You should go to an endodontist and have them evaluate the root canal. They are experts in root canals, general dentists are not. If an endo did the root canal, go to another for a second opinion. If the root canal is redone make sure that they do not use sargenti paste (formaldehyde) on it....NEVER NEVER NEVER.
rootcanal is already done by a special dental sugeon . i dunt know wht is sargentic paste????