Periapical lesions

Bacterial infections of the tooth and the surrounding tissues progress rather slowly, but every step is so much more severe than the previous one.

Cariogenic bacteria will first tear enamel down.

Then they’ll bore through dentin. When they or their toxic waste get into the pulp, pulpitis occurs.

Without immediate treatment, pulpitis can cause irreversible damage and require a root canal.

If no treatment is performed, the pulp will eventually die off through necrosis.

At that point, the tooth is considered dead, and in essence, it becomes a staging area for bacteria to spread further.

Our immune system will, at that point, try to stage a defense around the apices of the dental root.

We call that “battlefield” apical periodontitis, which is one of the periapical lesions.

The primary form of defense our body has against infection is the polymorphonuclear leukocyte, also known as the neutrophil.

It is the finest soldier serving our body, and its task is to locate and destroy microbes that intrude into the body, wherever that might be. This is usually a very effective force, and most of the times sufficient.

When an infection occurs, neutrophils will mobilize in huge numbers, head to the site of infection, and leave the circulatory system, searching for bacteria to destroy.

They achieve this through three methods.

First is degranulation, where neutrophils release a bunch of granules containing various enzymes, that hurt bacteria.

Then, they will use neutrophil extracellular traps, or NETs, to immobilize the wounded bacteria.

These are actually nets, made out of neutrophil DNA!

Finally, neutrophils will then gobble up the bacteria through phagocytosis as a final means of its destruction.

All of this works really well, most of the time.