Why do we grind our teeth when we’re anxious?
In: Other
I’m a dentist who treats TMJ issues. The explanation for parafunctional habits, such as clenching or grinding, is a little complicated, but I’ll try to keep it simple.
We have two tempromandibular joints (TMJs) just in front of each ear. Our lower jaw rotates smoothly in those joints in a way that is determined by the shape of the joints, the muscles that connect the upper and lower jaws together and the nerves that control those muscles.
In a perfect world, when your jaw rotates in its physiologically ideal way, given your anatomy, at some point your upper and lower teeth will come into contact simultaneously, left and right, front and back.
Touch sensitive fibers in the gums feel that contact and tell the brain to shut down the muscles.
But, for various reasons, that simultaneous contact doesn’t happen for lots of people. A tooth on the back on the left side might hit just before the rest. It might be slightly tipped or rotated, either naturally or from having been moved from orthodontics. Maybe there’s a filling that’s too high. Lots of reasons.
Your brain wants all your teeth maximally together, so chewing muscles on the other (right) side will continue to fire and your lower jaw will do a little adjustment in its closing path to make that happen.
That’s usually OK, because there’s “wiggle room” built into the system to allow for small misalignments of teeth. We all have an adaptive capacity that keeps us symptom free most of the time.
If, however, the mismatch between jaw movements and teeth contacts exceeds our ability to adapt, symptoms can occur.
They might be teeth symptoms – excessive wear, sensitivity, looseness, chipping or fractures.
They might be muscle symptoms – sore, tired chewing muscles, limitations of jaw movements, even temporal headaches.
They might be joint symptoms – clicking, grinding or popping noises, jaws that lock open, painful opening or closing.
Or they might be parafunctional habits – clenching or grinding. That’s you brain’s heavy-handed way of trying to grind down that high spot and find a comfortable resting position for your jaw. This usually happens when we’re either sleeping, or perhaps focusing deeply on a task and our unconscious mind takes control.
Many patients have bite issues that normally fall within their adaptive capacity, and are usually just fine.
But if something reduces that adaptive capacity, such as illness or stress, these symptoms can reveal themselves. People float in and out of symptoms based on apparent stress, when stress is simply uncovering the real issue.
A generation ago, we believed that stress alone was the reason for teeth clenching and grinding. By the 1970s, we figured out that there was an underlying cause for these and other symptoms.
And it doesn’t take much to create problems for many patients. Discrepancies as small as 50 microns (Saran Wrap thickness) can mean the difference between comfort and pain for some.
That’s a lot of information, and there’s much more to it than this (how teeth behave in the function of chewing and treatment options, for example), but the main thing is that most TMJ issues, in the absence of trauma or degenerative conditions, such as arthritis, are fundamentally a mismatch between two systems that should be in harmony – the way the jaw moves, and the way teeth fit and work together.
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