A short post on posture/ergonomics in the dental setting and some notes on choosing dental loupes

Someone at work was asking me questions yesterday because her daughter is going through dental school and experiencing back and neck pain that is making it difficult to go about her daily life. She is understandably very upset and severely regretting her career choice. I will summarise the information that I have on the subject:

-I started by saying this is normal. I then changed that statement to: This is not normal, but it is common. Pretty much every dentist will experience neck and back pain in their career at some point. Pain is a sign that something in the body isn't as it should be. Just because something is common, doesn't mean we have to accept it as normal. Pain this early on in her career is a sign that something is seriously wrong and needs to be fixed asap.
-Back and neck pain is a sign of poor ergonomics. It is not surprising that this happens when you consider what it is we do. We work on very small objects to margins a fraction of a millimeter in a dark environment at the back of a cave flooded with water and filled with moving parts. Not only this, but a large portion of time we are doing this in reverse, looking through a small mirror on a patient that is stressed out of their mind. Is it then such a surprise that we put our bodies through stresses to be able to see clearly and perform good quality work?
-Neck pain can manifest as headaches. Neck and back pain can be debilitating. When we are in pain, all our body wants us to do is get out of pain. This involves removing us from the situation that is causing us pain. In some cases, this is a hand out of fire, a foot from a nail in the ground but in this case it is our livelihood that we are at odds with. It isn't something that is feasible to just quit and leave. The fear of pain may hold us to ransom, leading us to dread work at the start of the day and curse it at the end of the day. It doesn't need to be said what this mentality can do for job satisfaction. In fact, chronic pain is something that behind the scenes will cause many a dentist to retire earlier than they need to in a job they otherwise enjoy.
-Occupational neck and back pain is a simple cause and effect relationship. We overstress our bodies by bending and turning joints in directions they aren't meant to be moved and over stretching and working muscles. We fix ourselves in positions with our head leaned forwards that massively increases the weight on our spinal column. These stresses result in inflammation of the soft tissue and compression of the cervical vertebrae which causes the resultant pain. When we are young, our bodies are better at compensating but as we age, the pain may become unbearable. Conversely, when we are starting out in our career, the muscles that hold us in these awkward positions are undeveloped and we will experience a significant amount of initial pain. As these compensate and strengthen, this initial pain may reduce to a dull ache that may not even be noticeable as it may become the new norm. Thus, the common trajectory is severe initial pain which dulls down for years and is accepted till we age to a point where it worsens and leads us to an early retirement.
-The secret is to target behaviours from the start, before these compensating mechanisms take place. It can be done at any point of your career but later on may require more involved physical therapy which may be professional or self guided.
-The strategies involved are:

