Crowned Tooth with Emax and Its Highly Sensitive, Please Advise?

Sorry to hear about the problems you are experiencing with one of the teeth.  Placing a crown on a tooth can be a fairly traumatic experience for that tooth and could force an unplanned root canal procedure.  In addition, it sounds like you had a lot of new veneers/crowns and your bite may be struggling to adjust.  You are wise to look at all options before committing to a root canal.  Check with your dentist to see if he evaluated your bite/occlusion in the area where you experiencing pain.    Do you have a history of clenching/grinding (bruxism) at night?  Even if you do not, with so many new teeth, your musculature may be trying to adjust to your new bite and you might be clenching/grinding.  If you are not wearing the correct type of night guard for your problem, your dentist may be able to fit you with a temporary anterior style guard to rule out bruxism as a culprit.

There are other factors at play here.  I am assuming the tooth in question did not have sensitivity/pain prior to receiving a crown.  Is the pain you are experiencing getting better/worse/stable?  What is the level of discomfort you are experiencing?Ultimately, you and your dentist know your case/history best. If you feel comfortable that your dentist has addressed all your questions and you are both comfortable that a root canal is the only option remaining, then that might be the price you have to pay.  Otherwise, you may wish to seek a second opinion from another dentist.

Anytime a procedure is done to a tooth there is a possibility the nerve may be damaged.  Nerves in teeth have a poor healing ability and we can never predict how much trauma a tooth can endure without the nerve becoming a problem.  Before a root canal is done be sure the bite is not heavy on the new crown as that can also cause symptoms you are describing.