Ok....This is why bloodwork is done:
It checks blood glucose levels, liver and kidney function, full CBC (checking for anemia and clotting levels and any hidden infections).
We do not do dentals at our hospital without having bloodwork done in the past 6m (unless 2 or under). All dentals have iv fluids and during the anesthetic we have them fully monitored with blood pressure, heart rate and respiration being monitored. Older patients we may do EKGs on during the anesthetic.
BTW.....a complete dental cannot be done on an awake patient. Much of the cleaning is done under the gumline. Plus if there are any issues dental xrays may be done which again cannot be done on an awake patient. Oh and most places that do preop work they will likely be more on top of monitoring too.
I couldn't even hazard a guess on the number dentals I have done in the past 14y and I completely recommend full workup before hand.