Basic Bite Details TMJ/TMD
I enjoy serving my patients and giving them information that can improve their understanding of dental health. Your bite, or occlusion, is simply the position of your jaw when your teeth are together. Seems like a fairly basic idea, but your occlusion is very important and can affect your health in many ways. Until recently, most dentistry has been based on the assumption that wherever your bite was naturally the correct position. Today, most dental treatments are still planned from the patient’s existing or habitual occlusion. Because the habitual jaw position may be a reasonably good position, and because our body system is often adaptable to less than ideal circumstances, many of these procedures have acceptable results. However, there are also many times that treatment procedures carried out with “textbook” accuracy do not produce a result that is fully functional and comfortable. The growing field of neuromuscular dentistry goes beyond using your habitual bite as the basis for planning treatment. Neuromuscular dentistry considers the entire system that controls the positioning and function of teeth, muscles and joints. As a neuromuscular dentist, I seek to establish a harmonious relationship among these three main factors.
Understanding of your occlusion is important. As a neuromuscular dentist, I go about determining your optimal jaw position (finding your proper occlusion). In addition, you’ll learn the importance of your bite in most every major dental procedure and treatment, and explain how occlusion can be involved in pain and or dysfunction of various areas of the body.
Usually, we don’t think about moving our jaw or about how it’s done -we just do it. When most people think of their bite, they think of their teeth. But, as I mentioned earlier, there is a
whole system that controls the positioning of the jaw. Here are a few basics:
Different muscles come into play for posturing the jaw, opening and closing the jaw (biting or chewing), and swallowing. The muscles that open your jaw are in your neck. ‘The muscles that
posture” your jaw, or keep it from falling open, are rather delicate muscles that extend from the jaw upward through the cheeks and into the forehead area even around behind the ear to some extent. The power muscles for chewing are in the cheek area. Swallowing muscles (like all muscles)
must have something firm to brace against to function. Because the body is efficient, the posturing muscles generally hold the jaw at a position where the teeth are close to occlusion – a millimeter
or two apart. This is an efficient location since we must bring our teeth together to swallow hundreds of times a day. Control of all of this is done subconsciously without having to think about it – your brain is “programmed to do this through a process that doctors call proprioception. If everything is just right and the jaw is not moving, most of these muscles are said to be at rest, or barely working to maintain posturing. If your natural teeth don’t fit together properly, your muscles may accommodate, forcing the jaw to close on a path that stresses and fatigues the muscles over time. This puts the jaw in a ‘ position where the teeth are close to occlusion, but at the same time prevents the muscles from being relaxed when they should be.
The jaw is able to move since it operates on a joint called the temporomandibular joint, its name the basis for the often heard term “TMJ”. For descriptive purposes, you can think of a joint being something like a ball and socket, the jawbone portion (ball) of the joint functions within a depression in the skull (socket). There is also a soft pad called a disc that lies between these two structures. The position of the jaw end of the joint (the condyle) within the corresponding depression in the skull (the fossa) is largely determined by where the muscles are holding the jaw – a position in turn affected by the bite (occlusion). If the system is in balance, the condyles will essentially be centered in the fossa and the disc moves freely with the joint. If the muscles of mastication are accommodating as described above, they may be holding the jaw joint in an abnormal position, negatively affecting its function. Frequently this results in the disc being pinched, causing it to resist the movement of the joint until it finally releases. As the “pinched” disc releases, it results in the joint popping or clicking. This sound is , often obvious to you and is a sign of abnormal joint function that may in turn be related to your bite.
