Did the dentist use a dental drill to clear out old decayed bone or the less invasive procedure described by Dr Tennant below.
To fix it, they make a tiny slit on the side of the gum. They pop down into that area, clean out the muck and inject that with ozone. The bone is like a sponge, and there are a lot of places for bugs to hide. The ozone, because it’s a gas, will kill any bug and sterilize it. Then they draw some blood out of the arm, spin it down, and pull out the fibrin that contains all the chemicals hat tell bone to heal, stuff it down into that hole and it heals like magic.