NEET MDS Lessons
Periodontology
Desquamative Gingivitis
- Characteristics: Desquamative gingivitis is characterized by intense erythema, desquamation, and ulceration of both free and attached gingiva.
- Associated Diseases:
- Lichen Planus
- Pemphigus
- Pemphigoid
- Linear IgA Disease
- Chronic Ulcerative Stomatitis
- Epidermolysis Bullosa
- Systemic Lupus Erythematosus (SLE)
- Dermatitis Herpetiformis
🔻 Anemia Types
🔸 Microcytic
| Type | Features |
|---|---|
| Thalassemia | Microcytic hypochromic RBCs |
| IDA | ↓ ferritin, ↑ TIBC; ↓ bone marrow iron first |
| Hemochromatosis | ↑ ferritin, ↑ iron, ↑ transferrin sat |
| HUS | Fragmented RBCs |
🔸 Macrocytic
- Pernicious anemia: ↓ intrinsic factor
- MCH ↑, MCHC normal
- Hypokalemia during treatment
- Causes: Dietary folate deficiency, celiac disease
- Thiamine deficiency → Lactic acidosis
🔸 Sideroblastic
- Causes: Hypothyroidism, INH therapy
- Treatment: Pyridoxine
- Genetic variant: Pearson syndrome
ANUG symptoms: Metallic taste, Pasty saliva, Punched – out papilla
Red complex: Porphyromonas, Treponema denticola, Tannerella forsythia
Drug enlargement: Phenytoin = Fibrotic, Cyclosporine = Vascular
Healing times: 2 – 7 (epithelialization), 21 (collagen), 1 week (flap attachment)
Bone graft memory: FDBA = Conductive, DFDBA = Inductive
| Disorder | Marker/Feature |
|---|---|
| Hyperkalemia | Tall P wave on ECG |
| Leukemia | Pseudo-hyperkalemia |
| Hypokalemia | Can occur with B12 therapy |
| Calcium Gluconate | Stabilizes myocardium; doesn't lower K⁺ |
🧂 Sodium Imbalance
- SIADH: Hyponatremia, convulsions
- Osmotic demyelination syndrome → too rapid correction
- Pseudohyponatremia: Seen in hyperlipidemia
⚖️ Acid-Base Disorders
| Type | Diagnostic Feature |
|---|---|
| Metabolic Acidosis | ↓ HCO₃⁻ |
| Metabolic Alkalosis | ↑ HCO₃⁻ |
| Respiratory Acidosis | ↑ CO₂ |
| Respiratory Alkalosis | ↓ CO₂ |
- Normal pH: 7.36 – 7.44
- Metabolic alkalosis seen in mineralocorticoid excess
Junctional Epithelium
The junctional epithelium (JE) is a critical component of the periodontal tissue, playing a vital role in the attachment of the gingiva to the tooth surface. Understanding its structure, function, and development is essential for comprehending periodontal health and disease.
Structure of the Junctional Epithelium
-
Composition:
- The junctional epithelium consists of a collar-like band of stratified squamous non-keratinized epithelium.
- This type of epithelium is designed to provide a barrier while allowing for some flexibility and permeability.
-
Layer Thickness:
- In early life, the junctional epithelium is approximately 3-4 layers thick.
- As a person ages, the number of epithelial layers can increase significantly, reaching 10 to 20 layers in older individuals.
- This increase in thickness may be a response to various factors, including mechanical stress and inflammation.
-
Length:
- The length of the junctional epithelium typically ranges from 0.25 mm to 1.35 mm.
- This length can vary based on individual anatomy and periodontal health.
Development of the Junctional Epithelium
- The junctional epithelium is formed by the confluence of the oral epithelium and the reduced enamel epithelium during the process of tooth eruption.
- This fusion is crucial for establishing the attachment of the gingiva to the tooth surface, creating a seal that helps protect the underlying periodontal tissues from microbial invasion.
Function of the Junctional Epithelium
- Barrier Function: The junctional epithelium serves as a barrier between the oral cavity and the underlying periodontal tissues, helping to prevent the entry of pathogens.
- Attachment: It provides a strong attachment to the tooth surface, which is essential for maintaining periodontal health.
- Regenerative Capacity: The junctional epithelium has a high turnover rate, allowing it to regenerate quickly in response to injury or inflammation.
Clinical Relevance
- Periodontal Disease: Changes in the structure and function of the junctional epithelium can be indicative of periodontal disease. For example, inflammation can lead to increased permeability and loss of attachment.
- Healing and Repair: Understanding the properties of the junctional epithelium is important for developing effective treatments for periodontal disease and for managing healing after periodontal surgery.
- Plaque Biofilm:
- Quorum sensing: bacterial communication
- Co-aggregation: Gram-negative adherence
- Microbial Shift (Health → Disease):
- Facultative → Obligate anaerobes
- Fermenting → Proteolytic
- Cocci → Rods
- Non-motile → Motile
- Immunoglobulins:
- Saliva: IgA
- GCF: IgG
- Interleukins & MMPs:
- IL-1β: Most potent bone-destructive cytokine
- MMP-8 & MMP-1: Collagenases
- MMP-2 & MMP-9: Gelatinases
- Activated by neutrophil proteases (e.g., cathepsin G)
Influence of Host Response on Periodontal Disease
The host response plays a critical role in the progression and management of periodontal disease. Various host factors influence bacterial colonization, invasion, tissue destruction, and healing processes. Understanding these interactions is essential for developing effective treatment strategies.
Aspects of Periodontal Disease and Host Factors
-
Bacterial Colonization:
- Host Factor: Antibody C in crevicular fluid.
- Mechanism:
- Antibody C inhibits the adherence and coaggregation of bacteria in the subgingival environment.
- This action potentially reduces bacterial numbers by promoting lysis (destruction of bacterial cells).
- Implication: A robust antibody response can help control the initial colonization of pathogenic bacteria, thereby influencing the onset of periodontal disease.
-
Bacterial Invasion:
- Host Factor: Antibody C-mediated lysis and neutrophil activity.
- Mechanism:
- Antibody C-mediated lysis reduces bacterial counts in the periodontal tissues.
- Neutrophils, through processes such as chemotaxis (movement towards chemical signals), phagocytosis (engulfing and digesting bacteria), and lysis, further reduce bacterial counts.
- Implication: An effective neutrophil response is crucial for controlling bacterial invasion and preventing the progression of periodontal disease.
-
Tissue Destruction:
- Host Factors: Antibody-mediated hypersensitivity and cell-mediated immune responses.
- Mechanism:
- Activation of tissue factors, such as collagenase, leads to the breakdown of connective tissue and periodontal structures.
- The immune response can inadvertently contribute to tissue destruction, as inflammatory mediators can damage host tissues.
- Implication: While the immune response is essential for fighting infection, it can also lead to collateral damage in periodontal tissues, exacerbating disease progression.
-
Healing and Fibrosis:
- Host Factors: Lymphocytes and macrophage-produced chemotactic factors.
- Mechanism:
- Lymphocytes and macrophages release chemotactic factors that attract fibroblasts to the site of injury.
- Fibroblasts are activated by specific factors, promoting tissue repair and fibrosis (the formation of excess connective tissue).
- Implication: A balanced immune response is necessary for effective healing and regeneration of periodontal tissues following inflammation.