Periodontal Periodontal PathologyPathology

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Dr. Marcel HallareDr. Marcel Hallare

The gingival tissue is constantly subjected The gingival tissue is constantly subjected to mechanical and bacterial aggressionsto mechanical and bacterial aggressions

Resistance to these actions is provided Resistance to these actions is provided by the saliva, the epithelial surface, and by the saliva, the epithelial surface, and the initial stages of the inflammatory the initial stages of the inflammatory responseresponse

The pathologic changes that accompany The pathologic changes that accompany gingivitis are associated with the gingivitis are associated with the presence of oral microorganisms in the presence of oral microorganisms in the gingival sulcusgingival sulcus

These microorganisms are capable of These microorganisms are capable of synthesizing harmful products that cause synthesizing harmful products that cause damage to epithelial and connective damage to epithelial and connective tissue cells, as well as to intercellular tissue cells, as well as to intercellular constituents, e.g., collagen, ground constituents, e.g., collagen, ground substance, and glycocalyx (cell coat)substance, and glycocalyx (cell coat)The resulting widening of the spaces The resulting widening of the spaces between the junctional epithelium cells between the junctional epithelium cells during early gingivitis may permit injurious during early gingivitis may permit injurious agents derived from bacteria themselves, agents derived from bacteria themselves, to gain access to the connective tissue to gain access to the connective tissue

Stage I GingivitisStage I Gingivitis

Vascular changes have been described Vascular changes have been described as the first response to initial gingival as the first response to initial gingival inflammationinflammation

Histologically, Stage I gingivitis shows Histologically, Stage I gingivitis shows some classic features of acute some classic features of acute inflammation in the connective tissue inflammation in the connective tissue beneath the junctional epithelium beneath the junctional epithelium

Changes in blood vessel morphologic Changes in blood vessel morphologic features, such as widening of small features, such as widening of small capillaries or venules, and adherence of capillaries or venules, and adherence of neutrophils to cell walls, occur within 1 week neutrophils to cell walls, occur within 1 week and sometimes as early as 2 days after and sometimes as early as 2 days after plaque has been allowed to accumulateplaque has been allowed to accumulateLeukocytes, mainly polymorphonuclear Leukocytes, mainly polymorphonuclear neutrophils (PMNs), leave the capillaries by neutrophils (PMNs), leave the capillaries by migrating through the wallsmigrating through the wallsThey can be seen in increased quantities in They can be seen in increased quantities in the connective tissue, the junctional the connective tissue, the junctional epithelium, and the gingival sulcusepithelium, and the gingival sulcus

HOST RESPONSEHOST RESPONSE ACUTE BACTERIAL CHALLENGE PHASE: EPITHELIUM AND ACUTE BACTERIAL CHALLENGE PHASE: EPITHELIUM AND

VASCULAR ELEMENTS RESPONDS TO CHALLENGEVASCULAR ELEMENTS RESPONDS TO CHALLENGE

Several microorganisms that have been Several microorganisms that have been associated with gingival inflammation and associated with gingival inflammation and periodontitis, such as periodontitis, such as Treponema Treponema denticola, Actinomyces viscosus, denticola, Actinomyces viscosus, andand Bacteriodes melaninogenicus,Bacteriodes melaninogenicus, have been have been shown to promote neutrophil chemotaxis shown to promote neutrophil chemotaxis and vascular exudationand vascular exudationSubtle changes can also be detected in Subtle changes can also be detected in the junctional epithelium and perivascular the junctional epithelium and perivascular connective tissue at this early stageconnective tissue at this early stageLymphocytes soon begin to accumulateLymphocytes soon begin to accumulate

The increase in the migration of leukocytes The increase in the migration of leukocytes and their accumulation within the gingival and their accumulation within the gingival sulcus can be correlated with an increase in sulcus can be correlated with an increase in the flow of gingival fluid into the sulcusthe flow of gingival fluid into the sulcus

Page & Schroeder called this stage the Page & Schroeder called this stage the initial initial lesion lesion

