Geology_Fig_7.png|Figure 7]]).

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|+ Table 4: Possible Health Effects of Different Fluoride Concentrations in Drinking Water.<ref name=Dvies />

|+ {{table number|4}}Possible Health Effects of Different Fluoride Concentrations in Drinking Water.<ref name=Dvies />

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! Concentration of Fluoride (mg/l) || Possible Health Effects

! Concentration of Fluoride (mg/l) || Possible Health Effects