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The two popular news articles discuss increased rates of Temporomandibular joint dysfunction or "TMJ" symptoms and broken teeth reported in the US as well as the (potentially bi-directional) connection between sleep loss and bruxism, but the second one also says the following:

First, an unprecedented number of Americans are suddenly working from home, often wherever they can cobble together a makeshift workstation: on the sofa, perched on a bar stool, tucked into a corner of the kitchen counter. The awkward body positions that ensue can cause us to hunch our shoulders forward, curving the spine into something resembling a C-shape.

If you’re wondering why a dentist cares about ergonomics, the simple truth is that nerves in your neck and shoulder muscles lead into the temporomandibular joint, or TMJ, which connects the jawbone to the skull. Poor posture during the day can translate into a grinding problem at night.

Is there any relationship between poor posture during the day and problems with bruxism and/or TMJ, or is this just idle speculation? The linked Wikipedia article says:

TMJ dysfunction is commonly associated with symptoms affecting cervical spine dysfunction and altered head and cervical spine posture.23

23Effectiveness of Manual Therapy and Therapeutic Exercise for Temporomandibular Disorders: Systematic Review and Meta-Analysis

but that paper seems to have a negative result. It is hard for me to understand exactly what the paper does say, so I'd like to ask here:

Question: What is the relationship (if any) between poor posture during the day and problems with bruxism and/or TMJ, or is this just idle speculation?


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It is a very interesting question!

So before everything, it is important to understand what is Temporomandibular joint and its components.

The temporomandibular joints (TMJ) are the two joints connecting the jawbone to the skull. It is a bilateral synovial articulation between the temporal bone of the skull above and the mandible below; it is from these bones that its name is derived. This joint is unique in that it is a bilateral joint that functions as one unit. Since the TMJ is connected to the mandible, the right and left joints must function together and therefore are not independent of each other. Reference

Other components, apart from articular surface of temporal bone and condyle, include various ligaments as well as main and accessory muscles of mastication. Names of all the muscles and ligaments This image will explain the relationship of TMJ with major masticatory muscle enter image description here Reference

Now,

Many practitioners have speculated that poor posture may have a negative effect on temporomandibular, or TMD, symptoms and treatment outcome.

The most common of them is forward head posture. enter image description here Reference

With this posture, the head’s center of gravity is forward of the spine’s weight-bearing axis, which increases the strain within the posterior cervical muscles, ligaments and apophyseal joints.

It has been demonstrated that cervical muscle activity influences masticatory muscle activity.Practitioners have theorized that the additional demand that is placed on the posterior cervical region by the forward head posture alters the masticatory system so that people are more susceptible to masticatory muscle strain, spasm and pain.

Reference Also,

The guidelines of the American Academy of Orofacial Pain pointed out a correlation of TMD and cervical spine. The cervical spine is intimately related to the cranium and masticatory system via specific joint articulations, muscle attachments, and neural and vascular innervations and the relation of postural balance among them is of fundamental importance to maintain the functionality of the system formed by these structures. Reference

The whole mechanism is beautifully explained in this article-

The biomechanical complexity of body posture derives from the functional integration of several body segments: when there is a change in any biomechanical subunit, a refinement of the postural control systems will necessarily occur. The muscle groups of the stomatognathic system belong to the cervical muscular chain. Considering that the musculoskeletal system is composed of several such muscular chains that are integrated with one another, any disturbance of a body segment will lead to a reorganization of other segments.This fine tuning of posture control leads to body segment adaptation and realignment, whether physically near to or distant from the TMJ.Reference

Also apart from forward head bending this same article aims-

To identify the relationship between anterior disc displacement and global posture (plantar arches, lower limbs, shoulder and pelvic girdle, vertebral spine, head and mandibles)

Note that anterior disc displacement (in which there is clicking heard on opening and/or closing) is a common TMD.

Although it is not possible to positively state a cause-effect relationship, our data at least verify the mutual existence of global body posture deviations and TMD.

Infact, for treatment of TMD there are useful training programs to correct posture. Reference

Concluding I found an interesting image, stating that poor body posture can influence even teeth alignment or the occlusion!Reference enter image description here

Hope I have satisfactorily answered your question!

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    I have my exams starting from tomorrow! But I found this question very interesting hence couldn't wait for my exams to get over. I got so many interesting articles and studies. Once my exams get over I will edit the answer to make it more informative for the future references!
    – Ojasvi
    Sep 13, 2020 at 10:01
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    Thank you for your speedy answer! Good luck on the exams, get back to work! If you update please ping me again :-)
    – user16606
    Sep 13, 2020 at 10:03

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