Classic vasculitis of vessels subjacent to the Classic vasculitis of vessels subjacent to the junctional epithelium and gingival sulcus; junctional epithelium and gingival sulcus; presence of serum proteins, especially fibrin, presence of serum proteins, especially fibrin, extracellularly; alteration of the most coronal extracellularly; alteration of the most coronal portion of the junctional epithelium; and loss portion of the junctional epithelium; and loss of perivascular collagenof perivascular collagen

The nature and character of the host The nature and character of the host response determines whether this initial response determines whether this initial lesion resolves rapidly, with the restoration lesion resolves rapidly, with the restoration of the tissue to a normal state, or evolve of the tissue to a normal state, or evolve into a chronic inflammatory lesioninto a chronic inflammatory lesion

If the latter occurs, an infiltrate of If the latter occurs, an infiltrate of macrophages and lymphoid cells appear macrophages and lymphoid cells appear within a few dayswithin a few days

Stage II GingivitisStage II Gingivitis

Clinical signs of erythema may appear, Clinical signs of erythema may appear, mainly owing to the proliferation of mainly owing to the proliferation of capillaries and increased formation of capillaries and increased formation of capillary loops between rete pegs or capillary loops between rete pegs or ridgesridges

Bleeding on probing may be evidentBleeding on probing may be evident

Page & Schroeder call this stage the Page & Schroeder call this stage the early lesionearly lesion

Histologic examination of the gingiva Histologic examination of the gingiva reveals a leukocyte infiltration in the reveals a leukocyte infiltration in the connective tissue beneath the junctional connective tissue beneath the junctional epithelium, consisting of mainly epithelium, consisting of mainly lymphocytes (75%) but also composed of lymphocytes (75%) but also composed of some migrating neutrophils, as well as some migrating neutrophils, as well as macrophages, plasma cells, and mast cells macrophages, plasma cells, and mast cells

There is an intensified overall inflammatory There is an intensified overall inflammatory cell response compared with that in the cell response compared with that in the Stage I (initial) lesionStage I (initial) lesion

The junctional epithelium becomes densely The junctional epithelium becomes densely infiltrated with neutrophils, as does the infiltrated with neutrophils, as does the gingival sulcus gingival sulcus

The junctional epithelium may begin to The junctional epithelium may begin to show development of rete pegs or ridgesshow development of rete pegs or ridges

Increase in the amount of collagen Increase in the amount of collagen destructiondestruction

The main fiber groups that are affected The main fiber groups that are affected appear to be the circular and Dentogingival appear to be the circular and Dentogingival fiber assembliesfiber assemblies

PMNs that have left the blood vessels in PMNs that have left the blood vessels in response to chemotactic stimuli from response to chemotactic stimuli from plaque components travel to the plaque components travel to the epithelium, cross the basement lamina, epithelium, cross the basement lamina, and are found in the epithelium and and are found in the epithelium and emerging in the pocket areaemerging in the pocket area

PMNs are attached to bacteria and engulf PMNs are attached to bacteria and engulf them in a process of phagocytosisthem in a process of phagocytosis

PMNs release their lysosomes in PMNs release their lysosomes in association with the ingestion of bacteria association with the ingestion of bacteria

HOST RESPONSEHOST RESPONSE ACUTE INFLAMMATORY RESPONSE PHASE: TISSUES RESPOND ACUTE INFLAMMATORY RESPONSE PHASE: TISSUES RESPOND

TO EARLY SIGNALSTO EARLY SIGNALS

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Stage III GingivitisStage III Gingivitis

In In chronic gingivitischronic gingivitis (Stage III), blood (Stage III), blood vessels become engorged and congested, vessels become engorged and congested, venous return is impaired, and the blood venous return is impaired, and the blood flow becomes sluggishflow becomes sluggish

The result is localized gingival anoxemia, The result is localized gingival anoxemia, which superimposes a somewhat bluish which superimposes a somewhat bluish hue on the reddened gingivahue on the reddened gingiva

