During the course of the year, we are often challenged by orofacial pain patients that don’t respond to first line therapies and present with histories that make it difficult to understand why they are in trouble. Having just returned from the Annual American Academy of Orofacial Pain Scientific Meeting, I thought I would share some of the more noteworthy presentations that may assist us in the assessment and treatment of orofacial/TMD pain patients.
1. Ongoing Laboratory research has revealed that persistent inflammation in the neck can predispose patients to orofacial pain (including toothache complaints) and TMD symptoms following jaw opening during a dental visit. The amount of time that the mouth has to be opened to prompt jaw/orofacial pain symptoms has not been quantified, but the symptoms that develop may become persistent in nature if the neck is not identified as the source of the onset, and treated.
2. Heavy nicotine users and patients that have REM sleep deprivation (the part of sleep when the nervous system is repaired) have been found to be poor responders to treatment for muscle-based TMD problems. Both REM sleep deprivation and nicotine appear to lower the threshold of the trigeminal system, giving rise to pain symptoms that are more acute than the physical exam suggests should be present. REM sleep deprivation may be the result of other chronic pain problems throughout the body, such as back and neck pain.
3. Patients with persistent TMD and orofacial pain complaints have been shown to have less heart rate variability than patients without these symptoms. Heart Rate variability represents the time between each successive heartbeat, and this time period should be variable between all beats when there is normal balance in the autonomic nervous system. TMD patients have been shown to have lower heart rate variability, likely as a result of hyper-vigilant personalities that drive the sympathetic nervous system to be in a sustained fight-or-flight mode. The heightened sympathetic drive puts muscles at risk for hyper-excitability and pain.
4. Many of our TMD patients exhibit fast-paced chest breathing tendencies. As a result, Carbon dioxide is removed from the blood stream, creating a higher body pH. This higher pH, in turn, activates the sympathetic nervous system and drives more muscle tension and lower nerve thresholds. Therefore, one of the key therapies in this patient population has been to change respiratory patterns to bring the breathing into the diaphragm and slow the pace. When practiced, this treatment strategy has lowered TMD pain consistently.
I believe these insights will be helpful assessment and treatment of orofacial/TMD pain patients. I welcome your comments.
