October 16, 2010

Myofacial Pain with Acute Disk Displacement – Case Study

This is the case of a 53y/o/w/f who was referred to our office with acute “TMJ” pain.  She is a snowbird down from Michigan and was being seen at another local dental office. We were called at 9:00 a.m. and she was seen at our office at 1:00 p.m.  These are the actual notes written up in her chart as we progressed through her diagnosis and treatment.

The notes in the chart are in bold and the comments about the notes are in plain text.  Learn how to write the code for this note by referring to the blog entry “How to Design a Carestream/Kodak PracticeWorks Dental Chart Note: Myofacial Pain note”.

Visit #1
The patient has been informed that the T-scan is a computerized sensor designed to measure and record  the biting contacts and forces over time.  It is used to detect prematuraties in tooth contacts that can cause myofacial pain.  The patient was further informed that TMD is an actual physical problem with the TMJ itself and MAY require an oral surgery consult to see if it can be treated surgically.  A complete computerized equilibration can benefit TMD patients but is not usually a cure.  The treatment for myofacial pain at our office is split up into 2 to 4 appointments spread out over a several month period.  It involves this initial assessment appointment where an initial t-scan is taken along with a joint vibration analysis (JVA) is used to R/O TMD and/or myofacial pain, results below:


Patient’s CC is discomfort in joint(s)/facial muscles. Reviewed health history, Patient’s races is caucasian, Pt. has had previous OS consult (at the Michigan Dental School program but before any treatment could be done the program shut down and did not refer her to another provider), Past History of Splint Therapy (Dr. (Local Dentist) gave her an emergency soft guard).  History of snoring and possibly bruxing (Husband),  Recent history of extensive restorative (Dr. “Michigan”) who is up north in Michigan. Her discomfort began right after having several posterior crowns and amalgams changed to composite fillings because the dentist said they needed to be replaced.


Right: Medial Pterygoid muscle TENDER, Temporalis muscle is normal, Masseter belly TENDER, Sternocleidomastoid muscle normal, Digastric Muscle normal, Splenius Capitis Muscle normal, Trapezius Muscle normal, TMJ no capsulitis or ligamentitis noted.

Left: Click/Pop, Medial Pterygoid muscle TENDER, Temporalis muscle is normal, Masseter belly TENDER, Sternocleidomastoid muscle normal, Digastric Muscle normal, Splenius Capitis Muscle normal, Trapezius muscle TENDER, no TMJ capsulitis or ligamentitis noted.

Maximum mouth opening 23mm, No Mandubular Deviation to Rt./Lt., No Crossbite, Angles Class 1,  Generally good Perio, Soft tissue exam appears healthy, Face appears symmetrical, FMA is high, Class 1 Skeletal,


The patient was informed that I feel they have myofacial pain syndrome complicated with acute disk displacement on the left side TMJ.  The cause(s) are many and can be brought on by iatrogenic dentistry, stress, clenching, bruxing, occlusal trauma or other known and unknown factors.

The acute disk displacement diagnosis came from the JVA which will be noted in more detail below.


She has a full arch soft occlusal guard (Dr. “Local”) on the lower to be worn at night and/or during painful events. The patient is further informed that after stablization with additional NTI therapy it will be determined if complete equilibration with the TekScan can relieve the continued source of her discomfort.  Risks, benefits and alternative discussed.  Next Visit: TekScan 1 compete equilibration.

Joint Vibration Analysis Results:

The patient’s maximum opening was 23.0 mm with no deflection from midline.  (Numerics calculated by averaging 6 vibrations.)

Left Side: The onset of the vibration occurred at an estimated 19.6 mm from C.O. during opening, with the mandible moving at an estimated 22.4 mm/sec.  Analysis shows the average total integral (energy) was 17.6 with a peak amplitude of 1.8, indicating a small amplitude vibration. The peak frequency was  48 Hz and the median frequency was  87 Hz.  The ratio of energy above 300 Hz (1.1) to the energy below 300 Hz (16.6) was 0.06.  Dx: Acute disk displacement.

