Sometimes due to various reasons there can be a secondary tooth decay
below the filling in the teeth that were previously treated and filled. An X-Ray will reveal the exact spread of the decay. If the decay has not reached pulp then the treatment would be to take out the previous filling, remove the further decayed portion of the tooth and place a new filling. If the X-Ray of your tooth shows the infection
involving the pulp then Root Canal Treatment
needs to be done. As you have mentioned that you are not able to chew food at all, I suspect that pulp may have got involved and RCT may be required for you. The total cost may start from ₹2000 and go upwards depending on teeth, dentist
, location, crown etc.