There is likely no topic in dentistry more poorly understood than that of the relationship of dental biomechanics to dental health and the comfort and longevity of our dental restorations and implants. There is also not one that is more important. The purpose of this section is to explain what biomechanical factors and biomechanical harmony are, what they affect, how they have these effects, and why they are so important. To better understand these things, there are a few important terms we need to define.
To begin, what are biomechanical factors? The term “biomechanical factors” refers to those factors involving movement of the mandible (the lower jaw member and the only member that moves) and the forces that result on all parts of the jaw system (the teeth, periodontium, jaw joints, and jaw muscles) as a result of this movement. Because these factors involve so many structures, they affect virtually every aspect of dental care – including the treatment of head and facial pain, fixing worn or damaged teeth, improving smiles, replacing missing teeth with dental implants, and treating periodontal disease.
“TMD”, “TMJ Dysfunction”, or “TMJ Disease”:
More often than not, the terms “TMD”, “TMJ Dysfunction” or “TMJ Disease” are misused as a diagnosis or disease. When used properly, the term “TMJ” actually describes the jaw joint (the Temporomandibular Joint), just as the term “Knee” describes the knee joint – both of which are complex joints of the human body and not diseases or diagnoses. When the terms “TMD”, “TMJ Disease” or “TMJ Dysfunction” are misused to describe a patient’s condition, they are actually non-specific terms that describe a wide variety of problems ranging from head and facial pain, to damaged or clicking jaw joints, to worn or broken teeth. Three things these problems have in common is that they are all caused or affected by biomechanical factors, they involve structures of the jaw system, and they can be treated (See “Biomechanical Disharmony: Problems, Evaluation, and Treatment”). Why a more specific description of the problem is so important is because each type of problem has different treatments. A specific description is what is referred to as a “diagnosis”. However, regardless of the diagnosis, these problems virtually always involve biomechanical disharmony between the jaw muscles, the jaw joints, and the way in which the teeth come together during function (the “Occlusion” or “Bite”).
To better understand the nature and importance of the term “biomechanical disharmony”, and its affect on various parts of the jaw system, it is helpful to understand that the brain can activate the jaw muscles to close the mandible (along with the teeth) to many different positions. This is a process called “engram programming”. To illustrate this phenomenon, you may have had a filling or other dental restoration placed that felt a little “high” or “off” at first, but after a few days it felt normal again. It felt normal again not because the restoration changed but because the brain re-programmed the jaw muscles to close the mandible slightly differently to allow the teeth to come together more evenly again. Unfortunately, this seemingly helpful response also causes many problems. It does so because it results in mechanical forces (stresses) being placed on the jaw muscles, jaw joints, periodontium, and all the teeth (See “Biomechanical Disharmony: Problems, Evaluation, and Treatment”). It may also lead to harmful habits such as tooth clenching or grinding (bruxism).
This disharmony of the relationship between the teeth and jaw muscles may result from many causes – from oral habits, abnormal breathing or swallowing, missing or shifting teeth, dental treatment, or degenerating jaw joints (TMJ’s), to name just a few. It may also be very large (several millimeters) or very small (20 microns or less – about one third the thickness of a human hair). However, whatever causes the disharmony and regardless of its size, for many patients, it is the number one cause of tooth damage, failure of dental restorations and implants, dental pain, tooth loss, and even head and facial pain. It is also the number one cause of tension headaches.
Affects of Biomechanical Disharmony:
Biomechanical Disharmony and the Teeth
Affects of stresses from biomechanical disharmony on the teeth include excessively worn, broken, and sensitive teeth. In fact, stresses from bite problems or grinding result in so much tooth sensitivity that they are the number-one cause of unnecessary endodontic (Root Canal) treatment. This pain could have easily been eliminated by an adjustment of the bite or wearing an oral appliance. Biomechanical stresses are also the number one reason patients need extensive dental treatment to repair severely damaged teeth and smiles (see “Restoring Damaged and Unattractive Teeth”).
