May 16, 2016
by Mahmoud Zaerian, DC, CSCS, BA (Kin)
When it comes to pain and dental professionals we know two things. One, pain is almost inevitable, due to the taxing nature of the job on the body; and two, that common imaging studies (X-rays and MRIs) often do not show significant findings that would explain the experience of pain. But the pain is definitely real and felt – so how does one go about dealing with and addressing this pain within the body?
This is an important question for dental professionals to answer, as pain has almost become synonymous with the dental profession. However, this isn’t an easy question to answer. I have written before for Oral Health about the multi-dimensional nature of pain and the many factors that lead to it as well as the multi-dimensional nature of the body’s function and the many dynamics that contribute to the manifestation of pain in the dental professional.1 In this article, I will discuss one common cause and an approach that can be followed that may lead to reducing the pain in your body.
Myofascial trigger points, as first described in 1843 by Froriep, and made famous by Travell and Simons in 1942, are a common contributor to the development and manifestation of pain in the dental professional. Travell first described a trigger point as “a hyperirritable spot in the skeletal muscle that is associated with a hypersensitive palpable nodule in a taut band. With compression, the painful point can cause referred pain, referred tenderness, motor dysfunction/weakness and autonomic phenomenae”.2
Why is this an important topic to discuss with dental professionals dealing with pain?
There are two reasons, both very important concepts to understand. The first is that although we call it a “myofascial” trigger point and the name implies the problem lies within the muscle and fascial/connective tissue, those tissues are non-noxious tissues. They aren’t capable of signalling pain in the body, so to imply that these tissues are the pain generators is just inaccurate and lazy thinking. Nociception, or the noxious stimulation through the body signaling to the brain, is only generated in the nervous system. Therefore, trigger points are more accurately due to neural tissue and not muscle or connective tissue.3 This begins to make sense since the majority, if not all, of the known trigger points in the body coincide with where neural tissue innervates muscle and connective tissue. In reality what we are feeling as the palpable nodule and sensitive points, are neural tissues that have become sensitized. Again, this is important to understand because approach to care changes based on this finding.
Because nociception is originated in neural tissue, this also explains the referral patterns that will be exhibited with typical trigger points.4
The sensitization of the neural tissue is a representation of decreased depolarization potential within the affected neural tissues, which means that activation takes place with a reduced amount of stimulation; they are hyperaroused.4
Thus, the pressure that produces pain in the body isn’t due to actual muscle or connective tissue pathology, but rather sensitization of neural tissue, whether cutaneous nerve, nociceptive fibres or even the nerves of the nerve trunks themselves (nervi nervorum).5 Why does this happen?
This brings us to the second reason that it is important to understand trigger points and their resulting pain as dental professionals; this reason relates to posture. You have likely heard it from many; including me in the previous five articles I have written for Oral Health, that ones posture in practice may be the cause of many of the ailments that occur.6
Any position that you put your body in produces a certain degree of tension and puts a certain degree of force through your body. The various muscles that have to sustain that tension eventually tire and need rest. This rest isn’t given, and as a result there is alteration in the chemical environment in these tissues. It is this alteration in the chemical environment that produces that peripheral sensitization of the neural tissue and triggers the pain response that was discussed above.
I have spoken at the Ontario Dental Association conference in the past about the use of ergonomic equipment. Although ergonomic equipment certainly does not harm and could potentially help, it doesn’t eliminate the problematic factor: the prolonged static posture. As long as you are maintaining a static posture or engaging in repetitive movements in a given area, the tension in the specific tissues will be above and beyond what it can handle and the formation of the peripheral sensitization and alteration of the chemical environment will happen. This, however, isn’t the most important take away point. Active trigger points are a source of peripheral nociception that will eventually induce central sensitization.7
A barrage of nociceptive activity in the periphery has the ability to induce maladaptive neuroplastic alterations in the dorsal horn of the spinal cord – the phenomenon of central sensitization. Mechanisms involved in central sensitization include a lowered activation threshold for excitatory neurons, reorganization of spinal cord neurons and new synaptic connections. Furthermore, sustained input will eventually lead to expansion of pain patterns along dermatomes (areas innervated by the same nerve). This is important because what it leads to is not only a pain in the body originating due to the local chemical changes (sensitization of peripheral tissues) but also alterations at the segment that coincides to that area causing changes to areas of common innervation. This will contribute to fear of movement, muscle disuse, weakness and dysfunction. This creates the negative feedback loop of trigger points.
