How rare is it for a tooth abcess to spread to the brain?

Quite Rare: But a dental abscess can easily spread into your bloodstream if not properly addressed. Once in the bloodstream it can travel to other parts of your body and cause a host of issues.

Rare: Rare, but instances hav3 been reported. Any infection, whether an abscessed tooth or an infected cut on your hand, can travel through the blood stream to other organ systems causing severe and even life-threatening problems. Please do not play Russian Roulette. See your Dentist as soon as possible for appropriate treatment.