Gingivitis is defined as an inflammation which is confined to the tissues of the marginal gingiva . It is an observable alteration in tissues associated with changes in vascular permeability and dilation often accompanied with the infiltration of leukocytes into the affected tissues .

The sequence of events cumulating in the clinically apparent gingivitis is categorized into

• STAGE 1: Initial lesion
• STAGE 2 : Early lesion
• STAGE 3 : Established lesion
• STAGE 4 : Advanced lesion

STAGE 1 : THE INITIAL LESION ( 2- 4days ):

1. VASCULAR CHANGES : Classic vasculitis sub adjacent to junctional epithelium, dilated capillaries , increased blood flow
2. MICROSCOPIC CHANGES : Presence of leukocytes, loss of perivascular collagen and presence of serum proteins changes in the coronal most position of junctional epithelium .
3. CLINICAL CHANGES : Exudation of fluids from the gingival sulcus , sub clinical gingivitis .

STAGE 2 : EARLY LESION (4-7 DAYS ):

1. VASCULAR CHANGES : Vascular proliferation
2. MICROSCOPIC CHANGES : Rete pegs formation in junctional epithelium , presence of lymphocytes , loss of collagen is increased , fibroblasts show cytoplasmic alterations .
3. CLINICAL CHANGES : Bleeding on probing, erythematous gingiva.

STAGE 3 : ESTABLISHES LESION ( 14-21 DAYS ) :

1. VASCULAR CHANGES : Same as early lesion with blood stasis.
2. MICROSCOPIC CHANGES: Proliferation , apical migration and lateral extension of junctional epithelium, atrophic areas , plasma cells are predominant , further loss of collagen, increased enzyme levels of acid and alkaline phosphatase.
3. CLINICAL CHANGES : Changes are seen in color, surface texture and consistency , bluish hue around the reddened gingiva , gingiva appears to be moderately to severely inflamed .

STAGE 4 : THE ADVANCED LESION :

1. VASCULAR CHANGES: Same as early and established lesions. characterized by the invasion of the lesion to the underlying alveolar bone .
2. MICROSCOPIC CHANGES: Persistence of features seen in established lesion, extension of inflammation into deeper structures including alveolar bone and periodontal ligament , presence of all types of inflammatory cells , conversion of bone marrow into fibrous tissues.
3. CLINICAL CHANGES :Formation of periodontal pocket and its associated changes.

REFERENCES: ESSENTIALS OF PERIODONTOLGY SHANTIPRIYA REDDY 5TH EDITION