How common is necrotic fascittis or skin eating bacteria after tooth extractions?

Not common: It is very unlikely you will develop any sort of skin eating bacteria after surgery. In 15 years of practice I have never had a patient have anything like this happen. It's very rare and If you are concerned please visit your treating doctor to evaluate your extraction sites. Hope this helps!

Very rare disease: It can be fatal if not treated promptly.

Almost impossible: In over 40 years of practice I have never seen or heard of this happening. One can develop an infection after an extraction and only if not properly monitored and treated can it become more serious. See a qualified dentist and follow instructions and everything should be fine and without ANY serious complications.

Not common: Rarely seen. You may be thinking of ONJ -- osteonecrosis of the jaw. This is rare as well and associated with the use of osteoporosis medications typically given IV (Actonel, foxamax,etc. ) (bisphosphonates). Unless you have been on these or are currently on them there is little risk with extractions. Ask your Oral Surgeon about this. Good Luck.