For gingivectomy, how do doctors numb you?

Local anesthetic. We use a local anesthetic in a needle syringe near the areas we are doing surgery on. We may also give you what we call a block injection which will numb a larger area with a single needle stick. Very quick and very easy and works wonders.
Comfort zone. The appropriate anesthesia depends on the complexity of the dental treatment and your own comfort zone. With the profound local anesthesia and IV sedation you will have no recall of the events of the gingivectomy surgery or experience any pain. Good luck.