Can you tell me all about what facts you can tell about a person from their teeth?

Lots of things: Interesting question.. Definitive identification of a body is possible through dental records and examination, genetic origins of populations can be inferred from studying size and morphology of dental remains, and behavioral patterns along with human pathology can be identified for an individual from a dental examination. Search "dental anthropology" and "forensic dentistry" for many more ideas.

Lots: We can tell quite a bit about a person from their teeth and mouth. Age of young people. People can be identified by their teeth and bite marks. Diet, habits, smoking, drug use can show up in the teeth. Many diseases show up in the mouth.