Broomhilda...sorry to but in....but has your dentist suggested a strong regime of anti-b's prior to the surgery. With your history and background this would be pretty much S.O.P. and could prove to be very important. If he has....great, no problem...... if he has not, then you may want to question that.
My wife is a hygentist and she says many complications from oral surgery come on because folks like us (compromised immune systems) ...or people who have had recent surgeries..don't know or aren't told that they should be on anti-b's prior to and during the dental work. Her office even suggests it if you are just coming in for a deep cleaning and have the issues I cited.
A dental infection is nothing to mess with...it is so close to the brain and heart that infection into those areas is very common after major dental work.