Hi, It would be great if you send me a pic of your front tooth.. There are toothpaste which can reverse the decay but that depends on how much has the caries progressed..

Get your decayed tooth restored by tooth colored filling material to remove the black dot.black dot cannot be reversed. You can consult through this for further details.

See once cavity is formed,it cannot be reversed it will keep on decaying with time ….. The only solution is to get the decayed part removed and filled it with a right shade of composite filling as it’s your front tooth so aesthetically it should look same like your natural teeth. Secondly,about changes it’s best to get the decayed part removed as soon possible as less portion of tooth be removed and restored by composite. If you delayed it, cavity keep growing inside tooth structure with time and it will just damage more of your natural tooth structure. Don’t avoid it just so you don’t want to make change cause how much it’s damaging your tooth structure could result in Root Canal Treatment which is not required if you take action and treat it at right time. Take good care of your teeth at right time. :)