A periodontal pocket is a dental term indicating the presence of an abnormally deepened gingival sulcus as it contacts a tooth.

The tooth/gingiva interface

Contrary to what may be perceived by most people, the interface between a tooth and the surrounding gingival tissue is a dynamic place. The gingival tissue forms a crevice surrounding the tooth, not unlike a miniature fluid-filled moat, within which floats food debris, and both endogenous and exogenous cells and chemicals. The depth of this crevice, known as a sulcus, is in flux with microbial invasion and subsequent immune response. Located at the depth of the sulcus is the gingival attachment to the tooth, consisting of approximately 1 mm of junctional epithelium and another 1 mm of gingival fiber attachment, comprising the 2 mm of biologic width.

Pockets

The normal sulcular depth is three millimeters or less. Through much investigation and research, it has been determined that sulcular depths of three millimeters or less are either readily self-cleansible or able to be easily cleansed by an individual with the bristles of a properly utlized toothbrush. When the sulcular depth is in excess of three millimeters on a constant basis, even regular toothbrushing will be unable to properly cleanse the depths of the sulcus, allowing food debris and microbes to accumulate and pose a danger to the PDL fibers attaching the gingiva to the tooth. If allowed to remain for too long of a period of time, these microbes, together with the enzymatic particles they produce, will be able to penetrate and ultimately destroy the delicate soft tissue and periodontal attachment fibers, leading to an even further deepening of the sulcus.

Gingival pocket

If the depth of the sulcus has moved apically, or towards the root of the adjacent tooth, but has not yet breached the connective tissue fibers that connect the gingiva to the tooth, it would be termed a gingival pocket, which is completely reversible with the onset of more adequate and thorough oral hygiene practices.

Periodontal pocket

If, however, the original depth has been violated so much that the gingival fibers that initially attached the gingival tissue to the tooth have been irreversibly destroyed, the sulcus is termed a periodontal pocket. An indicator as to when a gingival pocket has proceeded to a periodontal pocket is the incidence of bleeding on probing. The localized inflammation at the depths of the sulci destroy and erode the epithelium and can elicit bleeding upon even the gentlest of manipulations.

If the destruction continues apically unabated and reached the junction of the attached gingiva and alveolar mucosa (more loosely attached oral epithelium), the pocket would thus be a violation of the mucogingival junction, and would be termed a mucogingival defect.

Pseudopockets

An increased depth is not an absolute indicator of soft tissue and periodontal fiber destruction as the base of the sulcus. If the height of the gingival tissue increases coronally without any increase in sulcular depth, a pseudopocket will form. While this may initially appear as a gingival or periodontal pocket upon measuring the depth with a periodontal probe, it is really just a change in the height rather than a change in depth. This may happen as a result of gingival inflammation or as a response to medications such as phenytoin or cyclosporin. While an pseudopocket is inherantly non-pathologic, it may easily lead to pathosis, because the increased relative depth of the sulcus is thus too deep to adequately clean with a conventional oral hygiene routine utilizing only a toothbrush and dental floss. If the drug regimen cannot be altered, scheduled gingivectomy procedures should be performed to maintain the gingival sulcus depths at or near three millimeters.

References