Periapical lesions
Definitions & Key takeaways
Periapical lesions are abnormal growths or infections that can occur around the root tip of a tooth. Periodontitis and periapical abscess are among periapical infections. Periapical lesions can be caused by tooth decay, trauma to the tooth, or a previous dental procedure. Symptoms of periapical lesions may include tooth pain, swelling in the gums, and sensitivity to hot or cold temperatures. Treatment involves antibiotics, pus drainage if any abscess, endodontic treatment of the tooth, and if all fail, extraction of the affected tooth might be needed.
Bacterial infections of the tooth and the surrounding tissues progress rather slowly, but every step is so much more severe than the previous one.
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.
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.
But, fighting infection is a bloody affair and many of the neutrophils perish during the fight. Macroscopically, the battlefield, containing neutrophil remains, released enzymes, NETs and dead bacteria, makes up pus.
And a lot of it can accumulate, given the severity of the infection. Enzymes from the pus will irritate the surrounding tissues, creating an acute phase of apical periodontitis.
The accumulation of pus is called a periapical abscess, as it surrounds the root. This abscess can eventually form a sinus tract, which is a narrow passageway that extends from the abscess to the mouth, through which the pus can drain out.
The periapical abscess can also progress into a periapical cyst, which is when fibrous tissue and immune cells surround an area of chronic infection containing pus.
In less fortunate cases of periapical lesions on the maxillary teeth, the cyst can form a fistula to the maxillary sinus, causing a severe case of sinusitis.
If the external drainage fails to happen, and the cyst or abscess continues to grow, the lesion might progress to osteomyelitis, which is the inflammation of the underlying bone, or cellulitis, which is the inflammation of the throat.
One severe form of cellulitis is called Ludwig’s angina, where the inflammation of soft tissues is so severe, it may lead to death through suffocation.
Treatment of periapical lesions usually involves antibiotics to curb the infection. Then, an endodontic therapy is performed where the decaying pulp is removed and the abscess is drained.
The pulp space gets thoroughly cleaned and disinfected, while the tooth crown is repaired, allowing the dead tooth to continue doing its mechanical function of chewing.
Endodontic therapy has a high success rate, however, the treated tooth can sometimes reinfect and an extraction may be required.
All right, as a quick recap. Periapical lesions are inflammatory in origin, and involve apical periodontitis, which may evolve into periapical abscess or a periapical cyst.
Abscesses can drain into the mouth or cause cellulitis. Treatment involves antibiotics, pus drainage, endodontic treatment of the tooth, and failing all that, extraction of the affected tooth.
No notes for this video yet
Try adding a note below