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Oral Pathology - NEETMDS- courses
NEET MDS Lessons
Oral Pathology

Regional Odontodysplasia

  • Key Feature: Widened pre-dentin layer
  • Histology: Large areas of interglobular dentin

Supernumerary Roots

  • Most Common: Mandibular canines and premolars

Congenitally Missing Teeth

Permanent Teeth (Descending Order):

  1. Third molar
  2. Mandibular 2nd premolar
  3. Maxillary lateral incisor
  4. Maxillary 2nd premolar

Deciduous Teeth: Maxillary and mandibular lateral incisors

Species Role
Streptococcus mutans Initiates caries; highly acidogenic/aciduric
Streptococcus sobrinus Similar to S. mutans, less adhesive
Lactobacillus spp. Progression in dentin; acid-loving
Actinomyces naeslundii/viscosus Linked with root surface caries
Veillonella spp. Lactate metabolizers in advanced lesions
Scardovia wiggsiae Emerging cause in early childhood caries
Propionibacterium, Bifidobacterium, Rothia Found in deep dentinal lesions

Gemination

  • Attempted division of a single tooth germ before calcification.

  • Results in two crowns (complete/incomplete) with one root and canal.

  • Tooth count remains normal.

  • Difficult to differentiate from fusion with a supernumerary tooth.

 Twinning

  • Complete division of a single tooth germ.

  • Results in one normal + one supernumerary tooth.

  • Tooth count is more than normal.

Fusion

  • Union of two separate tooth germs.

  • If before calcification → single large tooth.

  • If after calcification → roots fused, crowns may be separate.

  • More common in deciduous teeth.

Concrescence

  • Union by cementum only.

  • Occurs after root formation.

  • Common in maxillary molars.

  • Derived from Reduced Enamel Epithelium (REE):

    • Dentigerous Cyst

    • Eruption Cyst

    • Paradental Cyst

  • Derived from Rests of Serres (remnants of dental lamina):

    • Odontogenic Keratocyst (OKC)

    • Gingival Cyst of Newborn

    • Gingival Cyst of Adult

    • Lateral Periodontal Cyst

    • Glandular Odontogenic Cyst

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

  • Radicular Cysts: Derived from Rests of Malassez.

  • Impacted Canine Associations:

    • Most common odontogenic cyst: Dentigerous cyst.

    • Most common odontogenic tumor: Adenomatoid Odontogenic Tumor (AOT).

  • Eruption Cyst: Considered an extra-alveolar dentigerous cyst (soft tissue counterpart).

Infective osteomyelitis

  • Tuberculous osteomyelitis
  • Syphilitic osteomyelitis
  • Actinomycotic osteomyelitis

Tuberculous osteomyelitis

  • Non healing sinus tract formation
  • Age group affected is around 15 – 40 years.
  • Commonly seen in phalanges and dorsal and lumbar vertebrae.
  • Usually occurs secondary to tuberculosis of lungs.
  • Cases have been reported where mandibular lesions were not associated with pulmonary disease.
  • Another common entrance is through a carious tooth via open pulp.
  • Usually affects long bones and rare in jaws.
  • Results when blood borne bacilli lodge in cancellous bone. Usually in ramus , body of mandible. may mimic parotid swelling or submassetric abscess.

Syphilitic osteomyelitis

  • Difficult to distinguish syphilitic osteomyelitis of the jaws from pyogenic osteomyelitis on clinical & radiographic examination.
  • Main features are progressive course & failure to improve with usual treatment for pyogenic osteomyelitis.
  • Massive sequestration may occur resulting in pathologic fracture.
  • If unchecked, eventually causes perforation of the cortex.

Actinomycotic Osteomyelitis

  • The organisms thrive in the oral cavity, especially tissues adjacent to mandible.
  • May enter the bone through a fresh wound, carious tooth or a periodontal pocket at the gingival margin of erupting tooth.
  • Soft or firm tissue masses on skin, which have purplish, dark red, oily areas with occasional zones of fluctuation.
  • Spontaneous drainage of serous fluid containing granular material.
  • Regional lymph nodes occasionally enlarged.
  • Mimics parotitis / parotid tumors

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