Posture can also play a significant role in your occlusion. The jaw could be considered one end of your interrelated skeleton, with the feet being the other end. If any part of the skeletal system is affected, it may in turn affect other parts of the system. You can experience this by lightly touching your teeth together, taking care to note which teeth first touch. Then, tilt your head back as far as you comfortably can and repeat the process. Don’t be surprised if the teeth first touch in a different location now. You have altered the balance of the skeleton (and your bite) by simply changing your head posture. Another example is if you have a filling placed when you are in a prone position in the dental chair. Under anesthesia, it feels as if the filling fits fine. Then later when the anesthesia wears off and you are sitting or standing upright, you notice that the filling is uncomfortably too high. It is for this reason that the neuromuscular dentist establishes your occlusion when you are seated in the upright position – the position in which you normally use your jaw. If it is established when you are in a reclined position, the jaw may have moved back, resulting in a position different than that in which you normally function. With head posture affecting occlusion, and because of the inter-relationship of the entire musculoskeletal system, the neuromuscular dentist will want to know if there is tension in the muscles of the neck and upper back. If there is, it may well affect the occlusion and therefore the outcome of the diagnosis or treatment. Now we are beginning to see that the bite is far more complicated than just the way the teeth fit together!
As you have now learned, neuromuscular dentists evaluate the muscles and joints in addition to the teeth to establish an occlusion that they believe is crucial to achieving optimal results in virtually every type of major dental procedure and in treating many types of pain and dysfunction. No matter what type of treatment you are considering, it is important that you understand the significance of getting your bite right.
Your Bite and Pain
In addition to achieving optimal long term results in your dental treatment, an imperfect bite can affect you in ways that you would normally think were non-dental related. The American Council for Headache Education states that “tension-type headaches are the common headaches of everyday life” and that they are often associated with muscle tension. Many of these headaches are temporal headaches – focused in the temple area of the head. And we just learned that the posturing muscles of the jaw are in the temple area of the head! These postural muscles should be relaxed and barely working when you are not eating, speaking or otherwise using your jaw. However, if they need to work overtime to posture the jaw because the teeth don’t naturally fit together right, they can go into spasm (constant tension) and produce pain in the forehead area. Some temporal headaches may result from other sources, but neuromuscular dentists have learned that a high percentage of them are a result of an improper bite or subconscious bite habits. Pain or dysfunction of the head and neck is a very common condition and one that might be resolved very simply or might be very complex and frustrating to treat, depending upon the circumstances. Because the true cause is sometimes very difficult to diagnose, such conditions have customarily been given a variety of non-specific names. These include such terms as TMJ (Temporomandibular Joint), MPD (Myofascial Pain Dysfunction), TMD Temporomandibular Disorder) and CMD (Craniomandibular Dysfunction). They are perhaps most often referred to in dentistry as “TMD” or the catch all term “TM J” . We have already discussed how bite problems can cause headaches. The bite also can be a factor in many other types of pain or functional problems because of the inter-relationship of the overall musculoskeletal system. Some of these problems can include painful clicking or popping of the jaw joint, various types of head and neck pain, swallowing problems, postural problems, and excessive snoring or sleep apnea. When you first see your neuromuscular dentist you may be asked about your symptoms.
In addition the dentist will be looking for a number of signs in your posture, appearance and condition of your teeth, and existing bite that might aid in diagnosis of TMD. An imperfect bite often plays a significant role in these conditions and the dentist experienced in treating them may be able to resolve the problem alone. However, diagnosing these problems can be very difficult at times and! may require the collective efforts of your dentist and other health care professionals, which may include your physician, an ear, nose and throat specialist, physical therapist, chiropractor, or massage therapist, to name just a few. The neuromuscular dentist also recognizes that at times there can be a non-physical, or emotional, aspect of pain dysfunction problems. Stress in your personal life or career, or subconscious habits can be a factor. When this is considered a possibility, or if physical treatment is not producing the expected results, your dentist may refer you to another health care professional for evaluation of possible emotional or biochemical aspects of your problem. Another type of pain/dysfunction condition is known as the pain-spasm cycle. It is a self-perpetuating condition wherein pain causes muscle tissue to stay in spasm which in turn causes pain
– a vicious circle. Sometimes if either the pain or the spasm can be interrupted, the condition subsides or disappears. The pain or the spasm may be alleviated through the use of drugs or electrical muscle stimulation. While interrupting the pain cycle may provide temporary relief, in these cases it is not uncommon for the condition to re-appear, either sooner or later. Simply interrupting the cycle does not get to the basic cause of the problem – it is a bit like taking aspirin for a headache without knowing what caused the headache.