Just returned from Dana-Farber (CCC) in Boston for dental consult in H & N cancer department. This dentist works almost exclusively with oral cancer patients. I will write a more detailed summary later, but regarding wisdom teeth, which is my husband's immediate problem, this was her advice:

Current guideline is that heathy teeth are NOT removed prior to rad. The decision regarding wisdom teeth is less clear. If a wisdom tooth has never been a problem in the past, it is usually left alone. If there have been flare-ups in the past, it should probably be removed before tx.

As Cheryl pointed out, extractions prior to rad, run the risk of delaying cancer treatment, especially if complications develop. This dentist sees 3-4 patients a week with infected/damaged teeth post rad. Not just wisdom teeth, but all teeth (especially molars) are at risk.