• Bull Neck: Seen in Diphtheria and Ludwig's Angina.

• Bull's Eye Lesion / Target Lesions: Characteristic of Stevens-Johnson Syndrome and Erythema Multiforme.

• Bull's Teeth: Refers to Taurodontism.

• Circus Rubber Man: Clinical appearance associated with Ehlers-Danlos Syndrome (due to hypermobility and skin elasticity).

• Claw Hands: A physical deformity seen in advanced Scleroderma.

• Coup de Sabre: A linear depression or groove resembling a "saber cut" seen in Facial Hemiatrophy (Parry-Romberg Syndrome) and localized Scleroderma (linear scleroderma).

• CREST Syndrome: A limited form of Scleroderma, characterized by:

  • Calcinosis

  • Raynaud's phenomenon

  • Esophageal dysfunction

  • Sclerodactyly

  • Telangiectasias

• Crowe's Sign: Axillary or inguinal freckling seen in Neurofibromatosis Type 1.

• Frog Facies: A characteristic facial appearance seen in Crouzon Syndrome (due to midfacial hypoplasia and exophthalmos).

• Gorlin Sign: The ability to touch the tip of the nose with the tongue, seen in Ehlers-Danlos Syndrome (due to increased joint laxity).

• Hockey Stick Deformity of Femur and Shepherd's Crook Sign: Radiographic findings typically associated with Fibrous Dysplasia.

• Parrot's Beak Nose: A nasal deformity seen in Crouzon Syndrome.

• Red Strawberry Tongue and Pastia's Lines: Clinical signs characteristic of Scarlet Fever.

• Rodent Facies: A facial appearance often associated with Thalassemia.

• Simian Stance: A stooped posture, reminiscent of an ape, seen in Paget's Disease of Bone.

• Snail Track Ulcers: Serpiginous, grayish-white lesions on mucous membranes, characteristic of Syphilis (mucous patches in secondary syphilis).

• Socks Feet and Mitten Hands: Refers to syndactyly (fusion of digits) appearing like a sock or mitten, seen in Apert's Syndrome.

• Parrot Beak Shaped Nails: A nail deformity (onychogryphosis) seen in Congenital Syphilis.

1. Zone 1 – Normal Dentin:
   Healthy tissue; no treatment needed

2. Zone 2 – Subtransparent Dentin:
   Acid-demineralized, no bacteria, remineralizable; preserve

3. Zone 3 – Transparent Dentin:
   Softened, no bacterial invasion; remineralizable; preserve

4. Zone 4 – Turbid Dentin:
   Bacterial invasion; not remineralizable; must be removed

5. Zone 5 – Infected Dentin:
   Fully decomposed; heavily infected; must be removed

Miescher Cheilitis

• Definition: Granulomatous inflammation confined to the lip

Melkersson–Rosenthal Syndrome

Triad:

1. Facial palsy
2. Cheilitis granulomatosa
3. Fissured tongue

Ascher Syndrome

Triad:

1. Double lip
2. Blepharochalasis
3. Nontoxic thyroid enlargement

Double Lip

• Appearance: Cupid's bow

• Pulp Polyp (Chronic Hyperplastic Pulpitis):

  • Source of epithelium: Implantation of desquamated cells from saliva or by implantation from oral mucosa due to continuous rubbing.

  • Most common teeth: Deciduous molars and permanent first molars.

• Periapical Granuloma: Always associated with a non-vital tooth.

• Garre's Osteomyelitis: Another name for Chronic Osteomyelitis with Proliferative Periostitis.

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

• Rapid drop in plaque pH after sugar
• Critical pH for enamel demineralization: ~5.5
• Caries-prone individuals:
  • Lower plaque pH
  • Higher Lactobacillus counts

Research Highlights

• Stephan: Rapid pH drop post-carbohydrates
• Caries-free pH: ~7.1
• Caries-active pH: ~5.5
• Maxillary anterior teeth: Greater drop than mandibular
• Stratfors: Lower pH ↔ higher Lactobacillus; plaque buffers better than saliva