In 1994, researchers in Adelaide published an extraordinary study in the Journal of Experimental Brain Research. Turker and colleagues inserted small electrodes into the biting muscles of volunteers. These electrodes were able to measure facilitation and inhibition of those muscles. The researchers then applied slow pressure to a tooth – simulating what would happen if the volunteer was biting through something hard. The measurements showed that slowly increasing pressure facilitated the muscle making it able to contract. The researchers then gave the tooth a brisk tap, simulating the situation where we suddenly bite something hard, like a seed or a stone. The biting muscles were immediately inhibited or switched off.
Chewing and biting turn out to be relatively subconscious activities. Since we don’t actually know how hard something is until we bite it, each tooth socket is filled with nerve sensors that tell our brain how much pressure is on the tooth. These sensors were stimulated by the increasing pressure (as would be the case if we were biting a nut or an apple) and they, in turn cause the bite muscles to fire. If the apple or nut turn out to be harder than we anticipated, the sensors detect more pressure and send more for more output from the muscles – we hardly realise it’s happening. If, however, we are chewing away and suddenly bite something hard and unexpected like a stone or seed, those same sensors detect a sudden increase in pressure and suddenly inhibit or switch off the bite muscles, preventing damage to the tooth.
Remember last time you nearly broke a tooth biting on something unexpected? Were just your jaw muscles affected? No, of course not. Likely your whole body withdrew from the insult.
Nowhere is it more important to realise that sensory input is linked to motor output, than in teeth.
All that subconscious control over our biting, chewing, kissing, talking takes an awful lot of sensory input and an awful lot of subsequent muscle control.
The disproportionate amount of input from the hands and mouth region shows up in the sensory homunculus.
If proprioception matters to the body, it matters most to the teeth. While much proprioception is processed at a local spinal level, all sensory information ultimately reaches the sensory lobe of the brain which has direct connections to the motor areas. The function of this sensory lobe has been well mapped and illustrates that a large area of the brain is devoted to processing sensory information from the mouth, lips and teeth.
Proprioceptive irritation to the mouth can cause severe muscle inhibition.
While most dentists are aware that a faulty bite can cause facial and jaw pains, most have no idea that the work they do in the mouth can also result in muscle weakness in almost any other area of the body.
If you are using proprioceptive muscle testing, eventually, you are eventually forced to look at teeth. Sadly, looking at teeth is problematic for reasons of patient preference and expectations, but if you are dedicated to working out the real reasons behind injuries and illness, and the reasons why some physical treatments just never work then you can’t avoid the inevitable. The upside is that nothing else will give you the satisfaction that comes from truly changing someone’s life.
Here are just a few examples:
Remember that our online and live training gives you everything you need to know about the dental causes of proprioceptive insult that cause nerve interference and muscle inhibition.