NEET MDS Lessons
Oral Pathology
Epithelial cysts
Developmental odontogenic cysts
Odontogenic keratocyst
Dentigerous cyst (follicular cyst)
Eruption cyst
Lateral periodontal cyst
Gingival cyst of adults
Glandular odontogenic cyst (sialo-odontogenic)
Inflammatory odontogenic cysts
Radicular cyst (apical and lateral)
Residual cyst
Paradental cyst
Non-odontogenic cysts
Nasopalatine cyst
Nasolabial cyst
Non-epithelial cysts (not true cysts)
Solitary bone cyst
Aneurysmal bone cyst
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Actinomycosis (Sulfur Granules):
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Yellow sulfur granules: Are actually bacterial colonies.
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Histopathology: Colonies appear "cotton wool" shaped. (Note: "Cotton wool appearance" is seen radiographically in Paget's disease).
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Tuberculosis (TB):
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Diagnosis (Gold Standard): Presence of acid-fast bacilli in sputum.
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Staining Method: Ziehl-Neelsen staining method is used to identify acid-fast bacilli.
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Scrofula: TB of cervical lymph nodes.
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Lupus Vulgaris: TB of skin.
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Tongue & Gingival Appearance in Systemic Conditions:
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Strawberry tongue and Raspberry tongue: Seen in stomatitis of Scarlet Fever.
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Strawberry Gingivitis: Seen in Wegener's Granulomatosis.
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Paget's Disease
- Chief Complaint: Denture tightening (due to arch expansion)
- Fractures: Chalk-stick fractures
- Facial Feature: Leontiasis ossea (lion-like facies)
- Radiology: Cotton wool appearance
- Histology: Jigsaw puzzle pattern
- Clinical: Bone warm to touch (↑ vascularity)
- Laboratory: ↑ Alkaline phosphatase (>250 Bodansky units)
- Other Signs: Osteoporosis circumscripta, platybasia
- Memory Aid: "Paget's Patients Prefer Tight Dentures"
Osteopetrosis
- Radiographic Sign: Rugger Jersey Spine (classic)
- Fractures: Chalk-stick fractures
Fibrous Dysplasia
- Facial Feature: Leontiasis ossea
- Histology: Chinese script pattern
- Radiology:
- Ground glass appearance
- Rind sign, orange peel appearance
- Bone Deformity: Hockey stick/Shepherd's crook deformity (femur)
- Key Feature: Lesional bone fused with normal bone (vs COF)
- Memory Aid: "Fibrous Faces Feel Funny"
Cemento-Ossifying Fibroma (COF)
- Histology: Chinese script pattern
- Facial Feature: Leontiasis ossea
- Difference: NOT fused with normal bone (vs Fibrous Dysplasia)
Hyperparathyroidism
- Radiology: Ground glass appearance (brown tumor)
- Histology: Numerous giant cells, vascular stroma, hemosiderin deposits
Cherubism & Central Giant Cell Granuloma
- Histology: Same as hyperparathyroidism (giant cells + vascular stroma + hemosiderin)
- Note: Cherubism previously called "Familial fibrous dysplasia"
- Memory Aid: "Giant Cells Have Three Homes" (Hyperparathyroidism, Cherubism, CGCG)
Juvenile Ossifying Fibroma
- Aggressiveness: More aggressive than Cemento-ossifying fibroma
- Types:
- Trabecular type: Common in jaws
- Psammomatoid type: Involves base of skull
Gemination
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Attempted division of a single tooth germ before calcification.
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Results in two crowns (complete/incomplete) with one root and canal.
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Tooth count remains normal.
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Difficult to differentiate from fusion with a supernumerary tooth.
Twinning
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Complete division of a single tooth germ.
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Results in one normal + one supernumerary tooth.
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Tooth count is more than normal.
Fusion
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Union of two separate tooth germs.
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If before calcification → single large tooth.
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If after calcification → roots fused, crowns may be separate.
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More common in deciduous teeth.
Concrescence
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Union by cementum only.
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Occurs after root formation.
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Common in maxillary molars.
- Pioneer bacteria invade dentinal tubules before clinical signs
- Tubules contain pure forms:
- One tubule → cocci
- Adjacent tubule → bacilli or threads
- No mixed forms within a single tubule
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Stevens-Johnson Syndrome (SJS):
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Characterized by ulcers with hemorrhagic crusts.
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Typically has an acute onset following drug exposure (mainly sulfa group drugs).
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Biopsy for Vesiculobullous Pathology: Should be taken from the margin of the vesicle/bulla, including a significant amount of normal-appearing mucosa, to capture the pathological changes and adjacent healthy tissue for comparison.
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Linea Alba: A white, bilateral line on the buccal mucosa associated with pressure, frictional irritation, or sucking trauma from the facial surface of teeth.
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Morsicatio Buccarum: Chronic irritation seen on the buccal mucosa as a result of suction and glassblowers (chewing habits).
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Riga-Fede Disease: Sublingual ulcerations in infants resulting from chronic mucosal trauma from adjacent primary teeth (often natal/neonatal teeth).
Leukoplakia
- Type: Clinical term
- Histology: Hyperkeratosis ± Dysplasia
Verrucous Carcinoma
- Type: Variant of SCC
- Features:
- Intact basement membrane
- Parakeratin plugging
- Broad "elephant-foot" rete ridges
Adenosquamous Carcinoma
- Features: Mixed adenocarcinoma + SCC