There is also research to show that those dealing with trigger points leading to central sensitization have an abnormal stress response as indicated by highly activated sympathetic and hypothalamus-pituitary adrenal (HPA) systems.8,9
TABLE 1. Trigger Point Therapy
** be mindful that if any discomfort persists to discontinue and seek a professional near by to evaluate your discomfort.
The bad news is that for most, there isn’t going to be a change in your work habits so trigger points and the systemic change in the body and the nervous system will be there and this will contribute to your pain. The good news is that for most of you, the pain that has developed due to neural changes due to the formation of trigger points can be addressed and improved so that you don’t have to suffer through pain.
The best modality that is available to us to deal with creating changes in the nervous system for long existing pain due to trigger points is through the proper and effective use of acupuncture with electro-stimulation. The insertion of an acupuncture needle within an active trigger point causes an almost automatic change in the biochemical milieu improving peripherally sensitized neural tissue. Utilizing electro-acupuncture to stimulate the segments affected by central sensitization will enhance the reduction of pain.
As dental professionals, there are many things you don’t have control over, like your dental posture and many hours in a sustained posture or repetitive motion, however there are aspects that you do have control over and that you can impact, and trigger points are now one of those areas.
There are approaches you can do individually to improve perfusion in the area of trigger points. The use of balls and rollers do help. In the pictures below, I show how you can use a roller or a ball in some of the areas of your body. In a new Dental Manual, along with demonstrating proper exercise execution, I go over the use of balls and foam rollers to provide relief from trigger points.
For information about the Dental Manual, email me at firstname.lastname@example.org or call (416) 837-4065.OH
Dr. Mahmoud Zaerian is a practicing chiropractor and neurofunctional sports practitioner in the city of Toronto. He has been in the health field for over 15 years working with many of our Olympic athletes including our Women’s Olympic Hockey team and Gymnastics Canada. He has spent the last eight years researching and working with dental professionals to restore health and pain free function in their body. Dr. Zaerian has written several articles on maintaining the health of the dental professional as well has spoken at the Annual Spring Meeting in Toronto and has been asked to speak at the California Dental Association Annual Meeting in Anaheim. He currently is one of the instructors at the McMaster University CMA Program, and has created The Dental Manual, a comprehensive written and video manual for dental professionals for restoring and maintaining health in their body. The Dental Manual includes video instructions and correct exercise execution as well as guidelines for an integrative approach to the health of the dental professional.OH
Oral Health welcomes this original article.
1. Zaerian M, The Big Picture of Low Back Pain. Oral Health Journal. 2015
2. Travell and Simons, Myofascial Pain and Dysfunction, The Trigger Point Manual. Volume 1. 2nd Ed, 1999. pp 11-86
3. Jay P. Shah and Juliana Heimur, New Frontiers in the Pathophysiology of Myofascial Pain. The Pain Practitioner. 2012
4.Shah J., et al. Uncovering the biochemical milieu of myofascial trigger points using in vivo microdialysis: An applicaton of muscle pain concepts to myofascial pain syndrom. J of Bodywork and Movement Therapies (2008) 12, 371-384
5. Arendt-Nielsen L, Graven-Nielsen T. Deep tissue hyperalgesia. J Musculoskeletal Pain. 2002;10(1/2):97-119.
6. Valachi K and Bethany Valachi, Mechanisms leading to musculoskeletal disorders. Journal of Amer Dent Ass, Vol. 134, No 10;1344-1350
7. Ibarra J., et al. Latent myofascial trigger points are associated with an increased antagonist muscle activity during agonist muscle contraction. The Journal of Pain. 2011;1282-1288.
8. Wall PD, Woolf CJ. Muscle by not cutaneous c-afferent input produces prolonged increases in excitability of the flexion reflex in the rat. J Physiol. 1984;356:443-458
9. Yoshihara T., Shigeta K., Hasegawa H., Ishitani N., Masumoto Y., Yamasaki Y. Neuroendocrine reponse to phsychological stress in patients with myofascial pain. J Orofac Pain. 2005 Summer; 19(3):202-208
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