NEET MDS Lessons
Oral Pathology
Shape Recognition (Classic Boards Question)
- Heart/Oval Shape → Nasopalatine cyst
- Inverted Pear/Teardrop → Globulomaxillary cyst
- No Radiographic Feature → Nasolabial cyst
Location-Based Diagnosis
- Midline Maxilla (anterior) → Nasopalatine cyst
- Between maxillary lateral incisor & canine → Globulomaxillary cyst
- Midline Mandible → Median mandibular cyst
- Nasolabial fold → Nasolabial cyst
Clinical Correlations
- Spacing between centrals → Nasopalatine cyst
- Root divergence → Globulomaxillary cyst
- Nasal obstruction → Nasolabial cyst
- Usually asymptomatic → Median mandibular cyst
DIFFERENTIAL DIAGNOSIS PEARLS
For Midline Radiolucencies:
- Nasopalatine cyst - Oval/heart shape, above centrals
- Median palatine cyst - Posterior to nasopalatine
- Central giant cell granuloma - More aggressive, may show septations
For Interradicular Radiolucencies:
- Globulomaxillary cyst - Classic pear shape
- Lateral periodontal cyst - More cervical location
- Radicular cyst - Associated with non-vital tooth
Leukoedema
- Diagnostic Feature: Lesions do not rub off; disappear when cheek is stretched
Heck's Disease (Focal Epithelial Hyperplasia)
- Appearance: Cobblestone mucosa
- Also Seen In: Pyostomatitis vegetans, Keratosis follicularis
Infectious Mononucleosis
- Nickname: Kissing disease
- Etiology: Epstein–Barr Virus (EBV)
- SLE → IgG, IgM, IgA deposits at BMZ + superficial lamina propria
- Lichen Planus (Erosive/Atrophic) → Autoimmune T-cell; BMZ involvement
- Cicatricial Pemphigoid → Subepidermal blistering from anti-BMZ antibodies
| Syndrome | Confirmatory Sign |
|---|---|
| Trigeminal Neuralgia | Relief with carbamazepine |
| Eagle’s Syndrome | Relief after styloidectomy |
| Frey’s Syndrome | Positive Minor’s starch-iodine test (sweat mapping) |
| Ramsay Hunt Syndrome | Vesicular eruptions in ear/oral mucosa + facial palsy |
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Epithelial Plaques (localized thickenings): Found in:
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Lateral Periodontal Cyst
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Botryoid Odontogenic Cyst
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Gingival Cyst of Adults
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Glandular Odontogenic Cyst
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Pulp Polyp (Chronic Hyperplastic Pulpitis):
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Source of epithelium: Implantation of desquamated cells from saliva or by implantation from oral mucosa due to continuous rubbing.
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Most common teeth: Deciduous molars and permanent first molars.
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Periapical Granuloma: Always associated with a non-vital tooth.
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Garre's Osteomyelitis: Another name for Chronic Osteomyelitis with Proliferative Periostitis.
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.