Why do teeth undergo decay by eating sweets regularly?

Explanation

Our teeth are coated with a white enamel which is `Ca_(5)(PO_(4))_(3)(OH)`, an insoluble compond containing calcium. It is believed to exist in a state of equilibrium as follows:
`Ca_(5)(PO_(4))_(3)(OH)(s) ltimplies 5Ca^(2+) + 3PO_(4)^(3-) + OH^(-)`
When we donot brush our teech properly after eating sweets, then these stick to our teeth and gums. The sugar present in them slowly gets fermented to produce `H^(+)` ions which combine with `OH^(-)` ions to form `H_(2)O`. Therefore, the equilibrium gets shifted to the right which means that the enamel from the teeth will slowly get removed and they will therefore, decay.