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)

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

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

Bacterial & Fungal Infections

Syphilis - Congenital

Hutchinson's Triad:

1. Mulberry molars & peg-shaped incisors
2. VIII nerve deafness
3. Interstitial keratitis

Higoumenaki Sign: Thickened sternoclavicular joint

Rhinoscleroma

• Also Called: Hebra nose

Sarcoidosis

• Diagnostic Test: Kveim–Siltzbach
• Histology: Schaumann bodies

Candidiasis

• Id Reaction: Hypersensitivity to Candida antigen
• Chairside Diagnosis: Wet smear in 10% KOH

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:

1. Nasopalatine cyst - Oval/heart shape, above centrals
2. Median palatine cyst - Posterior to nasopalatine
3. Central giant cell granuloma - More aggressive, may show septations

For Interradicular Radiolucencies:

1. Globulomaxillary cyst - Classic pear shape
2. Lateral periodontal cyst - More cervical location
3. Radicular cyst - Associated with non-vital tooth

Garre’s Osteomyelitis (Chronic Osteomyelitis with Proliferative Perosteitis)

• Chronic Non Suppurative Sclerosing Osteitis/ Periostitis Ossificans.
• Non suppurative productive disease characterized by a hard swelling.
• Occurs due to low grade infection and irritation
• The infectious agent localizes in or beneath the periosteal covering of the cortex & spreads only slightly into the interior of the bone.
• Occurs primarily in young persons who possess great osteogenic activity of the periosteum.

Clinical Features

• Uncommonly encountered, described in tibia and in the head and neck region, in the mandible.
• Typically involves the posterior mandible & is usually unilateral.
• Patients present with an asymptomatic bony, hard swelling with normal appearing overlying skin and mucosa.
• On occasion slight tenderness may be noted
• pain is most constant feature
• The increase in the mass of bone may be due to mild toxic stimulation of periosteal osteoblasts by attenuated infection.

Radiographic features

• Laminations vary from 1 – 12 in number, radiolucent separations often are present between new bone and original cortex. (“onion skin appearance”)
• Trabeculae parallel to laminations may also be present.

Histologic Features

• Reactive new bone.
• Parallel rows of highly cellular & reactive woven bone in which the individual trabeculae are oriented perpendicular to surface.
• Osteoblasts predominate in this area.

D/D for Garre’s Osteomyelitis

• Ewing's sarcoma
• Caffey’s disease
• Fibrous dysplasia
• Osteosarcoma

Treatment

• Removal of the offending cause.
• Once inflammation resolves, layers of the bone consolidate in 6 – 12 months, as the overlying muscle helps to remodel.
• If no focus of infection evident, biopsy recommended.