Achieving this diagnosis was done by physically palpating the patient’s joints, and following the Radke-Varga Algorithm provided with the JVA by BioTech.  Once you see the algorithm below it will make a lot more sense.

Right Side: No vibration was found near 16.8 mm from C.O.

The really long vibrations in the window “JVA Sweep” above is the sound of the teeth clicking together and the sound just before that is the actual joint vibration.  You have to manually ID these and mark each vibration to analyze with a box. We placed 6 boxes around vibrations in the same place in the cycle of opening and closing the mouth to get an average reading. Follow the below algorithm using the above numbers under the average left joint analysis to come to the conclusion of acute DD (or disk displacement) remembering her “Max Opening” is only 23 mm.  Also notice that under the “Frequency Spectra” the right side is very quiet, but the left shows a lot of noise below 300 Hz which indicates only a soft tissue component.

X-ray Evaluation:  The patient’s FMX is being seen from her fixed restorative in Michigan.

Preliminary TekScan:

C.O. bite taken, Right/left lateral and protrusive also taken. Occlusion Time A-B increment 0.1292 seconds (0.6 – 96.5%) Left  58% vs. Right 42% @ 96.5% max force.  Sensor sensitivity set at High 1.

This part of the note is a little technical and tells me that she is closing her mouth a little slower than normal and hits more on the left than the right. Remember she only opens her mouth 23 mm so she doesn’t have far to close.  The “Occlusion Time A-B” means that the measurement of time from when the teeth close rapidly together from 0.6% force to 96.5% force is only 0.1292 seconds long.  These factors would never be discovered without a t-scan. And why would you care about this figure? It is a reliable indicator of how fatigued the muscles of mastication are and how much force the patient can generate during mastication. The typical practitioner would put articulating paper between the teeth and see the final results of the teeth being forced together, which may look pretty good. The sensor sensitivity is the second from the highest c/o her acute pain and impaired closing force.

The very first places the patient touchs in maximum intercuspation is on the right side, then it shifts quickly to the left posterior.  Upon both left and right excursions shows both right and left non-working and working side interferences especially on the right side.  Protrusive interferences on the right posterior.

Immediate treatment to help her acute symptoms will be NTI therapy (SEE NTI NOTE) to verify the occlusal trauma component of her discomfort.
NV: T-scan re-eval and possible complete equilibration.

The next two screenshots are of the same maximum intercuspation recording.  The way these recordings are done is the patient is in a sitting position, the sensor is lined up in her mouth and she is instructed to bite down as fast as she can.  We usually practice a few times to condition the sensor (form it to the bite) and to get the patient use to having it in their mouth. I push the “record” button of the sensor handle right before I tell her to close fast.  She holds the bite tight until I say “OK” (about a second later) and then she opens her mouth at which time I press the “Record” button again to stop the recording.  Notice all the static on the first half of the recording.  This is simply artifact from having the record button on while waiting for the patient to bite.

In this first screenshot of the maximum intercuspation recording the lower “Graph” has a slide bar that moves the recording forward and back.  At 25.4% force (the first places the sensor is getting a solid read as the teeth are being closed together tight and fast as possible), the patient touches 80.2% on the right side.

Later in the same fast bite at 96.5% force (close to maximum force) the patient is now biting 58.0% on the left side.  This bite shifts from right to left in the time it takes for the patient to slam their teeth closed.  This takes a lot of muscle memory and it is this that cause lactic acid build-up in the muscles of mastication and therefor myofacial pain.

Although the bar graphs are good illustrators of the bite at any one time in the recording, the “Relative force vs Time” graph is not only the navigator to the recording, but also the quantitive part of the recording.  This is where you calculate the closing and opening speeds (muscle fatigue), right and left side forces, and interferences.  The grey line is the total force (right side + left side), the red line is the right side and the green line is the left.

In left lateral excursion after 75% of the way to canine rise a non-working and a slight group working side interference shows up.  More muscle memory load to fatigue the muscles into lactic acid build-up.

In right lateral excursion you can see the heavy working side interference in the posterior and the non-working side interference on the left posterior.

