I've done root canal a year back. All of a sudden it had started to pain again. And a severe pain that goes upto my ear. Dentist told me, i might have eaten something hard bcos of which my tooth must have fractured & have got infection. And I am supposed to take Antibiotics. I have a doubt here, if the root canal process is about removing all dead nerves & pulp and sealing it, how can I develop infection and also if there is no connecting nerves, how will antibiotic work?