Limbic System

60% of all sensory input that comes into the body enters and is filtered through the Trigeminal Masticatory System (your jaws & teeth). This input is then sent to an area of the Mid-Brain called the Limbic System. The primary function of the Limbic System is to filter information and control emotions and behavior. As you can imagine, a person in pain with a small accommodative capacity and narrow goal posts because of the pain and an overloaded Limbic System can perpetuate many negative hyper-emotions such as hostility, anger, and crying. This is why many patients with TMD are coined in the medical profession as “crazy”…they are not crazy, they are in pain and have been for years! Their Limbic System is on overload and has to dump somewhere in order to survive.

Many times we lash out at loved ones or an innocent bystander when they weren’t the cause of our anger or problems at all. The kids not getting up in time, the car not starting, hitting every red light in town, and people driving too slow made you late for work which upset your boss and also got you behind all day which made you work twice as fast so you made mistakes which upset your boss again which made him have to counsel you which made you mad. Sound familiar? Now, you leave work, go to the grocery store, buy a jug of milk, have to wait behind 10 people in line, and now you have had it! You yell at the innocent high school kid checking you out at the cash register because you had to wait to buy your jug of milk. Was any of this his fault and did you really mind waiting in line? No! But, it was all of the other negative stuff that accumulated all day long that had nothing to do with the grocery store clerk that made you fly off the handle. That’s an example of an overloaded Limbic System…it had to dump somewhere before you went crazy, and it happened to dump right in the lap of the innocent grocery store clerk. Sound familiar? This happens to all of us. The smaller our accommodative capacity, the faster our stress bucket overflows and has to dump!

Many times, we hear our patients and other professionals say that stress causes TMD. In fact, stress is not a cause, but it can certainly exacerbate an underlying condition that may be otherwise dormant. Many patients and professionals also think that grinding (bruxism) causes TMD. In fact, I always have patients say to me, “Doctor, I don’t even grind my teeth, so why am I in so much pain”? The answer is that every time you swallow, which is 2,000 times per day, your lower jaw (mandible) swings on the wrong path of closure, and the teeth come together incorrectly causing muscle spasm causing pain. My other good friend and mentor, Dr. Clayton Chan, always says, “Keep the main thing the main thing”. Here is the “main thing” for you to absorb. Misaligned teeth bring about misaligned joints causing the joints to exist in a pathological position which, in turn, causes the lower jaw to be in the wrong position, which causes it to close on the incorrect path, which causes muscles to spasm which causes pain.

Two Causes of Pain

• Lower Jaw / Mandibular Position (where it rests and how it closes)
• Micro-occlusion (how the teeth come together)

So, why does this happen? What makes our lower jaw swing on the wrong path of closure, why does it develop in the wrong position, and why do our teeth come together incorrectly? Before going any further, let’s talk about the underlying causes of TMD.