How to Discover Occlusal Muscle Disorders

By: Dr. Leonard A. Hess, DDS
Clinical Director, The Dawson Academy
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One of the key components of a complete exam is the palpation of the masticatory muscles.

During this part of the exam, we are looking for signs of muscle tenderness or pain. This pain is an indication of hyperactivity resulting from incoordinated muscle activity caused by a build-up of lactic acid due to the muscle(s) being overworked as they hold the jaw in an avoidance pattern during closure to maximum intercuspation.

To be clear, when we talk about hot muscles we are referring to sore or tender masticatory muscles. Indications of these hot muscles are identified in the discovery phase of the complete exam. Oftentimes, patients will be able to readily point out the muscles that are hot since they are causing discomfort.

Red Flags of Occlusal Muscle Disorder When Talking to Your Patient

  • My jaw is sore whenever I chew
  • I have headaches all the time
  • I wake up in the morning and I feel like my jaw has been working all night long

If you hear anything like this from your patient, it’s a good indication of an occlusal muscle disorder at work.

Key Questions to Ask During an Examination to Uncover Hot Muscles

  • Do you have frequent headaches? If so, where and how often?
  • Do you have a history of clenching or grinding?
  • Do you wake up in the morning with your jaw really tired?
  • Do you have any soreness in your muscles? If so, where and when? What causes or relieves the soreness?

If there are any positive responses to these questions, make sure to closely examine all the muscle groups to determine why these muscles are working so hard.

Keep in mind, that no two patients are alike, so each patient has his own threshold for pain. Most people are not aware they are clenching and grinding (sign = worn teeth). I can’t emphasize enough that it is critical not to skip steps in a complete exam because you will often find things you didn’t expect and signs the patient wasn’t even aware of.

One of the best ways to discover any hot muscles is through palpating them in a systematic way during your complete exam. Frequently as I go through the muscle groups, I discover sore and tender muscles that the patient wasn’t even aware of. This process is what we refer to as a co-discovery examination because the patient didn’t tell us about the soreness, but we found it as a result of the complete examination.

So make sure to follow your protocols and palpate all the muscles even if your patient doesn’t report any tension or tenderness. Better to be safe and find them now, than to be sorry later on.

Signs vs. Symptoms

It’s important to review signs and symptoms during our exam. Signs are those sore and tender muscles we discover through the exam process the patient wasn’t aware of. Symptoms are those sore muscles they point out to us. It’s critical to look for signs of wear, which are a good indication that there is disharmony in the masticatory system.

Remember what Dr. Dawson says?

When teeth and muscle war, muscle always wins. As a result, occlusal muscle disorders can often be diagnosed by observing wear and cracked teeth, even if the patient is not reporting pain or discomfort. Pain is a symptom, but signs always precede symptoms.

Another sign of muscle overuse is an increase of muscle mass. Think of a weight lifter. The more the muscles are used, the more they will bulk up. In patients, this increase most often exhibits as an enlarged masseter muscle. Over time, a patient who has developed a square jaw has a strong indication of muscle overuse, and oftentimes, the patient will report no pain in this muscle.

However, the indication of the bulkiness in this muscle should be a red flag that the muscle is being overworked. Even in the absence of pain, palpating the muscle will reveal tenderness, and I’ve seen patients literally flinch upon my palpation of a large masseter. Watching the patient’s eyes while palpating the muscles and you will usually see the eyes flinch if the muscles are hot.

One way to verify this overuse is to ask the patient if she has any history of clenching or grinding. Regardless of whether you see a muscle buildup, whenever you have a patient with a history of clenching and grinding, you should put on your detective cap. Start looking for the weak link in the system where the muscles are either breaking down or adapting to these stressors.

Verification Through Load Testing

As you are doing the load test, ask, “Do you feel ANY tension or tenderness in either jaw joint?”

If there is any positive response, then stop immediately to determine the cause and differentiate between an intracapsular or an occluso-muscle problem. To rule out the latter, a deprogrammer device should be used to open the back teeth and remove all contacts of the posterior dentition. Usually within five to thirty minutes, the muscles will relax and you can seat the TMJs. If pain is still occurring in the TMJs, then you need to start thinking intracapsular disorder and proceed with great caution.

Deprogramming hot muscles begins with a thorough exam, thorough history, and careful analysis of each muscle. For more information on occlusal muscle disorders, I recommend you review Chapter 24: Occluso-Muscle Disorders in Dr. Dawson’s textbook Functional Occlusion – From TMJ to Smile Design, which describes each muscle in detail and how to do a differential diagnosis.

Dr. Leonard Hess, DDS

Dr. Leonard Hess, DDS

Dr. Leonard Hess began teaching continuing education courses in 2005, and the topics include occlusion, smile design, treatment planning, preparation design, and practice integration of complete dentistry. He’s taught full-day continuing education courses at the American Academy of Cosmetic Dentistry’s national meeting, The Greater New York Dental Meeting, AACD National Meeting, Pacific Dental Conference, Ontario Dental Association meeting, and The Yankee Dental Conference. Dr. Hess also has taught courses in Japan, Germany, Poland, China, and Canada. Dr. Hess is currently serving as the Senior Clinical Director at The Dawson Academy. He also owns Union County Center for Comprehensive Dentistry in Charlotte, North Carolina.