Kinda dumb question - dental work and working out?

I had a root canal yesterday, fun fun!  Well after the dental fun, I mentioned to a friend that it was speedwork day and that I was going to run later.  She is training for a marathon and said that she had a root canal a couple of months ago and did a 5-miler that night and an 11-miler a couple of days later and each night was in excruciating pain.  She called her dentist and he told her that he didn't recommend exercise after that type of procedure because it gets the blood pumping and can cause that pain.

Have you heard this?  I ended up walking on the dreadmill instead, but I was hoping to hit my lunchtime spin class today and swim tonight.  I also have my long run tomorrow night.  I hate missing workouts!!!