The Periodontal Pocket

Definition Periodontal pocket is defined as a pathologic deepening of the gingival sulcus.

Classification Based on the course of the pocket 2. Based on the attachment of junctional epithelium 3. Based on the type of pocket wall

I. Based on the course of the pocket – A. Simple pocket B. Compound pocket C. Complex pocket

II. Based on the attachment of junctional epithelium – Gingival pocket(Pseudopocket) – Formed by enlargement of the gingiva without destruction of the underlying periodontal tissues. The sulcus is deepened by the increase in bulk of the gingiva.

B. Periodontal pocket(True pocket) – Occurs due to destruction of the supporting periodontal tissues Deepening leads to destruction and loosening and exfoliation of the tooth

Periodontal pockets are further classified into – Suprabony pocket (Supra crestal or Supraalveolar) - Base of pocket is coronal to the crest of the alveolar bone Intrabony pocket (Infrabony or Subcrestal or Intraalveolar) - Base of pocket is apical to the crest of the alveolar bone Suprabony pocket Intrabony pocket

Difference between Suprabony and Infrabony Pockets Suprabony Pocket Infrabony Pocket Base of pocket is coronal to the crest of the alveolar bone Base of pocket is apical to the crest of the alveolar bone Bone destruction - horizontal Bone destruction – vertical / angular Transeptal fibers restored after disease are arranged horizontally Transeptal fibers restored after disease are arranged obliquely On the facial & lingual surfaces, PDL fibers beneath the pocket follow a horizontal – oblique pattern On the facial & lingual surfaces, PDL fibers beneath the pocket follow an angular pattern

III. Based on the type of pocket wall - Edematous - Fibrous

Clinical features of Periodontal Pocket Clinical signs - Gingival bleeding Bluish red , thickened marginal gingiva Suppuration Tooth mobility Diastema formation Symptoms - Localized pain – (pain deep in the bone)

Clinical and Histopathologic Features of the Periodontal Pocket Clinical Features Histopathologic Features Bluish red color Smooth , shiny surface Pitting on pressure Circulatory stagnation Atrophy of epithelium, edema Edema, degeneration of tissues Pink, firm pocket wall Fibrotic changes Bleeding Due to increased vascularity Thinning and degeneration of epithelium Engorged blood vessels When probed, inner aspect of pocket wall is painful Due to ulceration of inner aspect of pocket wall Discharge of pus on digital pressure Due to suppurative inflammation of inner wall

Pathogenesis of Periodontal Pocket Initial lesion in development of periodontitis Inflammation of the gingiva (due to bacterial challenge)

Pocket formation - Starts as an inflammatory change in the connective tissue wall of the gingival sulcus The exudate causes degeneration of surrounding connective tissue(gingival fibers) Apical to the junctional epithelium – collagen fibers are destroyed The area is occupied by inflammatory cells

Mechanism of Collagen Loss – Collagenases – secreted by fibroblasts, PMNs, macrophages Fibroblasts – phagocytize collagen fibers Once collagen is destroyed – apical cells of junctional epithelium proliferate along the root The coronal portion of junctional epithelium detaches from the root and PMNs invade

Thus the sulcus bottom shifts apically Formation of Pocket TOOTH Gingival sulcus/ crevice Gingival Epithelium Thus the sulcus bottom shifts apically The initial deepening of the pocket occurs between junctional epithelium and root Sulcular Epithelium Junctional Epithelium

Histopathology of Pocket Formation Soft Tissue Wall Changes – Connective tissue is edematous, densely infiltrated with inflammatory cells( Plasma cells) Blood vessels-engorged, numerous, dilated C.T shows degeneration and foci of necrosis Proliferation of new capillaries, fibroblasts,collagen fibers Junctional epithelium - marked variations in the length, width and thickness are seen.(50-100µm)

Bacterial Invasion of Pocket Porphyromonas gingivalis Prevotella intermedia Actinobacillus actinomycetemcomitans Bacteria invade the intercellular spaces under the exfoliating epithelial cells

Microtopography of the pocket wall Areas of quiescence – shedding of cells seen Areas of bacterial accumulation - in the intercellular spaces Areas of emergence of leukocytes - in the intercellular spaces Areas of leukocyte bacterial interaction Areas of intense epithelial desquamation Areas of ulceration - exposure of connective tissue Areas of hemorrhage – numerous erythrocytes

Periodontal pockets as healing lesions Periodontal pockets are chronic inflammatory lesions which undergo repair The condition of the soft tissue wall of the periodontal pocket results from the interplay of destructive and constructive tissue changes. The balance between the destructive and constructive changes determines the clinical features of the pocket wall. Based on this there is either formation of edematous or fibrotic pocket wall.

Pocket contents Microorganisms and their products Gingival fluid, food remnants Desquamated epithelial cells Leukocytes Significance of pus formation It is only a secondary sign It reflects the nature of inflammatory changes in the pocket wall Not an indication of depth of the pocket or severity of destruction

Root surface changes of Pocket Cause pain Recurrence of infection Complicate the treatment

Deepening of the pocket Collagen fibers in the cementum degenerate Exposure of cementum to oral environment Penetration and growth of bacteria Areas of necrotic cementum formation

Changes in Root Structural changes in Root Chemical changes in Root Cytotoxic changes in Root

Structural changes in Root: 1. Presence of pathological granules 2 Structural changes in Root: 1.Presence of pathological granules 2.Areas of increased mineralization - Highly mineralized layer increases the tooth resistance to decay 3. Areas of demineralization - Commonly related to root caries, dominant organism is A.viscosus

Chemical changes - Increased calcium, phosphorous, magnesium, fluoride Cytotoxic changes -The diseased root fragments - Decrease fibroblast attachment - Induce an inflammatory response

Surface morphology of the tooth wall of periodontal pocket 1.Cementum covered by calculus 2. Attached plaque 3. The zone of unattached plaque 4. The zone of junctional epithelial attachment 5. Zone of semi destroyed connective tissue fibers Zones 3,4 &5 form the plaque free zone Width of the plaque free zone depends on the type of tooth and the depth of pocket.

Periodontal disease activity Periodontal pockets progress through periods of quiescence and exacerbation. The periods of quiescence and exacerbation are also known as periods of inactivity and activity.

Pulpal changes associated with periodontal pocket Spread of infection from periodontal pocket cause pathological changes in the pulp leading to painfull symptoms . Involvement of the pulp may occur by spread of infection through apical foramen or by lateral canals in the root.

Relationship of attachment loss and bone loss to pocket depth Pocket formation causes loss of attachment of the gingiva and denudation of the root surface. The severity of attachment loss does not correlate with the depth of the pocket

Different pocket depths with the same amount of attachment loss

Periodontal Abscess It is a localized purulent inflammation in the periodontal tissues. Also called as - Lateral abscess, Parietal abscess Abscesses localized in the gingiva, due to injury, which does not involve the supporting tissues is called as Gingival Abscess

Periodontal Abscess

Microscopic features of Periodontal Abscess Localized accumulation of PMNs in periodontal pocket wall PMNs liberate enzymes digest tissue & cells pus (present in centre of abscess) Overlying epithelium exhibits intravascular & extracellular edema Invasion of leukocytes Chronic Abscess – when purulent content drains through a fistula into outer gingival surface

Periodontal Cyst Uncommon Lesion that produces a localized destruction of the periodontal tissues along the lateral root surface Seen in mandibular canine – premolar region

Microscopic features of Periodontal Cyst The cystic lining contains - - Loosely arranged, non – keratinized, thickened, proliferating epithelium - Non – keratinized, thin epithelium

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