Hello sir Hope you are doing well The problem you shared in that case if you are pain or discomfort those teeth then you decayed may have involve third layer of tooth which is giving you pain so consult near by dentist and get the exact suction of your teeth and you can take an action on time before the cause you lot of pain

Hello sir,          Hope you are staying safe and well. The problem you shared is dental caries or decayed tooth. Can you differentiate whether the tooth is paining or feeling so sensitive on drinking or eating?Do you have any sharp pain extending till jaw,ear and head? Pain during night?

Black discolouration of teeth can be due to decay or stains...so first we need to determine the cause(share xray or photo if you have) ...also if it's hurting you,  than chances are that it's mostly decay...There is nothing to reverse cavity, u can either prevent it or  if it  happens,  treat it to the earliest to prevent further damage and pain.

Hello, First of all we need to be sure that it’s a cavity. Secondly there’s nothing to reverse the cavity, only General treatment like filling which could further prevent the risk. Kindly book a consultancy to be sure of the cause of tooth pain and then we can plan the treatment accordingly.

Hello dear Please be calm See it can be stains or caries which both require seperate treatment.i suggest you to please share pic for confirmation of diagnosis.fir further details you can consult me Thanks