Protrusive at 80% shows slight interferences bilaterally.

This is the accompanying NTI note in the patient’s chart:


Nociceptive Trigeminal Inhibitor manufactured with acrylic over the maxillary central incisors. Trimmed and polished.  Pt counselled on how to and when to wear.  OHI (wash appliance with soap and water and/or toothpaste and keep in its box when not in use).

Wear the appliance when sleeping and daily during the most stressful times.  Never wear while eating. Discontinue all chewing gum. This is NOT an orthodontic device and should not be worn 24/7.  It REQUIRES the teeth come together each day for at least 8 hours to keep the teeth in proper position. Neuromuscular parafuntional habits may not resolve immediately and can be aggressive in maintaining itself.  If it becomes uncomfortable, too tight or loose, or irritate in any way, the patient has been instructed to contact the office immediately for a follow-up visit.  Risks, benefits and alternatives discussed.

Dogs love to eat NTI. If lost, the patient understands a new one can be made for another full fee.

NV. PRN and re-eval

The patient was called on the phone the next day and she said it was a “miracle”.  Her pain has actually stopped and her mouth now opens wider.  Her joint no longer clicks on the left side.  She is coming in in 2 days for complete equilibration because she will be going back up north for 3 more months before moving back down for the rest of the winter.  The following note was entered into the chart under the simple heading of “Telephone”.

Called patient and she said her jaws were feeling much better. It was a “Miracle”!  NV tekScan 1

Visit #2 (72 hrs after initial visit)

The patient is seated in the operatory and the assistant has their preliminary t-scans up on the computer over the patient’s head so both myself and the patient can see the scans. The patient has been using the NTI to sleep and in between meals and feels great!  She can open her mouth 39 mm without clicking and popping discomfort.

This visit is called tekScan 1.  We generally treatment plan for 3 tekScan appointments for a complete equilibration.  The first appointment is scheduled for 2 hours long and this is where I do the majority of the work (T-scan 2 is usually two weeks later and T-scan 3 is two weeks after that.  They are for any relapse in occlusion, if there is any).  T-scan 1 appointment I first do what I call “lining up the dots” in maximum intercuspation. During this first phase I take out non-functional cusp and incline contacts leaving only point contacts on the functional cusp.  This is directed to the areas where the heaviest forces are concentrated.  This generally begins to balance the bite out for both the right and left sides.  The real beauty of the T-scan is that when most dentist look at all large, heavy articulating ribbon dots as targets, T-scan dentist look at those dots as soft landings. Knowing that large spots can be good and the tiny little spot can be a chisel is very important to understand the whole concept of a complete equilibration.  Placing articulating ribbon in the mouth and asking the patient were they think they are touching first is really primitive if you think about it.  Read more about this in Determining a Relationship Between Applied Occlusal Load and Articulating.

Next the non-working and working side interferences on both the right and left lateral excursions are equilibrated.  For many patients this is a difficult process, and this is where most of their pain originates.  This is good reason to deprogram with a NTI before having a complete equilibration.  Sometimes the sensor can have a hard time picking up these interferences because it is not exactly a normal chewing motion having a sensor in your mouth.  Then once these have been equilibrated out, the protrusive is adjusted out.  I am continually surprised how many people actually have significant protrusive interferences.  I just thought it was something my instructors in dental school through in for the “heck of it”.  To understand protrusive more, after the t-scan recording is done, I look in the mouth and watch the teeth slide forward.  This gives me the good idea of which surfaces touch when sliding the teeth forward.

Below are the final right and left lateral excursions after complete equilibration.

This is the final graph of the maximum intercuspation bite.  Notice the well formed total force curve with rapid closing and opening and that the right and left sides are equal in the middle.

Telephone contacted her two days later and she was feeling much better.  She said her bite never felt better!

Sad to say that I have heard from recent dental students that in school for their occlusion class it felt like “They had just built a campfire and dances around it with a bone in their nose”.  There really is no reason other than money that dental students today do not learn how to treat malocclusions with the state-of-the-art equipment.

Footnote: We use the TekScan II software and the current software is the TekScan III.