Hi No need to worry...It is not oral cancer....That blackish patch may be due to traumatic bite And the RCT treated teeth may get reinfected... Complete clinical and x ray investigation of RCT treated teeth has been done... If it is reinfected then you need to go for Re root canals treatment of the teeth

Hey, Dont jump to Oral Cancer. There is a very very rare chance of that. So dont worry, the black patch could be a cheek bite or something else. You need to add it with other symptoms you have and see a dentist for the same. Also the infection that you have got in the teeth might not be due to RCT treatment failure, but it could be due to infection under the crown caused by food impaction. So, before worrying yourself to big diagnoses, just get a Dental Consult.

Qa

Ok. So is there any burning sensation associated? How well can u tolerate spicy food?  Also is the spot a new development  and does it heal and go and then again come back. Regarding your teeth with rct, it is possible that it is re infected and a re rct is required.