NEET MDS Lessons
Oral Pathology
Osteomyelitis
Osteomyelitis is an extensive inflammation of a bone. It involves the cancellous portion, bone marrow, cortex, and periosteum
Conditions that alter HOST IMMUNITY
Leukemia, Severe anemia, Malnutrition, AIDS, IV- drug abuse, Chronic alcoholism, Febrile illnesses, Malignancy, Autoimmune disease, Diabetes mellitus, Arthritis, Agranulocytosis
Conditions that alter vascularity of bone
Osteoporosis, Paget’s disease, Fibrous dysplasia, Bone malignancy, Radiation, Virulence of the organisms
Certain organisms precipitate thrombi formation by virtue of their destructive lysosomal enzymes.
Organisms proliferate in enriched host medium while protected from host immunity.
Etiology
- Odontogenic infections
- Trauma
- Infections of oro facial region
- Infections derived from hematogenous route
- Compound fractures of the jaws.
PATHOGENESIS
DEV . OF INFECTION --> BACTERIAL INVASION --> PUS FORMATION --> SPREAD OF INFECTION --> INCREASED INTRAMEDULLARY PRESSURE , BLOOD FLOW , OSTEOCLASTIC ACTIVITY --> INFLAMMATORY RESPONSES --> INCREASED PERIOSTEAL PRESSURE --> PROCESS BECOMES CHRONIC GRANULATION TISSUE FORMATION --> LYSIS OF BONE --> SEQUESTRUM FORMATION
Classification
Classification based on clinical picture, radiology, and etiology
Suppurative osteomyelitis
I. Acute suppurative osteomyelitis
II. Chronic suppurative osteomyelitis
– Primary chronic suppurative osteomyelitis
– Secondary chronic suppurative osteomyelitis
III. Infantile osteomyelitis
Nonsuppurative osteomyelitis
I. Chronic sclerosing osteomyelitis
– Focal sclerosing osteomyelitis
– Diffuse sclerosing osteomyelitis
II. Garre's sclerosing osteomyelitis
III. Actinomycotic osteomyelitis
IV. Radiation osteomyelitis and necrosis
Non-epithelial cysts (not true cysts)
Solitary bone cyst
Radiology
The solitary bone cyst appears as a well-defined but non-corticated radiolucency. Typically, it has little effect
on adjacent structures and 'arches' up between the roots of teeth .
The inferior dental canal may not be displaced, but the cortical margins of the canal may be lost where it overlies the lesion. Expansion is rare.
Pathology
The cyst is lined by fibrovascular tissue that often includes haemosiderin and multinucleate giant cells.
Aneurysmal bone cyst
Radiology
The aneurysmal bone cyst typically presents as a fairly well-defined radiolucency. Sometimes it has a multilocular appearance because of the occurrence of internal bony septa and opacification. Marked expansion is a feature.
Pathology
The predominant feature of an aneurysmal bone cyst is the presence of blood-filled spaces of variable size lying in a stroma rich in fibroblasts, multinucleate giant cells and haemosiderin. Deposits of osteoid are also seen
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
Streptococcus mutans Mechanism
- Key Substrate: Sucrose
- Metabolic Pathway: Phosphorylation → Glycolysis → Lactic acid
- Enzymes:
- Invertase: Converts sucrose to glucose + fructose
- Glucosyltransferase (GTF): Forms sticky glucans
- Fructosyltransferase (FTF): Produces fructans
Actinomyces naeslundii
- Fimbriated surface → fuzzy texture
- Type 1 fimbriae: Bind tooth surfaces/collagen
- Type 2 fimbriae: Bind galactose/galactosamine (epithelial/bacterial targets)
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
-
Zone 1 – Normal Dentin:
Healthy tissue; no treatment needed -
Zone 2 – Subtransparent Dentin:
Acid-demineralized, no bacteria, remineralizable; preserve -
Zone 3 – Transparent Dentin:
Softened, no bacterial invasion; remineralizable; preserve -
Zone 4 – Turbid Dentin:
Bacterial invasion; not remineralizable; must be removed -
Zone 5 – Infected Dentin:
Fully decomposed; heavily infected; must be removed
|
Condition |
Key Features |
|
Paget's Disease |
- Denture tightening (arch expansion) |
|
Osteopetrosis |
- Rugger jersey spine |
|
Fibrous Dysplasia |
- Leontiasis ossea |
|
Cemento-Ossifying Fibroma |
- Leontiasis ossea |
|
Hyperparathyroidism |
- Ground glass appearance (Brown tumor) |
|
Cherubism |
- Giant cells + vascular stroma + hemosiderin |
|
Central Giant Cell Granuloma |
- Giant cells + vascular stroma + hemosiderin |
|
Juvenile Ossifying Fibroma |
- More aggressive than COF |
Mnemonics Flashcards
|
Mnemonic |
Meaning |
|
Paget's Patients Prefer Tight Dentures |
Paget's → Denture tightening due to arch expansion |
|
Fibrous Faces Feel Funny |
Fibrous dysplasia → Leontiasis ossea, Chinese script, Ground glass, Hockey stick femur |
|
Giant Cells Have Three Homes |
Seen in: Hyperparathyroidism, Cherubism, CGCG |