(a)Which chemical substances is present as enamel on the surface of the teeth ? (b)Traces of fluoride ions (F^-) in drinking water (about 1 ppm) greatly reduce the incidence dental cavities (tooth decay ) . What is the reason for reduction in cavities ?

(a)Which chemical substances is present as enamel on the surface of th

1.	(a)Which chemical substances is present as enamel on the surface of the teeth ? (b)Traces of fluoride ions (F^-) in drinking water (about 1 ppm) greatly reduce the incidence dental cavities (tooth decay ) . What is the reason for reduction in cavities ?
Answer» Solution :(a)The chemical substance present as enamel on the surface of the TEETH is `3 Ca_3(PO_4)_2 . Ca(OH)_2` (b)The fluoride ions `(F^-)` convert to enamel to much harder `3Ca_3(PO_4)_2. CaF_2` . Hence, the INCIDENCE cavities is GREATLY reduced.