• Dentigerous Cyst (Follicular Cyst):

  • Most common Developmental Odontogenic Cyst.

  • Always associated with the crown of an unerupted/impacted tooth.

  • Derived from Reduced Enamel Epithelium (REE).

  • Differential diagnosis: Eruption cyst, Paradental cyst (also from REE).

• Nasopalatine Duct Cyst (Incisive Canal Cyst/Median Anterior Maxillary Cyst - MAMC):

  • Most common Developmental Non-odontogenic Cyst.

  • Located in the midline of the anterior maxilla.

• Radicular Cyst (Periapical Cyst):

  • Most common Odontogenic Cyst overall.

  • Always associated with a non-vital tooth.

  • Inflammatory origin.

• Odontogenic Keratocyst (OKC) / Keratocystic Odontogenic Tumor (KCOT):

  • Primordial Cyst: An OKC found in place of a missing tooth.

  • Protein Content: Less than 4 gm/dL.

  • Aggressive Behavior: High mitotic activity, high PCNA index, and Ki67 activity.

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

• Mucocele:

  • Common term for:

    • Mucous Extravasation Phenomenon (Pseudocyst): No epithelial lining.

    • Mucous Retention Cyst (True Cyst): Has an epithelial lining.

 Benign Migratory Glossitis

• Also called Erythema migrans, wandering rash, or geographic tongue.

• Associated with fissured tongue.

Fissured Tongue

• Seen in:

  • Melkersson-Rosenthal syndrome

  • Down syndrome

  • Benign migratory glossitis

Melkersson-Rosenthal Syndrome

• Triad:

  • Bell’s palsy

  • Cheilitis granulomatosa (lip/facial swelling)

  • Fissured tongue

Ankyloglossia

• Tongue-tie may cause speech defects.

• Affects articulation of: l, r, t, d, n, th, sh, z

• Actinomycosis (Sulfur Granules):

  • Yellow sulfur granules: Are actually bacterial colonies.

  • Histopathology: Colonies appear "cotton wool" shaped. (Note: "Cotton wool appearance" is seen radiographically in Paget's disease).

• Tuberculosis (TB):

  • Diagnosis (Gold Standard): Presence of acid-fast bacilli in sputum.

  • Staining Method: Ziehl-Neelsen staining method is used to identify acid-fast bacilli.

  • Scrofula: TB of cervical lymph nodes.

  • Lupus Vulgaris: TB of skin.

• Tongue & Gingival Appearance in Systemic Conditions:

  • Strawberry tongue and Raspberry tongue: Seen in stomatitis of Scarlet Fever.

  • Strawberry Gingivitis: Seen in Wegener's Granulomatosis.

Benign Lymphoepithelial Lesion / Mikulicz Syndrome

• Chronic enlargement of lacrimal and salivary glands

• Associated with Sjogren’s syndrome

Sialosis / Sialadenosis

• Non-inflammatory, non-neoplastic enlargement of salivary glands

Sialadenitis

• Inflammatory disease of salivary glands

 Sialadenoma Papilliferum

• Papillomas of salivary gland excretory ducts

Atresia

• Congenital absence or occlusion of major salivary gland ducts

Sialorrhea

• Increased salivation

• Seen in conditions like Parkinson’s disease

 Sialolithiasis

• Salivary duct stones in glands or ducts

• Common in submandibular gland

 Sialodochitis

• Inflammation of salivary gland ducts

Exception Alert: Serum alkaline phosphatase is raised in all of the following except: ➡️ Osteogenesis Imperfecta

Chronic Osteomyelitis

• As soon as pus drains intra or extraorally, condition ceases to spread and chronic phase commences.
• Infection is localized but persistent as bacteria are able to grow in dead bone inaccessible to body’s defenses.

Clinical features

• Primary – insidious in onset , slight pain , gradual increase in jaw size.
• Secondary - Pain is deep pain and intermittent, temperature fluctuations , pyrexia , cellulitis eventually leading to abscess
• New bone formation leads to thickening causing facial asymmetry.
• Thickened or “wooden” character of bone in cr sec osteomyelitis.
• Eventually cures itself as the last sequestra is discharged.

Radiographic Features

• Trabeculae in the involved area become thin or appear fuzzy & then lose their continuity.
• After some time “moth eaten” appearance is seen
• Sequestra appear denser on radiographs.
• Where the subperiosteal new bone formation , the new bone is superimposed upon that of jaw, “fingerprint” or “orange peel” appearance is seen
• Cloacae seen as dark shadows passing through opacity.

Histologic features

• Areas of acute and subacute inflammation in the cancellous spaces of the necrotic bone.
• Foci of acute inflammation
• Active osteoclastic resorption of bone noted in peripheral portions

Chronic Subperiosteal Osteomyelitis

• Cortical plate deprived of its blood supply undergoes necrosis, underlying medullary bone  is slightly affected.
• Multiple small sequestra form, eventually discharged through sinuses with pus.
• Following extrusion of sequestra, healing occurs.
• Spontaneous drainage poor in submassetric area.
• Much of  body of mandible is lost due to poor central blood supply of the region.

D/D

• Paget’s disease – particularly wen periosteal bone is involved
• Fibrous dysplasia
• Osteosarcoma

Chronic sclerosing osteomyelitis

– focal

- diffuse

Focal Sclerosing Osteomyelitis

Clinical features

• Most commonly in children and young adults, rarely in older individuals.
• Tooth most commonly involved is the mandibular third molar presenting with a large carious lesion.
• No signs or symptoms other than mild pain associated with infected pulp.

Radiographic features

• Entire root outline always visible with intact lamina dura.
• Periodontal ligament space widened.
• Border smooth & distinct appearing to blend into surrounding bone

D/D for focal sclerosing osteomyelitis

• Local bone sclerosis
• Sclerosing cementoma
• Gigantiform cementoma

Treatment & prognosis

• Affected tooth may be treated endodontically or extracted.
• Sclerotic bone  not attached to tooth and remains behind after tooth is removed.
• This dense area may not get remodeled.
• Recognizable on bone years later and is referred as bone scar.

Diffuse Sclerosing Osteomyelitis

• May occur at any age, most common in older persons, esp in edentulous mandibles
• vague pain, unpleasant taste.
• Many times spontaneous formation of fistula seen opening onto mucosal surface to establish drainage
• Slowly progressive, not particularly dangerous since it is non destructive & seldom produces complications

Radiographic features

• Diffuse patchy, sclerosis of bone – “cotton wool” appearance
• Radiopacity may be extensive and bilateral.
• Due to diffuse nature, border between sclerosis & normal bone is often indistinct

D/D for DIFFUSE sclerosing osteomyelitis

FLORID OSSEOUS DYSPLASIA

SCLEROTIC CEMENTAL MASSES

TRUE CHR DIFFUSE SCLEROSING OSTEOMYELITIS

FIBROUS DYSPLASIA

Treatment & Prognosis

• Resolution of adjacent foci of chronic infection often leads to improvement.
• Usually too extensive to be removed surgically,
• Acute episodes treated with antibiotics.