TMJ Disorders (Prof Ayoub) Flashcards
What is the aetiology of TMJD
macrotrauma
microtrauma
occlusal factors
anatomical factors
What is macrotrauma
one sudden incident
What is microtrauma
chronic joint overloading, secondary to stress related repetitive clenching or bruxism
What are occlusal factors
o Deep bite
o Occlusal disharmony e.g high filling
o Lack of teeth
What are examples of anatomical factors
class 2 jaw relation (excessive trauma)
What are symptoms of TMD
Pain may be
o Muscular
o Capsular
o Intracapsular ‘disc’
Reduced mobility
TMJ clicking/locking
What are the 3 parts of the articular disc
anterior part (attached to LP)
posterior part
bilaminar zone
What is teh bilaminar zone formed of
collagen fibres, part of which are attached to the posterior part of the condyle and the other parts to the posterior part of the eminence and the elastic fibres are what bring the disc back again
What does repeated pulling of the disc result in
loss of recoil elasticity of the collagen fibres of the bilaminar zone
What is derangement of the joint
The lateral pterygoid will move the disc forward but the disc may be unable to go back, this is known as derangement of the joint
What type of joint is TMJ
fibrocartilage
What movement is the upper compartment involved in
translation
What movement is the lower compartment involved in
rotation
What help resist the load on the TMJ
Cartilage, synovial fluid, joint shape, muscles and ligaments
What deos the articular cartilage consist of
Chondrocyts
Collagen fibres in proteoglycan matrix
What does inflammatory disease do
produces proteases which degrade proteoglycans
What is the first phaes of clicking
clicking happens in 2 phases
when the bilaminar zone can bring the disc back, the patient says they feel a click/grinding and this is anteriorly dislocated with reduction
What is the second phase of clicking
When the patient cannot open their mouth and is known as anterior dislocated without reduction where the bilaminar zone gives up and cannot bring back the disc
What are the innervated parts of the TMJ
capsule, synovial tissue and subchondral bone
What can compressive forces do to the TMJ
damage proteoglycans which protect collagen
What can shearing forces do to the TMJ
break up collagen fibrils
What are the degenerative changes
Cartilage degeneration: chondromalacia/collagen fibrillation/subchondral bone exposure
Disc perforation
Multiple adhesions
Adhesive capsulitis
Osteophytes
Flattening of condyle and eminence
Subchondral cysts
What does conservative management consist of
- counselling
- pain management
- joint rest
- muscle relaxation
- physical therapy
- restoration of occlusal ability
What are functions of a bite raising appliance
Eliminates occlusal interferences so acts as a habit breaker (main function)
Prevents condyle from rotating so far posteriorly (in the area of the bilaminar zone where there is maximum inflammation) in the glenoid fossa
Reduces loading on TMJ
