TMD

Question 1

What nerve gives innervation to the TMJ?

Answer 1

Auriculotemporal nerve, also masseteric nerve and posterior temporal nerve

Question 2

What is the only part of the TMJ that is innervated?

Answer 2

Bilaminar zone

Question 3

Causes of TMD

Answer 3

Myofascial pain (muscles), joint displacement (anterior with or without reduction), degenerative disease (osteoarthritis, rheumatoid arthritis), chronic recurrent dislocation, ankylosis, hyperplasia, neoplasm (tumour), infection

Question 4

Pathogenesis of TMD

Answer 4

Inflammation of muscles of mastication or TMJ secondary to parafunctional habit, trauma either directly to joint or indirectly (e.g. prolonged opening during treatment), stress, psychogenic

Question 5

Intraoral signs of parafunctional habit

Answer 5

Cheek biting (morsicatio buccarum), linea alba, tongue scalloping, occlusal non carious tooth surface loss

Question 6

What would be the first line of management for TMD?

Answer 6

Education/counselling/conservative advice - soft diet, masticate bilaterally, no wide opening, no chewing gum, don’t incise foods, cut food into small pieces, stop parafunctional habits (nail biting, grinding), support mouth on opening (e.g. before yawning put hand under chin or put head down), massage muscles, hot and cold packs

Question 7

What medications could be used?

Answer 7

NSAIDs, muscle relaxants, tricyclic antidepressants, botox (helps paralyse muscles temporarily which could help break clenching habit, only if everything else failed usually), steroids

Question 8

What physical therapies can be used?

Answer 8

Physiotherapy, massage/heat, acupuncture, relaxation, ultrasound therapy, TENS (transcutaneous electric nerve stimulation), hypnotherapy

Question 9

Signs/symptoms of anterior disc displacement with reduction

Answer 9

Jaw tightness/locking i.e. jaw movement impaired for short period of time until disc reduces, mandible may initially deviate to affected side before returning to midline

Question 10

If left untreated what could anterior disc displacement with reduction eventually progress to?

Answer 10

Osteoarthritis

Question 11

Treatment for anterior disc displacement with reduction

Answer 11

Counselling, limit mouth opening, bite raising appliance, surgery occasionally required, if painless no tx required just reassurance

Question 12

What minor traumatic events could possibly cause trismus?

Answer 12

IDB, prolonged dental tx, infection

Question 13

If trismus from trauma doesn’t resolve after acute phase what treatment can be done?

Answer 13

Physiotherapy, therabite (jaw motion rehabilitation system), jaw screw

Question 14

What happens when there is disharmony between movement of condyle and sliding of disc with it?

Answer 14

disc gets dislocated anteriorly and prevents condyle from moving forward (pt will complain limitation of mouth opening)
- So has to be a balance between pulling of disc forward by lateral pterygoid and the elasticity of fibres of bilaminar zone to recapture the disc back

Question 15

What does articular cartilage consist of?

Answer 15

Chondrocyte

Collagen fibres in proteoglycan matrix in addition to hyaluronic acid

Question 16

Inflammatory disease produces proteases and hyaluronidase. What does this do?

Answer 16

Degrade proteoglycans and hyaluronic acid which minimizes movement of disc within TMJ

Question 17

What radiographs could be taken to investigate TMJ?

Answer 17

OPT (may show subcondylar cyst formation), arthrogram, MRI

Question 18

Indications for TMJ reconstruction

Answer 18

Joint destruction
	a) Trauma
	b) Infection
	c) Tumours
	d) Previous surgery
	e) Radiation
Ankylosis
Developmental deformity