Neuromuscular TMJ Diagnosis

Neuromuscular TMJ Diagnosis



Diagnosing TMJ disorders is confusing and difficult for dentists who aren’t specially trained.  In fact, many times symptoms that are related to the problem are not attributed to TMD.  Frequently, muscle tension will cause related symptoms and will be treated in isolation .

A properly trained neuromuscular dentist will have the correct technology for a complete assessment of the health of the TMJ . They will also be able to analyze the articular and intra articular disc of the TMJ. Finally, they will know how to hit the  “reset” button on your bite in order to find its natural resting position.  The following article will provide details of the diagnosis, the reasons behind each step that is taken, the importance of ruling out other disorders and the tools that are used to properly diagnose TMJ disorder.

Skip to Content

What is a TMJ disorder

Step 1: Ruling out Non TMJ Related Causes

Step 2: Causes of TMJ Disorder Symptoms

Step 3: Assessing TMJ Health, Jaw Movement and Bite

Step 4: Finding the Resting Position of the Jaw

Step 5: Recommending a TMJ Treatment


What is Temporomandibular Joint Disorder?

Temporomandibular Joint Disorder (TMD) is an umbrella term covering pain and dysfunction of the muscles of mastication (the muscles that move the jaw) and the temporomandibular joints (the joint connecting the jaw to the skull which allows you to chew, yawn, talk and eat.)  It often occurs in one side of the jaw. Statistics have shown that it is more likely to occur in females than in males.  

Many people refer to the problem as TMJ which is a misnomer.  TMJ really just refers to the jaw joint. Any disorders involving the joint are considered TMD.  Disorders occur in tens of millions in North America alone and cause a range of symptoms that can either be a simple nuisance or completely debilitating.  Many of these TMD symptoms are treated without testing particularly with TMJ headaches, migraines, tinnitus, sleep apnea and neck and shoulder pain.  Other more commonly associated symptoms such as jaw and facial pain, night grinding (bruxism) and lockjaw tend to lead to a diagnosis.  

It was traditionally believed that TMJ disorder treatment required jaw surgery and the source of the pain was the jaw joint itself.  However, recent research has found that up to 90 percent of cases can be treated with non-surgical methods.   Medical professionals agree that jaw surgery should be treated as a last resort for TMJ disorders.

Here we explore the methods and process for TMD diagnosis.  This should be the starting point for anyone who suspects that they may be dealing with the condition.



The Temporomandibular joint (TMJ) combines a hinge action with sliding motions. The parts of the bones that interact in the joint are covered with cartilage and are separated by a small shock absorbing disk.  The first step is to make sure that there are not problems with the TMJ disc or other known causes for the symptoms.

TMD symptoms can occur for many reasons including:

  • Misalignment of the jaw
  • Articular disk erosion
  • Conditions such as arthritis, osteoporosis, infection, tetanus, etc.
  • The joint is damaged by a blow or other impact causing injury

These conditions are often a result of:

  • Malocclusion or trauma to the teeth or jaw
  • Teeth grinding
  • Poor posture
  • Stress
  • Arthritis and other inflammatory musculoskeletal disorders.


According to Dr. Mark Duncan, DDS, the clinical director of LVI Global and the instructor for the Core VII (TMD) curriculum on neuromuscular dentistry, malocclusion and muscle pain are responsible for up to 85 percent of complaints.  However, arthritis, infection, internal derangement and degeneration of the disc are responsible for 10-15 percent of the cases reported.  This means that the majority of patients find relief through non-surgical treatments.  However, it is vital to rule out non-muscular and non-related causes first.

Conditions that may produce similar TMD symptoms include:

  • Atypical (vascular) neuralgia
  • Hypo- and hyperkinesia (abnormal jaw movements)
  • Lyme disease
  • Myositis (muscle inflammation)
  • Myositis ossificans (calcification in a muscle)
  • Otitis (earache)
  • Parotitis (salivary gland inflammation)
  • Scleroderma (chronic hardening of the skin)
  • Sinusitis
  • Temporal arteritis (inflammation of the temporal artery)
  • Toothache
  • Trigeminal neuralgia
  • Tetanus
  • Trotter’s Syndrome (nasopharyngeal carcinoma)



When accompanied by other conditions, TMD is diagnosed by first identifying the cause of the symptoms using clinical examination, medical history and the diagnostic tools described below.

