Bad wisdom teeth do not cause oral cancers.
Some people come to it from the
HPV virus, tobacco use, heavy alcohol consumption, some people have no identifiable lifestyle risk factors at all, and it is assumed that genetics played a role in their coming to the disease.
You could have them test the tissue in pathology for HPV16 the virus, (if they won't or do not have the ability to, there is a link on the OCF main site
HPV page to the Johns Hopkins lab that will) since they have to keep that sample 7 years by law, and you have eliminated tobacco and alcohol.