Trying to understand; Why do I need a root canal

Hello, please help me here!  I have a crown on one of front tooth.  It is sensitive, have been hurting a little and the color of it seems to be getting darker.  I had xrays, dentist advised me; my tooth is infected & I need a root canal. I immediately told the dentist, I refuse to get a root canal.  I have not heard anything, I mean nothing good about it.  Besides, two of my son's had a root canal and we still ended up getting that same tooth extracted.  

I am so paranoid until I don't know what to do.  I got a second opinion (doctor who originally put crown on) and was advised, either lose (get implant or partial) the tooth or root canal.  First dentist advised, they will perform root canal and replace crown to blend in with my other tooth (& I'm getting braces later).  Other dentist advised, get root canal and he will bleach tooth underneath & crown will be whiter.  What if I just take my antibiotics and see how it does from there.  Here is why I say that......

I had this same tooth xray 5 years ago and a dentist said you need a root canal.  I went and got a second opinion and that dentist say, no, you do not need a root canal, be careful with those, gave me some antibiotics & said you will be fine.  That was five years ago.  I guess I am trying to understand, why do I need a root canal.  Why?  If my molar is good, tooth infected, why a root canal.  But, the other dentist told me my tooth was dead underneath and it was totally black which is why the crown is getting darker.  

I appreciate any professional advice you can provide and thank you for reading my question.  

K

[Jerome Tsang, DDS]

Well, I am not able to see what your dentists see but it seems that both of them advise you to get a root canal.  If there is enough sound tooth structure underneath the crown, I would advise you to get a root canal and replace the crown with a more cosmetically matching crown.  The reason why I say this (without knowing your case specifically) is that I'm worried about why you need a root canal in the first place.  This blackening underneath your crown could be a cavity and doing a root canal will take you out of pain but I'm afraid that the cavity may continue to grow underneath your old crown and the tooth my break.  I would recommend removing the crown to explore underneath to see if there is a problem that may need to be addressed.

If there is a significant infection underneath the crown and into the jaw bone, antibiotics will keep the infection from spreading but it does not remove the infection.  Unfortunately, a root canal is the most likely treatment for removal.  If you do extract the tooth, then the infection will also be resolved but now you have to address the issue of a missing tooth in the front.