As Dr. B. mentioned, it is important to know what time frame is
involved with the 'infection'.  If the root canal is just being
done and antibiotics are used to clear up any residual symptoms,
this may be OK.

If the root canal has been performed months or years ago, and is
having more infection problems, I would never rush to place a
crown unless I have retreated the root canal (or had an endodontist
deal with it).  Any retreatment would include assessing the tooth
for a cracked root.

The 'fly in the ointment' comes when a tooth is in danger of splitting
or needs a crown to otherwise restore the tooth.  I would then place
a stainless steel crown (on a posterior tooth) to hold things
together while waiting for healing instead of moving straight to
a more costly restoration.

Steve

    Why do you think there is an infection--pain, swelling, drainage?  This
doesn't meet my criteria for a tooth ready for restoration--I agree.

Steve

Thank You Steve and Thank you Steve,    The fly in the ointment is that the
dentist feels no need to explain the situation clearly for someone as
uninformed as I and most others are.   We are lucky to have SMD for the
detail that may help.I better understand what is meant now (If the infection
is a result of some sligth damage in the course of the procedure done not to
the tooth but as a side effect  and the tooth is still solid?  If the
infection is cleared, the cap can be placed.   As is the case, the root
canal was just done and the dentist is waiting for the infection to clear up
to put the crown on.    So  barring any catastrophies to the root or tooth
(and me)  the dentist will proceed.   Actually, in the absence of being a
millionaire or even a mensch with lots of money, in my opinion a stainless
steel cap is as good as gold if not  seen.    Why is not white gold used .
Thank You again Steves, for the post.
In the next life, maybe I will remain childless.     One child is enough in
one family (me).    Is there hope?
Gail