deposit soft are plaque and which harden called  tartar. plaque can be removed by proper brushing but tartar can be removed by proper scaling in dental office. if not removed the cause recession I.e exposure of root of teeth tat may lead to sensitivity. that scaling why check and scaling is recommended 6 month to year.

due to the white deposit whatever gums you have seen gone behind wil progress further if you let it remajn.. it has caused an irreversible damage which can be only stopped by removing it.. hence cleaning by dentist is required  alongwith proper oral hygiene measures to prevent it from coming back.. after the initial cleaning procedure is done the gums atleast wont recede further and can be grown back in certain conditions.. do go with the cleaning protocol as soon as possible :)