Radiographic Considerations in TMD

Question 1

What are the different imaging when can you for TMJ diagnostics?

Answer 1

• Pan
• CBCT
• Multidetector computed tomography (MDCT)
• MRI

Question 2

PAN

Answer 2

• Broad overview of TMJ
• Detect Gross osseous changes (FAN LEEO)
  
  • asymmetries
  • extensive erosion
  • large osteophytes
  • neoplasms
  • fractures
• No info about condyle position or function

Question 3

CBCT

Answer 3

• Low radiation dose
• acquired with mouth closed and teeth in MI
• Detect Osseous changes (DJD FAN)
  
  • Degenerative joint disease
  • Ankylosis
  • Neoplasms
  • Fractures
• Cannot see soft tissue lesions (Discs)

Question 4

MDCT

Answer 4

• provides same info as CBCT but
  
  • Limited view of soft tissues
  • Higher radiation dose

Question 5

MRI

Answer 5

• Soft Tissue Pathology
• Mouth is closed and opened when taken
• contraindication:
  
  • Pacemakers
  • Intracranial vascular clips
  • Metal Particles in vital structures
• Stainless steel crowns and ortho=image artifacts

Question 6

TMJ Developmental Abnormalities:

Answer 6

• Condylar hyperplasia
• Condylar hypoplasia
• Coronoid hyperplasia
• Bifid condyle

Question 7

TMJ Soft Tissue Abnormalities

Answer 7

• Disc displacement (reduction vs non-reduction)
• Deformities and perforation
• Fibrous Adhesion and Effusion

Question 8

TMJ Remodeling and Arthritic Conditioning

Answer 8

• Remodeling
• Degenerative joint diseaes
• Rheumatoid Athritis
• Juvenile idiopathic arthritis
• Septic arthritis

Question 9

TMJ Articular Loose bodies

Answer 9

• Synovial Chondromatosis
• Chondrocalcinosis

Question 10

TMJ Trauma abnormalities

Answer 10

• Effusion
• Condylar dislocation
• Fracture
• Neonatal Fractures
• Ankylosis

Question 11

TMJ Neoplasia Abnormalities

Answer 11

• Benign Neoplasia
  
  • osteochondromas
  • osteomas
  • osteoblastomas
  • chondroblastomas
• Malignant Neoplasia
  
  • Primary:
    
    • Chondrosarcoma
    • Osteosarcoma
    • Synovial Sarcoma
  • Metastatic
    
    • Salivary gland
    • breast
    • kidney
    • lung
    • colon
    • prostate
    • thyroid gland

Question 12

Degenerative Joint Disease

Clinical Features

Image Features

Answer 12

• Noninflammatory
• articulating fibrocartilage is broken down
  
  • due to excessive loading
• Clinical Features
  
  • Asympatomatic
  • Pain
  • Join noise (Crepitus)
  • Limited ROM
• Image Features:
  
  • Erosion
  • Osteophyte
  • reduced joint space
  • subcondral sclerosis
  • subcentral cyst (ely cyst)

Question 13

Rheumatoid Arthritis:

Clinical Features

Image features

Answer 13

• Synovial membrane inflammation
• Clinical features
  
  • swelling, pain, tenderness, stiffness
  • Limited ROM
  • Crepitus
  • Anterior open bite
• Imaging Features: (ER SOS GO BF)
  
  • Generalized osteopenia
  • Erosion (“Sharped pencil”)
  • osteophyte
  • reduced joint space
  • Subcondral cyst
  • subchondral sclerosis
  • Fibrous ankylosis
  • Bony ankylosis
• Osteopenia & Severe erosion of articular eminence=More characteristic of RA

Question 14

Disc Displacement:

Normal vs Anterior Displacement w/reduction vs Anterior Displacement w/or reduction

Answer 14

• Anterior displacement in closed position= most common disc displacement
• Normal:
  
  • Close
    
    • posterior band b/w condyle and mandibular fossa
  • Open
    
    • intermediate band b/w condyle and articular eminence
• Anterior displacement w/reduction
  
  • Close:
    
    • disc is anterior displaced
    • posterior band anterior to condyle
  • Open: (Reduces to normal)
    
    • Disc is in normal position
• Anterior Displacement w/o reduction
  
  • Close:
    
    • disc is anteriorly displace
  • Open:
    
    • disc still anterior to condyle

Question 15

Disc displacement: Reduction vs non reduction

Answer 15

• Reduction
  
  • Anterior displaced disc resumes normal position when mouth opens
  • Audible Click
• Non-reduction
  
  • Disc remains anterior displaced when opened
  • Disc bent or deformed

Question 16

TMJ Fracture

Answer 16

• Condylar neck fractures→ most common
• unilateral
  
  • parasymphyseal or mandibular body fracture on contralateral side
• Condyle head displacement in anterior and medial direction

Question 17

TMJ Ankylosis

Answer 17

• Restricted condyle movement
  
  • due to intraarticular or extraarticular causes
• Intraarticular causes
  
  • fibrous ankylosis
    
    • fibrous connection of joint components
  • Bony ankylosis
    
    • Bone bridge connects joint components

Question 18

Eagle Syndrome

Answer 18

• CN impingement due to:
  
  • elongated soloed process
  • ossified sylohyoid ligament
• Related to recent neck trauma
  
  • tonsilectomy
• Symptoms:
  
  • Vague, nagging to intense pain when:
    
    • speaking
    • chewing
    • swallowing
    • turning head
    • open mouth wide
  • Foreign body sensation in throat when swallowing
    
    • feels like something is in your throat when swallowing
  • Very LITTLE correlation b/w extent of ossification & intensity of symptoms
• Treatment:
  
  • Vague symptoms=conservative
    
    • steroid or lidocaine injection in tonsillar fossa
  • Persistent or intense symptoms
    
    • amputate stylohyoid process (Stylohyoidectomy)