JAMISON SPENCER
Well , IT AIN ’ T THE DISC GOING OUT OF PLACE like virtually all patients think ( and unfortunately many dental professionals think — which is why patients are told , “ hey , if your jaw clicks when you open , just don ’ t open so wide ”).
When a patient opens their mouth and they have a click / pop in one or both TM joints , it is typically a disc that was out of position ( displaced or dislocated ) going back into the correct position (“ reducing ”— which is a medical term for going back into the proper anatomical position — for example “ reducing a fracture ”).
Dr . Westesson and Erickson ’ s videos are , in my opinion , still the very best work that has been produced to show the normal joint and what is going on with the clicking .
Here is the normal joint :
Notice the “ joint space ” between the condyle and the top of the fossa . There is sooooo much room , and the disc sits on the condyle without a problem .
Now here is a clicking joint , or a “ disc displacement with reduction :”
Notice that there is virtually no joint space when the patient has their teeth in occlusion . In other words , the disc couldn ’ t stay on the condyle if it wanted to ! There is no room !!
Now , let ’ s take our patient with a reducing disc displacement and treat them with an oral appliance for their sleep apnea .
The appliance holds the mandible down and forward , right ?
What will this USUALLY do for the condyle / disc relationship ? It will have the effect of “ reducing ” the disc displacement , while the appliance is in place .
So the patient wears the appliance for 6-8 hours per night . Her disc is then in place for 6-8 hours , instead of being out of place like it was before treatment .
Is that better or worse for the joint ?
Better , right ?
But what happens when the patient wakes up ? How will her occlusion feel ? If the disc stays in place , will that effect the patient ’ s bite ? You bet it will ! The patient will have a posterior open bite . IF THE DISC IS IN THE CORRECT POSITION , THE TEETH WILL NOT OC- CLUDE LIKE THEY USED TO .
What do we do ? Tune in for Part Two .
DR . JAMISON SPENCER DMD , MS
JAMISON R . SPENCER IS THE DIRECTOR OF THE CENTER FOR SLEEP APNEA AND TMJ IN BOISE IDAHO . HE IS ADJUNCT FACULTY AT UOP AND UNC .
FOR QUESTIONS OR COM- MENTS PLEASE REACH HIM AT JAMISON @ JAMISONSPENCER . COM