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Many of our patients present with pain. Dental pulp may be the source of pain in patients who have bacterial invasion of the innervated tissue in the tooth from decay. Pain can also come from masticatory muscles that become sore from repeated contractions.

Occlusal interferences have commonly been assumed to be the cause of masticatory muscle pain. As a result, many patients have undergone different dental procedures to help obtain a balanced occlusion with the hope of decreasing muscle pain.

Fortunately, many patients with masticatory muscle pain have been helped by different dental procedures. Occlusal appliances, equilibration, orthodontics, direct or indirect restorative options, and orthognathic surgery have been some of the procedures used to help patients achieve a harmonious occlusion with even intensity, bilateral contacts in vertical mandibular movements and anterior guidance in harmony with the envelope of function.

The problem is some patients do not report a decrease in pain with these treatment modalities and some will even report a worsening of symptoms. Many times, these patients are labelled as “high-stress” patients who continue to clench and/or grind teeth even after the occlusal has been perfected. In these scenarios, both the patient and the doctor become frustrated with the inability to reduce pain even though the occlusion looks perfect.

In these cases, it may be necessary to take a new approach. It would be helpful to think about which other issues could cause the muscles to contract beside occlusal interferences. Since our training is heavily tooth-based, the natural assumption is that the uneven tooth contact will cause increased muscle contraction in some patients. However, if we take a closer look at muscle contraction, there may be another source that we often overlook.

Dr. Mark Piper, an oral surgeon in St. Petersburg, Florida, has explored the role of the sympathetic nervous system in terms of pain in the head and neck region. Sympathetic nerve-based pain is commonly referred to as complex regional pain syndrome.1-6

Pain in the head and neck region can occur not only from occlusal interferences but also from a malfunction of the sympathetic nervous system. The sympathetic nervous system stimulates the flight or fight response in our bodies. The parasympathetic nervous system plays the opposite role and stimulates the rest/digest response in our bodies.

Stimulation of the sympathetic nervous system can cause vasoconstriction of most blood vessels along with muscle dystonia. Dystonia is a neurologic movement disorder in which sustained or repetitive muscle contractions occur.

Bruxism can be an example of sympathetically induced dystonia. Combining the decreased blood flow and the increased muscle contraction from sympathetic nerve inputs can begin to explain why some patients with a perfected occlusion continue to experience pain. Stimulation of the sympathetic nervous system can occur from injured temporomandibular joints, as well as from poor quality sleep.

Spear Resident Faculty member Dr. Jeff Rouse and I have been talking about sympathetically induced pain as a key point in helping patients with airway disordered breathing, as well as patients with structural changes in the jaw joints.

Treatment options can include treating the injured joint, restoring normal sleep patterns, medications and nerve blocking. The key is to remember that there may be reasons other than occlusal interferences when patients present with muscle pain that does not resolve with traditional occlusal therapy.

Jim McKee, D.D.S., is a member of Spear Resident Faculty.


1. Tinastepe N, Oral K. Complex regional pain syndrome. J Am Dent Assoc. 2015;146(3):200-2.

2. Parkitny L, Wand BM, Graham C, Quintner J, Moseley GL. Interdisciplinary management of complex regional pain syndrome of the face. Phys Ther. 2015; Available from:

3. de Mos M. Complex Regional Pain Syndrome : Practical Diagnostic and Treatment Guidelines, 4th Edition. 2013;180-229.

4. Fechir M, Geber C, Birklein F. Evolving understandings about complex regional pain syndrome and its treatment. Curr Pain Headache Reports. 2008;12(3):186-91.

5.van Rijn MA, Marinus J, Putter H, van Hilten JJ. Onset and progression of dystonia in Complex Regional Pain Syndrome. Pain. 2007;130(3):287-93.

6. Melis M, Zawawi K, Al-Badawi E, Lobo SL, Mehta N. Complex regional pain syndrome in the head and neck: A review of the literature. J Orofac Pain. 2002;16(2):93-104.