An abscessed tooth can be painful and traumatic. Your face may swell and your tooth and the surrounding gum tissue will likely be as painful as the tooth itself. What is a tooth abscess? Bluntly, it's a pocket of pus caused by a bacterial infection. The abscess can be at the tip of the root, deep inside the tooth, or in the gum surrounding the affected tooth. An abscessed tooth is a dental emergency, and most dentists will see you as quickly as possible -- usually on the day that you call them. That's because an untreated tooth abscess can actually lead to some pretty serious complications, some of which can be life-threatening!