relating to the maxilla (upper jawbone) and the face.

Maxillofacial surgery is a specialization of medicine and/or dentistry that focuses on problems around the mouth, jaw, midface and neck.
Anatomical limits and skills differ country-to-country. In some countries doctors attend medical school, dental school and than an additional residency. In other countries they attend either dental (calling them oral surgeons quite often) or medical school.