Question

how holes or cavities formed in teeth

Answer 1

It's due to our negligence.By eating soo many chocolates which can spoil the teeth,by not maintaining the teeth properly,by not brushing properly,by not caring the teeth .These all can cause bacterial formation in the teeth ,which later causes holes or cavities in the teeth.

Answer 2

The holes and cavity in teeth are formed by the bacterial action on food particles that release acid that decay that tooth and cause cavity .For protection, we need to brush two times daily in a day