An initial evaluation will include an in depth conversation that will provide the neuromuscular dentist with better insight into the exact causes and symptoms of TMD.  


TMJ Disorder Diagnosis Questions:

Questions you can expect your neuromuscular dentist to ask include:

  • Is your pain or dysfunction occurring on one or both sides of the jaw?
  • What are the common symptoms that tend to reoccur?
  • If there is pain, is it acute or generalized over a wide area?
  • Have you had past injuries to the jaw?
  • Do you have a history of arthritis or joint inflammation?
  • Is there a possibility of infection or nerve related issues?
  • Do you experience popping, clicking or grinding noises from the jaw


Physical Examination:

During the physical exam, your neuromuscular dentist will follow the steps below to gain a better understanding of the physical state of the TMJ.  In many cases they will listen to and feel your jaw as you open and close your mouth.  They will also observe the range of motion in your jaw and measure its passive mouth opening.  In addition, they may press on areas around your jaw to identify sites of pain or discomfort or palpate for masticatory muscles tenderness.

These initial investigatory steps will provide the neuromuscular dentist with the information needed to proceed with a recommendation for TMJ imaging.



In the final phase of the TMD diagnosis your neuromuscular dentist may recommend using the following diagnostic tools:

  • Diagnostic radiology
  • MRI
  • Ultrasonography
  • Electromyography
  • Kinesiograph



Not just any imaging technology is going to work to diagnose TMD.  Panoramic radiograph (X-ray) is a widely used and relatively simple technique to obtain an image of the TMJ.  Conventional plain radiographs, in the form of various TMJ projections, depict mineralized structures of the TMJ. However, the numerous superimpositions of the adjacent structures can make visualization cumbersome.

Axial corrected tomography was previously the imaging technique of choice for diagnosing erosions and osteophytes in the TMJ.  However, these readings may complicate the interpretation of the radiograph in a clinical set up.

Here are the tools that most neuromuscular dentists rely on to provide detailed and accurate images of the area they suspect is the cause of the problem.


Magnetic resonance imaging (MRI) uses a magnetic field and radiofrequency pulses to produce multiple digital image slices.  It is increasingly inexpensive and the TMJ is imaged in the closed and open positions.

Images can be constructed in multiple angles or planes with this non-invasive imaging.  It also allows for images of the disc, muscles and any abnormalities in the joint.

There are times when an MRI is not recommended especially if a patient has any of the following conditions:

  • Pregnancy
  • Pacemakers
  • Intracranial vascular clips
  • The presence of metal particles in vital structures
  • Severe claustrophobia
  • Obesity
  • Inability to remain motionless for the examination which may take several minutes to complete.


Sensitivity to ultrasonography was found to be directly proportional to the quality of the image and ability to detect issues through jaw movement.

The principle of Ultrasonography is based on the fact that ultrasonic sound waves emitted by a device (transducer), travel through TMJ, and are partly reflected through dissimilar anatomical structures.  The reflected sound waves are then read by the same emitting device and are translated into images.

The TMJ region consists of several diverse structures that reflect sound waves differently.  On the sonogram, the disc is shown as a homogeneous area without distinct detail.  

A dentist trained in treating TMD will analyze the position of the disc in a closed mouth position.  Discs with the intermediate zone located anterior to this position are considered to be displaced which is referred to as an internal derangement.

Next they will examine the disc in the open position.  The position of the disc is considered to be normal if the intermediate zone of the disc is located between the condyle and the articular eminence.  If the disc was displaced in the anterior direction, then it is considered to be an internal derangement.

Advantages of Ultrasonography include the following:

  • A more cost effective option
  • Does not require special facilities and thus, it can be easily used in a dental setting
  • High Resolution Ultrasonography (HR-US) can be performed in “real-time” which means that the articular disc can be viewed during the mouth opening movement. This view could help the investigator to detect its position more clearly than in a static image
  • Can be used in patients with pacemakers and metallic implants and in patients experiencing claustrophobia

Disadvantages of Ultrasonography include:

  • Interpretation of the images highly depends on the operator due to the fact that the images can be blurred and unclear.  Thus, well-trained operators are required to obtain reliable results.
  • Since the imaging of the boney structure is clear, the soft tissue and cartilage in the disc itself is not as clear.  It becomes difficult to obtain satisfactory images, especially when the condyle rotates and translates from the mouth-closed position to the mouth-open position. Hence, it becomes necessary to constantly adjust the position of the transducer for a better visual of the disc.   Furthermore, only the lateral part of the TMJ can be reached, while the medial part remains hidden by the mentioned structures.  As a consequence, medial displacements of the disc are likely to be overlooked.


