What is tooth enamel chemically ? State the conditions when it starts corroding. What happens when food particles left in the mouth after eating degrade ? Why do doctors suggest use of tooth power/tooth paste to prevent tooth decay ?

Explanation

(i) The tooth enamel is chemically calcium phosphate with the formula `Ca_(3)(PO_(4))_(2).` It is quite hard.
(ii The enamel starts corroding when the pH inside our mouth falls below 5.5 because the saliva present in the mouth is acidic.
(iii)The bacteria present in hte mouth break down the food particles into acids which damage our teeth by corroding them.
(iv) The contents of the tooth paste are of basic nature. They neutralise the excess of acid present. As a result, the corrosion of enamel and decay of teeth are checked.
That is why doctors suggest use of tooth powder/tooth paste to check or pravent toth decay.