New crown - swollen gum

[vhosk]

I recently had a crown on a rear bottom tooth.  Dentist put in temp filling for few week - extremely painful for few days, gum went white underneath and lots of pain in the jaw / gum but no pain in tooth (prob due to LT problem with TMJ).

I returned to dentist for crown prep and she said that due to this problem with temp filling and fact that hole went close to root cavity I may need RCT.  Since I was not in pain and there was nothing on x-ray, she said she would put temp crown on and when perm crown came in she would put it on with temp cement for few months to see if there was a problem.  The temp crown was fine for a few days, except the bite was too high.  After a few days a bit broke off and after that there was a swishy feeling whenever I bit down but no pain.  I explained this to the dentist when I went for the perm crown.

Perm crown was put in and i found it much bigger than original tooth (level on the outside but sticks out on inside by about 1/2 a tooth) which is uncomfortable and a lot higher, so is the first tooth hit everytime I bite down.  After a few days I noticed  swollen lump on gum under crown but still no pain. Went to dentist to file it down, she had a quick look and said I had an abscess, may need RCT and gave me antibiotics.  She said that even though she had suggested temp cement because I was in no pain she had actually used perm cement so would have to drill through.

Gum still swollen and felt wobbly, so saw dentist again.  She took another x-ray which showed infection in the gum rather than the root canal so gave me more antibiotics but hasn't improved things so says I now need RCT.

Is is an abscess / RCT if I have no pain and no sensitivity to hot / cold?
If I need RCT does ite it worse now that the crown is on?

[Jerome Tsang, DDS]

A dull patch?  I'm not familiar with that term so I'm not sure what she is saying.

If a root canal is performed, it depends on whats going on underneath.  In this case, since the crown was done recently, I'd feel it would be fine to leave the crown and do a root canal through it instead of replacing the crown.  It should be structurally fine after a root canal as they'll do a filling to replace the missing tooth and crown structure.

[vhosk]

Thanks for your help.

X-ray shows no infection in roots but a dull patch (which she says is infection)  between the two root canals.  Still no pain just feels strange and lump on gum.  Antibiotics have had no effect either time.

If root canal as effective through a crown (I have long roots) and does it weaken the crown or reduce its lifespan if it is drilled then filled.

[Jerome Tsang, DDS]

Yes, you can still have the need for a root canal with no sensitivity to hot or cold.  This occurs when the nerve inside the tooth is completely dead, resulting in no sensation at all to hot or cold but you can still have pain in the jawbone as the infection spreads there from the pulp chamber

You can perform a root canal through a crown.  You just have to make sure you fill the crown back up with a filling material to prevent any leakage of the crown.  

Not sure why your dentist decided to change her mind about the cement situation though but if its permanently cemented, then there's no way to re-do the crown unless you cut it off again and make a brand new one.  I have no problem with a permanent cementation but just wondering why she changed her mind.