It depends what they do. If they hardly need to do anything then I'd ride same day. If they spent 15mins hacking away at teeth then I'd wait until day after...
My dentist came out yesterday, I asked the same question, and his response was the teeth are along way from the heart... in other words riding the same day is no problem!
My boy had over an hrs worth of work done last week and the vet/dentist said not to ride him that day and then just gently the next, then back to normal.
if your useing geraint hughs then he;s coming out to see me on wednesday as well!
he normaly says you can ride the next day if you dont have anything major done (like a tooth extraction)