Cavities occur mainly on the biting surfaces of the teeth or other places like in between the teeth or at the junctions of the teeth n the gums. These appear as dark spots initially and start becoming bigger. These might be associated with food stagnation or if they are deep then with sensitivity as well. Cavities can be avoided with proper brushing twice a a day. Rinsing your mouth after any intake. Visit to a dentist once every six months .

hello the early signs of a cavity would be sensitivity to hot or cold things and food lodgement in that tooth only way to avoid cavities from developing is to use a fluoride based toothpaste and go  once a year for dental consult if there r any small cavities th ey can be detected for you at an early stage