Biomechanical Disharmony and the Periodontium
Affects of stresses from biomechanical disharmony on the periodontium include receding gums, loss of boney root support, and loosening of teeth. These stresses also work together with microorganisms to speed up the advancement of periodontal disease. As with the affects of biomechanical disharmony on the teeth, those impacting the periodontium may ultimately lead to the loss of teeth. They can also be predictably improved with a proper bite adjustment or use of an oral appliance (see “Periodontal Disease, Tooth Loss, and Whole Body Health”).
Biomechanical Disharmony and the Jaw Muscles
Biomechanical disharmony problems involving the jaw muscles are among the most common causes of pain in humans. It is the jaw muscles that generate all biomechanical forces, and they may be either the cause or the victim of these problems. In either case, these problems always involve functional disharmony between the jaw muscles, jaw joints, and the teeth, as described above. Muscle over-activity resulting from this disharmony can cause damage or pain to the teeth, jaw joints, periodontium, or dental restorations. However, this over activity may also lead to injury of the jaw muscles themselves. When this occurs some type of facial or head pain will likely occur. Included in these are sore or aching jaws, shooting or radiating pains in the face or ears, and headaches. As described above, muscle injury from biomechanical disharmony associated with the bite is the number one cause of tension headaches.
Biomechanical Disharmony and the Jaw Joints (TMJ’s)
In addition to being one of the most complex joints of the human body, the TMJ is also one of the most important ones, as it is needed for us to take in nutrition to live.
As with the jaw muscles, problems associated with the TMJ’s may also be either the cause or result of biomechanical disharmony. Damage to the TMJ’s results in a wide range of conditions – from a simple painless “clicking” or “popping” sound, to severe facial pain, to complete destruction of the TMJ’s and facial disfigurement. These problems may happen as a result of stresses from biomechanical disharmony as described above, from external trauma (such as a blow to the jaw), from systemic health problems (such as Rheumatoid Arthritis), or from any combination of these.
Because the relationship between upper and lower teeth changes as the jaw joints break down, in addition to being the result of biomechanical disharmony, TMJ damage can also be the cause of this disharmony. In a “vicious cycle” response, this resultant bite change causes additional stress and potential damage to every part of the jaw system, including the jaw joint itself. Therefore, any problems affecting the teeth, dental restorations, periodontium, or jaw muscles associated with biomechanical factors may in fact be the result of TMJ damage.
Treating Biomechanical Disharmony
Treating biomechanical disharmony involves restoring harmony between the teeth, jaw joints, and jaw muscles when they are in function. Since the teeth are the most accessible and easily adjusted of these structures, a bite adjustment or “RedAddibration” is often the treatment of choice. However, regardless of the way it is treated, it should be understood that restoring biomechanical harmony is only one part (although a very important part) of restoring a patient’s overall dental health, comfort, and esthetics – just as is helping patients achieve a healthy periodontium. In the end, biomechanical disharmony is best treated in a way that considers all of a patient’s dental wants and needs (see “Biomechanical Disharmony: Problems, Evaluation and Treatment” and “Restoring Damaged and Unattractive Teeth”).
Why Biomechanical Factors are so Poorly Understood
If they are so important, why are dental biomechanical factors and the problems they cause so poorly understood by most patients and dentists? The answer lies in the complexity of the subject. Because these problems involve interactions between so many structures and cause so many types of problems, there is simply no easy way to understand everything that is involved with evaluating and treating them. Leaders in biomechanical issues have spent entire careers learning how to master evaluating and treating these problems. Dr. Hegyi has personally spent over thirty five years acquiring the training and experience to better understand dental biomechanics and to apply these principles to benefit all dental treatments – from treating facial and head pain, to smile makeovers, to repairing severely damaged teeth, to the rehabilitation of patients who have lost their teeth with dental implants. It has also become a passion of Dr. Hegyi to share this knowledge with his patients, other dentists, and the medical community.