Four handed dentistry has definitely led to some ease in practice and an increase in efficiency. However, it also has impacted the dental professional’s long-term health and well being. As a dental professional there is a requirement for precision, focus and unorthodox body positions. This combination may lead to prolonged sitting and standing positions in very constrained postures.
I have spent time in previous issues looking at how the profession impacts the health of your low back and neck and how it may lead to not only reduction in productivity but also more importantly how it may diminish the quality of life.1-3 Although there have been a lot of advancements through technology with the implementation of tools and machines to reduce the effects of the profession, there has been little reduction in time spent in pain and the experience of being worn out.
In this issue of Oral Health I will discuss the missing link in what ails the musculoskeletal health of the dental professional and the implications on long term well being.
Human beings are hard-wired to achieve a stable, upright posture by four years of age. Our bones that float about in the tissues, such as our spine, contribute to that by developing the curvatures to maintain an upright posture.4 Due to television, soft couches, chairs, desks, computers, driving in cars, and for dentists the upwards of eight hours spent hunched over in a dental chair, the thoracic spine slips into a greater kyphosis, which is a greater rounding of its natural curve5 (Figure 1). If we were to only look at the spine, which would be a reductionist approach but one that is demonstrative of what is occurring in our body, as one curve in the spine changes the others that have to compensate for it to maintain the upright posture. Therefore, any alterations within your thoracic spine will lead to alterations in the lumbo-pelvic and cervico-cranial posture, as they are all interrelated as links in a chain. They influence each other in dysfunction as well as in rehabilitation. It has been shown that a significant association exists between a reduction in mobility of the thoracic spine and the presence of patient-reported complaints associated with neck and low back pain.11 In one study, Cleland showed that in select patients, the utilization of thoracic spine manipulation was sufficient to provide a successful treatment for patients with neck pain.4
As a result of the increased thoracic kyphosis, biomechanical overload and functional adaptations can occur in various sites of the locomotor system. In the kyphotic posture the sternum and the symphysis pubis affect not just those joints themselves but also key muscles such as the diaphragm affecting such basic functions such as respiration.6 Upper thoracic dysfunction, the area of your thoracic spine that is most commonly dysfunctional with the most susceptible segments being the fourth thoracic vertebra and eighth thoracic vertebra, will lead to use of auxilliary muscles of respiration such as scalenes and upper scapula fixators such as the levator and upper trapezius, and not the natural muscle of respiration, that being the diaphragm. This has been shown to increase the occurrence of dyspnea as well as decrease forced vital capacity and forced expiratory volume in one second.7 The hyperkyphotic thoracic spine in dentists is associated with dyspnea and ventilatory dysfunction, which is a source of the increase in the experience of fatigue in the body. This reduced oxygen flow to the body and brain is most common in the seated position that is assumed by the dental professional. Thoracic spine dysfunction is very much a silent killer, in that T4-T8 dysfunction is a common source of muscle imbalance, trigger points, joint dysfunction and faulty movement patterns all being asymptomatic. The most common sites affected are the neck, TMJ, shoulder, arm and even lower back regions. This is also a main reason why treatment for various aches and pains in the above mentioned areas provides no resolution. Treatments aimed at the site of the symptoms are bound to fail.
When there exists a thoracic spine dysfunction, which there is in a hyperkyphotic thoracic spine, extension is restricted and a chain effect occurs in the body. Hyperkyphosis of the dysfunctional thoracic spine leads the shoulder forward into a rounded and internally rotated position.6 This causes pectoral and internal rotator tightness leading to increased stress on the glenohumeral joint. This stress translates the humeral head anteriorly and superiorly and alters scapulohumeral rhythm, reducing mobility in arm elevation and predisposing to mechanical impingement of the subacromial space, anterior labrum instability and rotator cuff tendinosis.8 There also develops a chin protrusion because of a forward head posture causing hyperextension at the C0-C1 joint leading to the alterations in the function of the TMJ. The protruding chin leads to a decrease in extensibility in mouth opening, which alters the biomechanics of the TMJ increasing stress on the disc.9
All of this occurs in your body, unbeknownst to you unless a symptom has developed for you to be mindful of and treat. Your body will continue to do what you ask of it, so when you reach to lift something overhead, instead of extending through the middle of your back, you end up increasing the mobility in your lumbar spine leading to low back symptoms and long term impacts on your lumbar discs. Below is a list of the functional adaptations that may occur secondary to thoracic spine dysfunction and the relationship to the areas of biomechanical overload.
