Veneer or root canal or both for dying or dead front tooth?

Hello Lilian,I would strongly recommend getting the root canal and then a crown on this tooth.  And here is why:Just crowning the tooth will solve the color issue, but when we speak of teeth "dying," we are speaking of the nerve dying.  When nerves are dying, they often cause unpredictable severe pain.  Once they die, the remaining nerve tissue may be a source of infection that eventually leads to you having to have the tooth later root canal'ed or even removed.  In other words, your actual tooth may need to be pulled at a later date.  I would highly recommend getting both the root canal and the crown.  If you follow this advice, you will likely have that crown for at least another 20 years.  Good luck and I hope this helps. Follow me if you have more questions.Sarah Thompson, DMDReal Self 100

It is not mandatory at this stage, but better to go with rct followed by veneer / crown to stop further discoloration.
discolouration is because of dead pulp tissue. So better to clean it by rct and thn go for cosmetic procedure [veneers/crown].

The best place to start is with an evaluation by an endodontist to determine if a root canal is necessary. If there is no need for a root canal you may move forward with the veneer to mask out the color.