Antibiotics aren't always given, but often may be if the area around the tooth and the tooth are badly infected especially if the pain caused by it makes it difficult or impossible to do a root canal. Sometimes the nerve is so infected, that the local pain-killing injections have little or no effect on reducing the pain, which would make the procedure very painful. If the infection creates an abcess or has spread beyond that point, then antibiotics may be necessary for your health and wellbeing because the infections can eventually be very serious.
Penicillian is often given. I've had a type of cephlasporin as well.
1st root canal: I had to have penicillian so they could do the work. Closed tooth back up, took medicine, reopened tooth and cleaned it out a week later, much, much better in terms of pain.
2nd root canal(one from HELL): went through penicillian and cephlasporin. Both cleared up some of the outer facial infection but left the tooth area still quite painful in one root of the three roots.(later I learned that root had a tiny, undiscovered canal which probably worsened the infection) had to have sedation to get this one fixed due to the pain.
3rd re-treatment of above tooth, due to undiscovered canal. treated with augmentum because pain was in sinus area and initially believed to be sinus infection. No effect so I had to do retreatment. During retreatment, endo. put me on penicillian when tooth 'blew' up after first part of procedure--pain, swelling, penicillian helped a lot in that case.
it's a case by case thing in my experience. Ask your dentist or endo about antibiotics and whether you need them and their reasoning. They have side effects so prepare for those, if you do need to take them.
[This message has been edited by butterflycollective (edited 08-24-2003).]