radiographs of the TMJ

Question 1

DJD / osteoarthritis

Answer 1

1) occurs when the load on the TMJ exceeds the body’s ability to withstand it
2) will show as flattening and discontinuity of cortex
3) when load decreases, the cortex will start to close again, but will not become round again

Question 2

shape of TMj

Answer 2

1) healthy
- round
- intact cortex
2) DJD active
- shape flattened
- cortex interrupted
3) inactive DJD
- shape flattened
- cortex intact / sclerotic

Question 3

DJD occlusal changes

Answer 3

1) posteriors may wear on the occlusals to compensate
- the rest of the teeth will remain in contact
2) teeth may not be able to compensate eventually
- anterior open bite develops (less common)

Question 4

with active DJD

Answer 4

1) avoid orthodontics
- why arrange occlusion when it will open up afterwards
2) esthetic work
- if they develop anterior open bite after veeners, they will be dissatisfied

Question 5

with active DJD caution with distalmost teeth

Answer 5

1) between crown prep and delivery
- occlusal clearance may collapse rapidly
- temporary may break repeatedly
2) DO composite may fracture or dislodge repeatedly
3) Implant may fail due to overloading

Question 6

if DO has to be done

Answer 6

1) tell them it may fracture repeatedly
2) not as much of a concern on non-distalmost teeth

Question 7

With Inactive Degenerative Joint
Disease

Answer 7

1) treat it like a
normal/healthy joint
* Except remember that DJD could always re-activate
* If they respond to stressors with DJD, it could happen again
2) let them know there is some risk bite may shift sometime in the future

Question 8

individual slices

Answer 8

1) middle upper
- birds eye view
2) right and left coronal view in corns
3) right and left sagittal view
- 6 adjacent slices each
- show progressively deeper slices
4) Allow detection of much smaller (earlier) cortical interruptions than Pano
- By the time a cortical interruption shows on a pano (moderate size), it’s often past the point of opportunity for
meaningful dental intervention

Question 9

why cant a pano detect small breaks

Answer 9

1) x-ray beam has to pass through lots of healthy cortex
2) cannot be detected if there is more healthy cortex relative to interrupted cortex

Question 10

individual slices avoid obscuring by other structures

Answer 10

1) The superiormost 10% is what gets obscured in a PANO
- because it passes through the socket
2) unfortunately, this is the only area where cortical interruption occurs

Question 11

Non-distorted imaging (while in maximum intercuspation bite) allows

Answer 11

assessment of position of the TMJ condyle
- cannot be visualized on a pano because it takes a round skull and flattens it (distorted)

Question 12

When to Re-Scan Active DJD To
Determine If It Has Become Inactive

Answer 12

1) At least 6-12 months after the prior scan
* Recortication takes 6 months to show radiographically
2) needs to be done before othodontics are done

Question 13

Between scans:

Answer 13

Habit reduction
1) First 1-2 weeks:
* Oral Behaviors Checklist (ask WHY?)
* Hourly reminders
* Determine causes
2) Subsequently
* Address causes
* Periodic timers to check on progress

Question 14

The longer the wait, the less

Answer 14

• Radiation
• Feedback on progress

Question 15

round condyle

Answer 15

1) looks like a thumb with a clear cortical border (thumbnail)
2) should be centered in fossa

Question 16

sclerosis

Answer 16

1) thickening of cortex where there is pressure
2) implies the joint has been stressed and was able to close the interruption

Question 17

mild DJD

Answer 17

1) continuous cortex
2) mild flattening

Question 18

pressure =

Answer 18

force/area

Question 19

moderate DJD inactive

Answer 19

1) moderate flattening
2) may or may not have discontinuous cortex
3) osteophytes visible (look like bird beaks in every slice)
- span the whole area

Question 20

moderate DJD, active

Answer 20

1) subchondral cysts
- areas of erosion
2) interrupted cortex
3) osteophytes do not go away
- so this is a sign it was previously inactive

Question 21

severe DJD

Answer 21

1) severe flattening
2) subchondral cysts
3) osteophyte may be broken off
4) bony ligament
3) irregular surface

Question 22

severe rheumatoid arthritis

Answer 22

1) looks similar to DJD
2) body attacks the joint
3) should already have a systemic diagnosis, so we can tell it is caused by mid-late stage
- ask them if they have OTHER joint pain if they do not know

Question 23

idiopathic condylar resorption

Answer 23

1) flattening of TMJ with no clear overload, joint degeneration, etc
2) no cause can be determined
3) likely to develop anterior open bite