TMJ/Pain - Assessment
The following video animation depicts the process of changes in TMJ and therefore changes in the bite.
Muscle tenderness is assessed by “palpating” the muscle along its entire length. We rate the tenderness on a scale of 0-3 and palate several muscles of the head and neck region. In addition, the are 2 sets of muscles that are palpated inside the mouth.
Intracapsular pain is tested with a “load test” by bracing the back of the lower jaw bimanually and applying lifting pressure to seat the joints. Upwards pressure is applied in 3 increasing increments. A positive load test at a corresponding increment will most likely indicate anterior disc displacement. Usually accompanied with muscle pain. Definitive diagnosis is from a TMJ MRI.
Osteoarthritic pain will usually be accompanied by muscle pain. Signs of boney changes are a continuous drifting of bite of time. As the bone of the condyle changes (flattens or collapses) the mandible will shift accordingly. This is usually seen as the lower shifting to the affected side. In addition, an anterior open bite may develop. Detection of boney change requires radiographic analysis via one or a combination of the following: TMJ MRI and or TMJ CT scan (see Radiographs page #3).
Doppler Auscultation is non-invasive screening technique used to assess the position of the disc in the TMJ. This is similar to assessing a fetus’ heartbeat using ultrasound. A thin layer of gel is placed over the doppler head and placed immediately in front of the ear canal and behind the condylar head. A normal disc will give a quiet sound upon opening/closing, and left/right motion of the lower jaw. A scratchy sound through one or both movements would indicate an anteriorly displaced disc. A reciprocal clip or pop during either motion will indicate anterior disc displacement with recapture and re-displacement. Scratchy noise in one or both movements indicates the degree of disc displacement. The head of the condyle will have an entirely different orientation in the glenoid fossa than normal. There is usually an accompanied change in the bite with various degrees of disc displacement. Disc displacement can occur in early childhood. It is imperative to diagnose a displaced disc during childhood because it may have the potential to alter growth of the lower jaw. Sometimes TMJ pain can mimmic a middle ear infection. Doppler auscultation is performed on every new patient in order to classify the disc position. Subsequent Doppler procedures may be done based on changes of symptoms, or changes in the bite. A change in the classification will usually be accompanied with a shift in the bite.
A stable bite requires stable joints!