• Dilligence, posture will be self guided throughout your life. It's your body, you're in control. If you're slouching then sit straight. Sitting straight will place your skull over your spine in the position that places the least weight on the spine. 
• Good posture isn't something that starts and stops in the workplace, it is just as important to reduce stress on your body at home and on the go. I was given a good explanation in the past to imagine a string hanging from the ceiling going through the top of your skull suspending your head upwards. This would straighten your back due to gravity and let your spine dangle underneath. Stop slouching and lift your chin like a proud person and point your eyes towards the horizon. Straightening your back may feel very strange and unnatural especially if your muscles have compensated but as if you make it a habit then your musculoskeletal architecture will adapt and change. Have the same principles of sitting at a desk as you would have in a dental chair, the top of your computer screen should be a good distance away, your eyes in line with the top of the screen and the screen and font big enough so you aren't forced to lean forwards to read.
• Tuck your chin down, double chins are in fashion. The C1 segment is like a doughnut that the occiput of the skull (C0) sits on. Most of the flexion/extension i.e nodding of the head should happen between the skull and C1, The C2 segment is like the stick on the ground in a ring toss game. The C1 doughnut sits on this ring toss stick which somewhat limits the extension of C1/C2 joint. It is important to know how we are designed so we can use our body effectively. The C1/C2 joint is responsible for most of the rotation of the skull i.e saying no. All of the cervical spine joints are capable of flexion/extension to some degree but utilising the C1/C0 joint by tucking the chin down as much as possible reduces ligament strain and minimises the apparent weight on the spine.
• Tucking the chin down brings us part of the way towards our vision being directed towards the patient but the rest must be gained by turning your eyes downwards. This is something that is not intuitive because we are used to looking at things straight on but with the combination of both, we are able to see the working field with minimal bending of the cervical vertebrae
• Loupes are fantastically important for posture. Magnification and illumination to some degree allows us to see things larger and brighter (not necessarily clearer) and both of these will reduce eye strain. However, due to the optical of the loupes, there will be a focal zone behind and in front of which everything is blurry. It is of vital importance to design the focal zone at a working distance that forces you to sit straight. It is important that you are measured for custom loupes in the working environment i.e on a dental stool in front of a dental chair. Many reps will measure you anywhere and this may not be reflective of the environment you will be using the loupes in everyday. Ensure that the loupes company will allow a trial period in which if you notice that some of the specifications are off they will adjust the loupes at no extra charge. Loupes are a long investment and don't be afraid to spend a bit more if quality and service is improved. After all, how much is it worth to be out of pain and to have the ability to work for years longer?
• Loupes control your posture by forcing you eyes through a narrow area and forcing your head to a certain position which positions your spine to bring it to this position. If the loupes are improperly constructed then they can be more of a hindrance than a help. If the eyepieces aren't in line with your eyes, you may tend to want to look around the loupes and contort your head in such a way that they aren't in the way. If this is the case, you're better off with safety glasses. If there is not sufficient angle of declination i.e downward angle of the loupe lenses then your eyes will not be able to turn downwards and so your cervical spine will have to bend to allow a straight path of vision to the patient. In general, flip up loupes allow a steeper angle of declination than through the lens. If the working distance is too long, you may lean back to increase the distance between the patient and your eyes. If it is too short, you may raise the patient chair to bring them close to your eyes but as a result you may have to over bend your elbows to access or what is even worse, raise your shoulders (leading to upper back trapezius pain). You may also crane your head forwards resulting in the same issues previously mentioned. I believe it is better to be too long in working distance than too short but in reality, both are unacceptable. Is it too much to ask for things to be correct? Don't be afraid to refuse anything less than what is right.
• For measurement and in every day practice, when you are posturing yourself in a dental chair, start with the foundation. Feet firmly planted on the ground, legs apart at 45-60 degrees (wear pants). The seat of the chair should be slightly slanted downwards so your buttocks are slightly higher than your knees. Your back should be lightly resting against the backrest (tilt the rest forwards if you have to lean back into it), and your back should be straight but relaxed (not rigid like people do right after you tell them they're slouching). Your shoulder should be down and slightly tucked back with your shoulder blades bulling slightly towards each other. Your elbows should be at about 90 degrees with no arm muscles tensed. This should bring your hands to about the level of your belly button. The patient chair should be reclined to this level and you should position your chair bringing you as close to the patient headrest as possible. Measurement should be taken from your eyes with your chin tucked down to the supposed position of the central incisors and to the molars. This will give you the range in which you want things to be in focus.
• Depending on the magnification of the loupes, the working distance range will be larger (for smaller magnifications) or smaller (for higher mags). Generally it will be listed as one number and you should have this number to be the distance to about the premolar region (because there will be a focal zone before and after this point.
• Once you have your loupes, ask one of your colleagues to take a photo of you working, when you aren't aware of them. This will show you what your posture will be like in every day practice. If it is still wrong, either you need to focus more on breaking bad habits or your loupes need adjusting. If your loupes allow you to have had posture habits then most likely they need adjusting anyway. They can be used as a diagnostic tool for poor posture as well as being the cause for bad posture if improperly adjusted.
• Physical therapy is something I don't know a lot about but naturally it would involve stretching to improve flexibility and muscle strengthening to improve postural muscles. Slouched posture tends to result in back muscle weakening and front muscle shortening. What I do know is that physical therapy must be taken slow and steady. Muscles, ligaments and joints will improve only when they do and this is something that can't be rushed. If we rush physical therapy then it will result in muscle tears with more pain and inflammation. I hear yoga/pilates is quite good for developing strength and improving flexibility but I am yet to try it out myself.

Tell your staff to let you know when your posture is failing and do the same for them. Back and neck pain is an occupational hazard in dentistry and no one wants to go into forced early retirement. Pain makes us cranky, it reduces our tolerance for errors and increases our stress level. Dentistry is a team effort. If we all put a bit more effort into looking after each other and get over the fear of providing and receiving criticism I'm sure we'll all reap the rewards as we constantly strive to improve.