Not just posture: causes of musculoskeletal pain
Khalil Hussein discusses musculoskeletal pain in dentistry by assessing the potential causes in daily work life
Perfect posture does not exist, and even if it did its perceived importance would have little significance compared to what was once thought.
There is currently no standard definition of what ‘good or bad’ posture is, and even less evidence pointing towards ‘bad’ posture playing a significant role in causing musculoskeletal pain (Barrett et al, 2016; Damasceno et al, 2018; Ettinger et al, 1994; Gay, 1993; Grob et al, 2007; Grundy and Roberts, 1984; Lederman, 2011; Richards et al, 2016).
Poor posture is likely caused by aberrant joint and tissue health, habit, and mental frame of mind (Barrett et al, 2016; Damasceno et al, 2018; Gay, 1993; Richards et al, 2016). It is, therefore, a symptom of deeper underlying issues rather than a significant cause of back pain. Tissue and joint resilience, joint mobility, movement habits, central nervous system health, and pain education play a more important role in preventing pain and injury (Coenen et al, 2014; Glasgow et al, 2013; Moseley, 2011).
In this article series we will explore the various factors that contribute to musculoskeletal pain in dentistry. The issues covered include:
- The science of pain
- Pain and injury from working as a dentist
- Postural tolerance
- Movement variation
- Stress and the psychology of pain.
The science of pain
Pain is a multifactorial experience that occurs for more than just physical reasons (Figure 1). Pain is a response to threat, perceived or actual (Butler and Moseley, 2013) – an output of your brain in response to the complex interaction of several factors. Furthermore how you think about pain, how you think about yourself and even your expectations about future threat or pain can all trigger different responses from the body (Rhud and Meagher, 2001).
Afferent physical information travels up the spinal cord into your thalamus. From here it is processed along with emotional factors, previous experiences, and predicted outcomes.
If the body deems all of this information to be an issue, pain will be elicited (Butler and Moseley, 2013; Chapman, 2008; Chapman, 2010; Christensen et al, 2017; Lederman, 2011; Moseley, 2011; Rhud and Meagher, 2001).
In many ways, pain is unique to the individual (Guenther, 2016).
This is produced to elicit a behavioural response; much like hunger causes us to eat, pain causes us to behave differently in response to threat.
For example moving your hand away from a hot stove to avoid damaging it.
It is for these reasons therefore that focusing on posture and ergonomics will not eliminate pain.
These do play a role, albeit a much smaller one than we had previously believed. If it was simply due to these factors, we would have eliminated back pain with posture braces and ergonomics chairs.
Musculoskeletal pain in dentistry
Currently, musculoskeletal pain is the biggest cause of insurance payments and early retirement in dentistry (Burke et al, 1997). Dentistry also contributes to an overwhelming amount of long-term pain (Burke et al, 1997; Hayes et al, 2009; Jones and Forsythe, 2005).
Highly stressful dental environments contribute to this substantially, because mental and emotional stress have a very large impact on pain generation (Butler and Moseley, 2013; Chapman et al, 2008; Chapman, 2010; Hirata et al, 2011; Lederman, 2011; Moseley, 2011; Rhud and Meagher, 2001; Van Eerd et al, 2016; Yarnitsky, 2010).
To reduce the likelihood of injury or pain, you need to prepare your body for the physicality of your job, akin to a professional athlete preparing their bodies for a marathon. If you require your neck to spend most of the day looking down, then you need the joint capsules and posterior neck muscles to be as strong and flexible as possible.
If you require your wrists to repetitively flex and extend under load, then they need to be as strong and flexible as possible. When load is placed on the body, it responds by adapting, which can be good (strength gain from exercise) or bad (osteoarthritis/repetitive strain). In addition we are subjected to the load of gravity every day and the activities we do can have a significant impact on how this adaptation occurs.
Increasing chances of injury
When the capacity of a specific joint/tissue is less than the load, trauma will occur and, as a result, aberrant tissue changes will occur (Mann et al, 2011). In most cases, these tissue changes are small, but they accumulate due to the repetitive activities most of us do daily.
These tissue changes accumulate (along with normal age-related changes) over months and years, and can lead to poorly adapted joints/tissues. Poorly adapted joints and tissues have much less capacity to deal with the stressors that we place on them. Without this ability to deal with stress, the chances of injury and pain become higher, so the cycle perpetuates.
For example, a dentist may spend 10,000 hours over a career in a primarily seated or sedentary position. This time spent not moving the joints of the spine accumulates, and the body adapts to become better at not moving (Figure 2).
Your tolerance to a certain posture comes down to your capacity to handle the stresses placed on your body. Too much stress beyond capacity will often lead to pain and injury, hence why changing your ergonomics can help with pain. It helps to avoid things you are not able to withstand.
However, this is not the complete solution towards preventing injury and pain, as spending too much time in one position itself causes issues, whether or not that position is ergonomic.
Being a dentist often involves scenarios where a more awkward approach to treatment can occur – the dentists must adapt to the patient at hand and this can often be for prolonged periods of time. Ideally, the patient should be adapted to the practitioner; however, this is not always possible, especially since every patient has different anatomy and possible restrictions to movement (for example, ‘do not recline’ patients).
Every dentist also has their own limitations in mobility, fine motor skills, and strength, which can influence working posture; hence, it is better to prepare yourself to work outside your comfort zone.
Only allowing yourself to remain in certain ergonomic postures will reinforce your weakness outside it.
By never moving beyond your safe zone, you put yourself at risk of injury when something occurs that forces you beyond your capacity. Moreover this includes postures and positions outside of work in your normal life.
Spending 40 hours a week in a mainly seated position with limited movement of the spine and other joints will cause an adaptive process that will lead to a loss of mobility over time (Figure 2).
Research says it takes more than one hour of exercise per day to counteract sitting for eight hours (Ekelund et al, 2016), and that is focused on office workers who do not need to hold a drill for 20 minutes and peer into someone’s mouth at an awkward angle. The best approach is to improve your capacity and overall mobility. Several exercises can serve as a starting point for the neck, visit bit.ly/2WUAIXn for a list of instructions.
Improving mobility and capacity is not a one-time process – it takes time, consistency and gradually exposing the body to greater stress over time. The acute stress elicits progressive adaptations not only in your central nervous system, but also within the tissues/joints themselves.
Above all this is where prevention and cure become a single entity.
With your new-found capacity and mobility, you are able to handle more stress. This therefore regulates and reduces your bodies threat and pain response (Chapman et al, 2008; Yarnitsky, 2010; Goldberg, 2008).
When looking at musculoskeletal pain in dentistry, we are aware of a multitude of factors in its development.
Of those, the most important is capacity to deal with stress/load, which includes mental, emotional, and physical stressors.
The best place to start if you are suffering is to find a clinician educated in all of these issues and to further your own understanding of what needs to be done to avoid and eliminate musculoskeletal pain.
For article references, email [email protected].
Exercises for the relief of neck pain
Download a PDF of this instructional guide by visiting bit.ly/2WUAIXn.