The use of electromyography in TMD diagnosis is based upon the hypothesis that various pathologic and dysfunctional conditions, such as muscle hyperactivity, muscle fatigue and muscle imbalance can be detected from the EMG recording.  

This is a tool that allows a neuromuscular dentist to monitor the electrical impulses generated by the muscles that are associated with the movement of the jaw and alignment of the bite.  This can help to determine whether the muscles remain stressed at their resting position and the relative stress at different jaw positions.

By analyzing this data, they are able to determine if the cause of the jaw pain is structural or muscular which will allow a proper treatment recommendation.

A commercially available example of an EMG used by neuromuscular dentists is the Myotronics /K7 machine


Dr. Bernard Jankelson first successfully utilized the kinesiograph and published his findings in 1980.  Mandibular kinesiograph is a computerized electronic measuring device that can track mandibular movement in three simultaneous planes as well as precisely measuring opening and closing velocity.  This is helpful in establishing a predictable and accurate bite position in diagnosis and treatment.

This tool is highly effective in diagnosing neuromuscular dysfunction as a cause of TMD.  It is important to have a skilled dentist utilizing this tool in order to obtain quality result.  

Commercially available example: K7/CMS Computerized Mandibular Scanner


STEP 4 – Determine Resting Position of the Jaw

TENS Therapy

In cases where the neuromuscular dentist is able to determine that the alignment of the jaw is causing dysfunction, the next step is to identify the natural resting position of the jaw.  

In order to do this a TENS (transcutaneous electric nerve stimulation) unit may be used to relax the jaw muscles and to allow it to settle into its natural position.  

Commercially available example: J5 Myomonitor TENS Unit


Using precisely controlled bilateral stimulation, the monitor will:

  • Relax muscles and establish a physiologic occlusion
  • Take occlusal registrations
  • Treat TMD dysfunction and associated pain
  • Relieve symptoms associated with muscle spasm
  • Increase local blood circulation
  • Increase mandibular range of motion

If this step helps with the symptoms the patient is experiencing, further treatments may be prescribed in order to more permanently relieve the musculoskeletal pain that is caused with TMD.



“Knowing what we know now, it is irresponsible to start a case with surgical end point in mind without exploring non-surgical options first because non-surgical options have very less healing to go through” says Dr. Duncan.

After a proper diagnosis, the following treatment recommendations should be considered

  • Home remedies such as ice and heat application, a regimen including a TMJ diet, rest for the jaw muscles, massage and jaw exercises
  • Orthodontics and restorative dentistry to permanently fix the bite and to reduce the chance of reoccurrence of TMJD symptoms
  • TENS therapy to continue relaxing facial and jaw muscles and to allow a reduction of muscle tension
  • TMJ orthotics (much like an athlete’s mouthguard) to be worn 24 hours a day until the muscles are retrained and the correct bite is restored
  • A TMJ mouth guard to reduce the effects of night grinding, sleep apnea or sensitive teeth
  • Occlusal (bite) adjustment


To find a Neuromuscular dentist that is trained to diagnose TMJ disorders properly, use the search function to find TMJ Dentists.  All dentists listed have completed the LVI Global Core VII curriculum for neuromuscular dentistry and are properly trained in diagnosing TMD.






Kundu, Hansa et al. “Assessment of TMJ Disorders Using Ultrasonography as a Diagnostic Tool: A Review.” Journal of Clinical and Diagnostic Research : JCDR 7.12 (2013): 3116–3120. PMC. Web. 29 Apr. 2016.

Krishnamoorthy, Bhuvana, NS Mamatha, and Vinod AR Kumar. “TMJ Imaging by CBCT: Current Scenario.” Annals of Maxillofacial Surgery 3.1 (2013): 80–83. PMC. Web. 30 Apr. 2016.

- Enter Your Location -
- or -