Third molars: pericoronitis arises from a space nobody can clean

The partially erupted third molar creates an anatomical situation found nowhere else in the mouth, which is why pericoronitis has an almost exclusive site.

When the tooth erupts only partly, a flap of gum remains, the operculum, covering part of the crown.

Beneath that operculum a space forms which communicates with the mouth but is inaccessible to a brush and has no self-cleansing. Bacteria and food debris enter, and nothing leaves.

It is an anaerobic environment with constant substrate, that is to say the ideal conditions for a pathogenic flora to develop.

Acute pericoronitis presents with intense local pain, swelling of the operculum, difficulty swallowing and often trismus, meaning limited mouth opening.

Trismus is a sign deserving attention because it indicates involvement of the deeper tissues, and together with fever and lymphadenopathy it defines a picture requiring prompt intervention.

A frequent aggravating factor is trauma to the operculum from the opposing upper tooth, which with every closure compresses an already inflamed tissue and feeds the process.

In the acute phase local management involves irrigation of the sub-operculum space with an antiseptic solution, which removes stagnant material and reduces the bacterial load.

Antibiotics are reserved for cases with systemic involvement or marked trismus, not for localised pericoronitis which responds to local management.

Advice to the patient for the acute phase is simple and should be given so that it can be followed: frequent warm rinses, gentle hygiene of the area with a soft brush, and food that avoids debris becoming wedged.

It should be said plainly that pericoronitis recurs while the anatomical situation persists, because that space continues to exist.

The decision on extraction belongs to the surgeon and rests on the tooth's position, available space, number of episodes and anatomical relationships. The hygienist's role is to document the episodes and refer.

In summary: the operculum creates a space that cannot be cleaned, acute pericoronitis brings pain, swelling and often trismus, trauma from the opposing tooth feeds the process, local irrigation is the basic management, and episodes recur while the anatomy stays unchanged.