Functional Disorders of the TMJ

Question 1

in the condyle-disc complex, the disc is ___ and ___ bound to the condyle by the ___ ligaments

Answer 1

• laterally and medially

- discal collateral

Question 2

the only physiologic movement that can occur between the condyle and the articular disc is ___

Answer 2

rotation

Question 3

rotational movement of the condyle-disc complex is limited by what?

Answer 3

the length of the discal collateral ligaments, inferior retrodiscal lamina posteriorly, anterior capsular ligament anteriorly, morphology of the disc, degree of interarticular pressure, superior lateral pterygoid muscle, and superior retrodiscal lamina

Question 4

the only physiologic translatory movement occurs between the ___ and the ___

Answer 4

condyle-disc complex and the articular fossa

Question 5

describe the steps of normal opening movement

Answer 5

1. mouth opens and condyle moves forward
2. disc rotates posteriorly on the condyle
3. superior retrodiscal lamina lengthens
4. condyle-disc complex translates out of the fossa

Question 6

during normal opening movement, once the condyle-disc complex translates out of the fossa, ___ maintains the condyle on the thinner intermediate zone of the articular disc and prevents the thicker anterior border from passing posteriorly through the discal space between the ___ and ___

Answer 6

• interarticular pressure provided by the elevator muscles

- condyle and the articular surface of the eminence

Question 7

the ___ is the only structure that can retract the disc posteriorly

Answer 7

superior retrodiscal lamina

Question 8

what happens if the morphology of the disc is altered and the discal ligaments become elongated (internal derangement)? is this movement normal in a healthy joint? what is its degree determined by?

Answer 8

the disc is permitted to slide (translate) across the articular surfaces of the condyle. this type of movement is not present in the healthy joint. it’s degree is determined by changes that have occurred in the morphology of the disc and the degree of elongation of the discal ligaments.

Question 9

what happens when the mouth closes during internal derangement?

Answer 9

when the mouth closes, the interarticular pressure is lower, so the disc can once again be displaced forward by tonicity of the superior lateral pterygoid muscle

Question 10

in the healthy joint, the surfaces of the condyle, disc, and articular fossa are ___, allowing ___ movement

Answer 10

slippery, allowing easy, frictionless movement

Question 11

describe reciprocal clicking

Answer 11

1. during mandibular opening, a sound is heard when the condyle moves across the posterior border of the disc to its normal position on the intermediate zone.
2. during closing, the normal disc position is maintained until the condyle returns to very near the closed joint position.
3. as the closed joint position is approached, the posterior pull of the superior retrodiscal lamina is decreased.
4. the combination of disc morphology and pull of the superior lateral pterygoid muscle allows the disc to slip back into the more anterior displaced position. this final movement of the condyle across the posterior border of the disc creates a second clicking sound (“reciprocal click”)

Question 12

___ describes actual dislocation of the articular surfaces

Answer 12

functional dislocation with reduction

Question 13

T or F:
during functional dislocation with reduction, the patient is unable to maneuver the joint successfully to reduce the disc back to its functional position

Answer 13

false

Question 14

is functional dislocation with reduction painful?

Answer 14

may or may not be painful depending on the severity and duration of the lock and the integrity of the structures in the joint

Question 15

what happens during functional dislocation with reduction of episodes of catching/locking become more frequent and chronic?

Answer 15

ligaments break down and innervation is lost. Pain becomes less associated with ligaments and more related to forces placed on the retrodiscal tissues.

Question 16

during ___, the patient is unable to return the dislocated disc to its normal position on the condyle, and the mouth cannot be opened maximally

Answer 16

functional disc dislocation without reduction

Question 17

during functional disc dislocation without reduction, deviation to the affected side occurs in maximum opening that is limited to ___mm. is the patient able to produce normal lateral ROM to the contralateral side?

Answer 17

• 25-30mm

- pt is unable to produce normal lateral ROM to the contralateral side

Question 18

is pain present during functional disc dislocation without reduction?

Answer 18

not necessarily, unless force is applied, stretching the ligaments

Question 19

where does function occur during functional disc dislocation without reduction if pain is felt due to force applied that stretches the ligaments?

Answer 19

• on the retrodiscal tissues
• if sufficient force is applied to these tissues during function, tissue breakdown may occur leading to a perforation of these tissues
• if moderate force is applied during functional movements, these tissues may develop a callous or pseudo disc

Question 20

___ is any sudden force to the joint that can result in structural alterations

Answer 20

macrotrauma

Question 21

___ is a blow to the chin or lateral portions of the mandible that may lead to dysfunctional changes that are irreversible

Answer 21

direct trauma

Question 22

___ trauma has greater risk to joint structures

Answer 22

open mouth

Question 23

___ trauma has stability from the intercuspal position of the teeth and protects the joint tissues to a greater degree (value of athletic mouth appliances)

Answer 23

closed mouth

Question 24

iatrogenic traumas, as in intubation procedures, third molar extractions, and long dental procedures create risk of ___

Answer 24

elongating the discal ligaments

Question 25

indirect trauma symptoms as in whiplash injuries can be explained as heterotropic symptoms associated with ___

Answer 25

deep pain input from the cervical spine

Question 26

___ is any small force that is repeatedly applied to the joint structures over a long period of time (bruxism and clenching)

Answer 26

microtrauma

Question 27

during microtrauma, if loading exceeds the functional limit of the tissue, ___ can result within the ___

Answer 27

irreversible changes or damage can result within the collagen network

Question 28

___ is softening of the articular surface

Answer 28

chondromalacia (example of microtrauma)

Question 29

the ___ theory involves free radicals associated with hyperalgesia

Answer 29

hypoxia/reperfusion theory (example of microtrauma)

Question 30

mandibular orthopedic instability resulting from occlusal disharmony is an example of ___

Answer 30

microtrauma

Question 31

an example of microtrauma is loss of ___ due to alterations in discal surface lubrication

Answer 31

frictionless movement

Question 32

T or F:
studies report that the incidence of TMD symptoms in a population of orthodontically treated patients is no greater than that in the untreated general population

Answer 32

true

Question 33

T or F:

orthodontic treatment is effective in preventing TMDs

Answer 33

• false
• the incidence of TMD symptoms in the orthodontically treated populations were found to be generally NO lower than that in the untreated population

Question 34

any dental procedure that produces an occlusal condition which is not in harmony with the musculoskeletally stable position of the joint can predispose patients to ___

Answer 34

TMDs

Question 35

T or F:
clinicians who provide dental care that will change the patient’s occlusion should follow the principles of orthopedic stability to minimize risk factors for TMDs

Answer 35

true