Think of the soft tissue (e.g., fascia & skin) covering the bones of the skull as a balloon. When you grind your teeth down, it is as if you're taking air out of the balloon.
When this balloon deflates, it crushes the skull, which in turn crushes the brain and causes cognitive and neurological issues over time.
In general, we as a society like to call this process 'aging.' But if you grind down your teeth faster, you 'age' faster. The good part is you can reverse the process by using the same physics in reverse, i.e., you 'add' height back to the teeth.