As a dental professional you don’t have much of a say in the implications of your profession on your body; however, the longer nothing is done about it, the longer the rehabilitation will take and the more aches, pains and disability you will have in the long run, including the enjoyment that may occur away from practice. Therefore, rehabilitation of the upright posture is fundamental to optimization of function in the locomotor system. Neurological programs for maintenance of the upright posture are “hard-wired” into the central nervous system. The human brain creates an imprint for how to hold the body up so that so there is no engagement of active thought. In other words, what that means, is that rehabilitation of the thoracic area is of central importance, both biomechanically and neurophysiologically.10
The intentions of the series of articles I have written over the last three years has been to shed light on how the dental profession impacts the musculoskeletal system and to bring awareness to its long term implications as well as provide some insight on the actions that can be taken at any point in time to not only improve the longevity of your career but also the quality of your life. I have spent six years working with dentists and studying dentistry and how it impacts the body. This has given me the impetus to create an instructive manual on how to provide rehabilitative and corrective exercises that impact your long term health as a dentist. Consider it to be your very own home specialist! Included with the manual that will guide you through the rehabilitative and pre-habilitative exercises, will be a video of me taking you through the exercises one by one just like you would if you were with a health professional. This will get you on track to deal with the chronic aches and pains you experience on a daily basis, and also reduce the impact on your finances when having to receive long term care for recovery. Please email us at: drzfocusitc.ca for information on the manual.OH
Dr. Mahmoud Zaerian, has been in the health field for over 13 years, spending some of that time working with the city’s top amateur athletes and national Olympians. Dr. Zaerian graduated from the Canadian Memorial Chiropractic College with his doctrine in chiropractic, York University with a Kinesiology degree and McMaster University with a certification in Contemporary Medical
Acupuncture. He is currently on board as one of the instructors of the McMaster Acupuncture Program. Dr. Zaerian is the owner and director of FOCUS Integrative Therapy & Conditioning, an advanced integrative facility, providing sound education and focused care in the conditioning and therapy of those committed to their ongoing health and wellness. Dr. Zaerian is scheduled to speak at the 2013 ODA Conference, and can be contacted at drz@focusitc.ca or at the clinic (416) 837-4065.
Oral Health welcomes this original article.
REFERENCES
1. Zaerian M. Musculoskeletal Disorders and the Impacts on the Dental Professional. Oral Health Journal. Feb 2009 64-66.
2. Zaerian M. The Art and Science of Low Back Health. Oral Health Journal. Sep 2009 78-80.
3. Zaerian M. Neck Pain: A scientific look at the Dentist’s neck! Oral Health Journal. Nov 2011 53-56.
4. Kolar P. Facilitation of agonist-antagonist co-activation by reflex stimulation methods. In: Liebenson C. Rehabilitation of the spine 2nd edition. Baltimore: Lippincott/Williams and Wilkins. 2007.
5. Norlander S, Nordgren B. Clinical symptoms related to musculoskeletal neck-shoulder pain and mobility in the cervico-thoracic spine. Scand J Rehabil Med. 1998;30:243-251.
6. Liebenson C. Self-treatment of mid-thoracic dysfunction: A key link in the body axis. Part 1: Overview and assessment. Journal of Bodywork and Movement Therapies. April 2001.
7. Di Bari et al. Thoracic kyphosis and ventilatory dysfunction in unselected older persons: an epidemiological study in Dicomano, Italy. Journal of American Geriatric Society. 2004 Jun;52(6):909-915.
8. Janda V, Frank C, Liebenson C. Evaluation of Muscle Imbalance. In: Liebenson C. Rehabilitation of the Spine, 2nd edition. Baltimore: Lippincott/williams and Wilkins, 2007.
9. Skaggs C, Liebenson C. 2000 Orofacial Pain. Topics in Clinical Chiropractic 7:43-50.
10. Hodges PW, Jull GA. Motor relearning strategies for the rehabilitation of invertebral control of the spine. In: Liebenson C. Rehabilitation of the Spine: A Practitioner’s Manual, 2nd edition. Baltimore. Lippincott/Williams and Wilkins. 2002.
11. Liebenson C, Winchester B. A key link in the locomotor system: The upper-thoracic spine. Dynamic Chiropractor 2011 Jun:29.
