At its base definition, apex means the highest part of something. In the dental world, it’s referring to the very end of a root, where it connects to the pulp and is able to get blood and nutrients from the body. As a general rule, if you are hearing “tooth apex” from a dentist, chances are a root canal will be involved. If you hear the term “Open Apex” it is generally referring to a gap between the apex of a tooth and the jaw. It can heal itself but is often lightly assisted to make sure that the tooth does not die (become necrotic).
To understand more fully, a tooth is made up of about 7 different sections, being further broken down into the crown (what can be seen above the gums), and the root (what is visually hidden). The apex is the very bottom part of the root that has a nerve ending that attaches to the nerves in the jaw.’’
A dental abscess occurs at the apex of the tooth. A sack (dental cyst) appears that can put pressure on the nerves, and sometimes block the nerve. This is known as a blocked canal, which can cause your tooth to die from getting a lack of nutrients. Abscesses are often caused by bigger issues, such as an infected pulp. Infected pulps can be very damaging to the body and can sometimes even kill you if the infection spreads to other, more vital parts of the body. In this case, they will put you on antibiotics to treat the infection, and surgically remove the inflamed section of the tooth.
When the tooth cannot be saved because of apex damage, typically from a cyst, your dentist may perform a root canal. When you have a root canal, the dentist goes into the tooth and removes the nerve and infected pulp in order to save the tooth (even though it is no longer “alive”). This is typically needed to prevent an infection from spreading.