A dental abscess is a painful, swollen pocket of fluid that collects in or near an infected tooth.
What Causes Abscesses?
Dental abscesses usually start out as small cavities. As the decay progresses through a tooth, it reaches the nerve chamber where it triggers painful inflammation. The infection then has nowhere else to go but out the tip of the root. The pocket of pus usually then develops next to or on the tip of the tooth root.