When it comes to the management of the TMD patient, we need to take a multifactorial approach. First and foremost, there are roles to be played by the patient and the dentist. But we cannot overlook or underestimate the importance of our wider team – the physiotherapist, the chiropractor, the mental health therapist. In atypical cases, our patients may also need diagnosis and intervention by oro-facial pain specialists, ENT, neurologists etc.
Here, we speak to Dr. Brett Weiss, a physiotherapist in Toronto who specialises in TMD, to understand his role and perspective in the management of these patients.
What are the basic exam steps a dentist can take when assessing the TMJ?
Range of Motion:
1. Measure Vertical Opening:
Normal opening range of motion is 40mm-55mm measured from mandibular to maxillary central incisors. Ask them to “open comfortably” at first then measure this number. Then ask them to open as wide as they can and take your second measurement. Note any large discrepancy between the two. Be very mindful to look to see if they lower the mouth correctly or kick the head back into cranial extension to compensate (Their nose will go up if they use their suboccipital muscles too much when opening the mouth).
2. Measure lateral excursion
Normal Lateral Excursion is 8-12mm. First, measure any malalignment of the midpoint between the central incisors when in maximal intercuspation. Note this as left or right deviation (i.e. patient is 4mm deviated left at max intercuspation). Using the midpoint between the maxillary central incisors and the mandibular central incisors, ask the patient to move the jaw to the left. Don’t let them open too wide to do this, just a little space between the teeth. Measure the change in movement. Then reset and measure right. Subtract or add from these numbers whatever midline malalignment you measured when they are resting with teeth together.
What We Expect As Normal
One thing we look for and expect in healthy populations is a 1:4 ratio of lateral excursive movements to opening (i.e. 10mm of lateral movement in someone who opens vertically to 40mm).
What are the meanings of the sounds we hear?
The Auscultation may lead you to suggest imaging or help you with fabricating your occlusal TMJ splints
1) Using a standard stethoscope, place over the TMJ in question and have the patient open and close the mouth listening for signs of intra articular dysfunction such as crepitus, clicking or a thud or clunk sound.
Crepitus: may indicate joint degradation or compression causing a crackling sound that is heard during opening and lateral movements of the jaw and usually distinguishable from a clicking sound which more subtle and heard for shorter duration.
Clunk or Thud Sound: This loud shifting clunk sound is easily heard without auscultating often. This is a subluxation of the mandibular condyle with or without the disc over the articular eminence. These patients respond very quickly to Physio exercises and manual therapy to improve joint mobility on the contralateral TMJ thereby require less hypermobility on the subsiding side.
2) Then assess lateral excursive movements to the left and right.
3) Then repeat these steps with the patient holding standard 1-1.5mm tongue depressors on both mandibular molar arches. If the joint sounds diminish or completely correct then you have more confidence a standard flat plane TMJ orthotic might be helpful for this patient.
What should the TMD patient’s home routine look like?
Home routines should always begin with re-education of correct tongue up posturing. This is a large focus in TMJ physiotherapy and we spend the first few sessions perfecting this. When headache patients or those with hypermobility gain this ability to control the tongue, the reduction in symptoms are often dramatic and rapid to change for the better.
Specific modality recommendations and exercises beyond this are not always best for each individual so it is best to refer patients that you perceive to have TMD to a TMD focused dentist with extra training in orofacial pain or a TMJ-focused physiotherapist.
About the Author: Dr. Brett Weiss, PT, DPT, CEAS, is an experienced physiotherapist with advanced training in manual therapy and devoted much of his practice to evaluation and treatment of cervical spine and temporomandibular disorders, cervicogenic headaches and orofacial pain.