Extravasation of red blood cells into the Extravasation of red blood cells into the connective tissue and breakdown of connective tissue and breakdown of hemoglobin into its component pigments hemoglobin into its component pigments can also deepen the color of the can also deepen the color of the chronically inflamed gingiva chronically inflamed gingiva The Stage III lesion can be described as The Stage III lesion can be described as moderately to severely inflamed gingivamoderately to severely inflamed gingivaA key feature that differentiates this lesion A key feature that differentiates this lesion from Stage II lesion is the increase in the from Stage II lesion is the increase in the number of number of plasma cellsplasma cells, which becomes , which becomes the preponderant inflammatory cell typethe preponderant inflammatory cell type

HOST RESPONSEHOST RESPONSE IMMUNE RESPONSE PHASEIMMUNE RESPONSE PHASE

Plasma cells invade the connective tissue Plasma cells invade the connective tissue not only immediately below the junctional not only immediately below the junctional epithelium, but also deep into the epithelium, but also deep into the connective tissue, around blood vessels, connective tissue, around blood vessels, and between bundles of collagen fibers.and between bundles of collagen fibers.The junctional epithelium reveals widened The junctional epithelium reveals widened intercellular spaces filled with granular intercellular spaces filled with granular cellular debris, including lysosomes cellular debris, including lysosomes derived from disrupted neutrophils, derived from disrupted neutrophils, lymphocytes and monocyteslymphocytes and monocytesThe lysosomes contain acid hydrolases The lysosomes contain acid hydrolases that can destroy tissue componentsthat can destroy tissue components

The junctional epithelium develops rete The junctional epithelium develops rete pegs or ridges that protrude into the pegs or ridges that protrude into the connective tissue, and the basal lamina is connective tissue, and the basal lamina is destroyed in some areasdestroyed in some areas

In the connective tissue, collagen fibers In the connective tissue, collagen fibers are destroyed around the infiltrate of intact are destroyed around the infiltrate of intact and disrupted plasma cells, neutrophils, and disrupted plasma cells, neutrophils, lymphocytes, monocytes, and mast cellslymphocytes, monocytes, and mast cells

HOST RESPONSEHOST RESPONSE REGULATION & RESOLUTION PHASE: REGULATION & RESOLUTION PHASE:

DETERMINANTSDETERMINANTS

Interleukins:Interleukins:IL-1 IL-1 ●● Stimulates other cells to Stimulates other cells to

proliferate, activate, and chemotaxproliferate, activate, and chemotax

● ● Stimulates IL-2 secretionStimulates IL-2 secretion

● ● Pyogenic (fever inducing)Pyogenic (fever inducing)

IL-2 IL-2 ● ● Produced by activated T cellsProduced by activated T cells

● ● Stimulates T cells ( helper, Stimulates T cells ( helper, cytotoxic and natural killer cellscytotoxic and natural killer cells

●● Stimulates B cellsStimulates B cells

IL-3 IL-3 ● ● Secreted by activated T cellsSecreted by activated T cells ● ● Stimulates bone marrow stem Stimulates bone marrow stem

cellscellsIL-4 IL-4 ● ● Secreted by activated helper Secreted by activated helper

cells and mast cellscells and mast cells ● ● Stimulates B cellsStimulates B cells ● ● Increases IgG and IgEIncreases IgG and IgEIL-5 IL-5 ●● Secreted by activated helper Secreted by activated helper

cells and mast cellscells and mast cells ● ● Promotes IgA and increases Promotes IgA and increases

synthesis of eosinophilssynthesis of eosinophils ● ● Promotes B-cell proliferationPromotes B-cell proliferation

IL-6 IL-6 ● ● Stimulates production of acute Stimulates production of acute phase reactantsphase reactants

● ● Stimulates B-cellsStimulates B-cells

IL-7 IL-7 ● ● Stimulates pre-B and pre-T cellsStimulates pre-B and pre-T cells

IL-8 IL-8 ● ● Stimulates chemotaxis and Stimulates chemotaxis and adhesion of neutrophilsadhesion of neutrophils

IL-10IL-10● ● Inhibits cytokine release from Inhibits cytokine release from macrophagesmacrophages

● ● Inhibits interferon synthesis by Inhibits interferon synthesis by Th1 cellsTh1 cells

IL-12 IL-12 ●● Activates natural killer cells Activates natural killer cells

●● Induces Th →Th1Induces Th →Th1

●● Increases CTL and DTH cell Increases CTL and DTH cell numbersnumbers