It has been said that form and function are two halves of the developmental sphere that help guide normal growth. In a similar manner dysfunction and compensation are two halves of a dysfunctional growth and adaptation process.

The growth and adaptation of the upper quadrant is a relational process between the structural development of the component parts and the abilities of these components to function. When this process occurs in a relational manner there is minimal compromise in form or function.
The condyle should contact the central avascular portion of the disc which should function against the anterior slope of the eminence. There should be a consistent contact of these structures in all movements without any displacement or dislocation of the disk. The joint structure should be supported by normal muscle function with a Class I mutually protected occlusion.

tmj-quadrant-1This representation of the upper quadrant depicts an artist’s representation of a normal spatial relationship of the components. There is a balance in the anterior and posterior components and the structures are aligned in a fairly symmetrical horizontal and vertical manner. The functional components when viewed from an anterior / posterior manner would be relatively symmetrical with the right side being almost a true mirror image of the left side. The structures would thereby be able to function simultaneously with both right and left components being able to undergo the same functional movements without compromise.

tmj-quadrant-2If humans developed in a truly symmetrical manner we would all look like the photograph on the left. This is a super-imposition of the patient’s right side copied and flipped horizontally so the left and right components are mirror images of one another. This type of symmetry would enable the patient to function as ideally as possible with the right and left components being symmetrical and therefore being able to function in a similar or like manner. Opening, closing, speech, etc. would be as harmonious as possible and there would also be little cause for compensation or compromise if the structures were symmetrical.

tmj-quadrant-3We humans, however, are seldom symmetrical. We can begin to realize that most humans are not symmetrical, but are in fact a compromised being where true symmetry seldom exists. Said another way, we humans compensate for our dysfunctions in form and function. Most people are able to function without indications of major tissue injury, damage or breakdown if the compensations are limited and are within our capacity to compensate, which will vary from individual to individual. Fortunately the human structures are rather adaptive and thresholds of dysfunctional compensations are seldom exceeded, resulting in an awareness or pain.

One of the developmental aspects of the upper quadrant is the form and function of the mouth, joint, head and neck associations. One way to understand this concept is to understand what is normal and use this normative aspect as a comparison for dysfunction. The human temporomandibular joint (TMJ) apparatus is a complex interrelationship of multiple forms and functions. Our search for understanding begins with the normative development and normative function of the TMJ.

The angulation of the maxillary anterior teeth should coincide with the angulation of the slope of the eminence within a matter of a few degrees. As the mouth is closed into a fully occluded position, the condyles will fully seat against the relatively avascular central region of the disc against the anterior slope of the eminences. The forces applied to the teeth due to the dental angulations should coincide with the anatomy of the joint for these structures to function in a harmonious relationship.

The TMJ in these slides from left to right shows the joint fully closed meaning the teeth are together (1), then goes into opening (2), full opening (3) and closing movements (4). The muscles and joints determine the spatial relationships except for the top slide on the left, where the teeth determine the joint associations.

Therefore, under ideal circumstances the position of the joint as determined by the muscle, joint, and upper quadrant proprioception should be the same spatial relationship as determined by the patient’s fully occluded dental associations. When this harmonious relationship exists the joint is able to function in a painless and noiseless manner with a full range of motion.

The developing TMJ is highly innervated without a significant adult form during the first few years of growth and development and the deciduous dentition develop within the confines of the developing upper and lower jaw. The adult formation of the human joint begins around the age of 5 to 6 years of age, about the time that the permanent adult teeth begin to replace the deciduous or baby teeth. The human TMJ is composed of a fibrocartilagenous lining of the fossa/eminence and the anterior and superior aspect of the condyle and the disc is fibrocartilagenous in nature.

The forces of the condyle on the fibrocartilagenous disc appear to be the determining factor on the disc development. As observed in the above slide of a normal functioning human TMJ, the nose is to the left and the back of the head would be to the right. The posterior aspect of the disc is larger than the disc tissue between the condyle and eminence and is highly innervated and vascularized. The disc central region has been formed because the condyle exerts pressure against these structures. The posterior aspect of the disc is larger than the central region and it is this larger posterior region that is responsible for maintaining the disc position between the ball and socket of the joint.Viewed in this image, it is the posterior and superior movement of the condyle that has first distorted or flattened the posterior aspect of the disc. Loss of this mechanical property by the compression of the condyle allows the disc tissues to be displaced by further seating of the condyle in a posterior and superior manner as observed on the right. The position of the condyle determines the compensations that occur in the disc tissue, therefore, to maintain the integrity and function of the disc it would be necessary to control the position and forces of the condyle on the inter-joint structures.

tmj-quadrant-7Clicking occurs when the fibrocartilagenous disc is displaced from the proper functional position by the movement of the condyle (posterior and superior)and it slips into and out of position; resulting in the clicking or popping that patients are able to ascertain.Clicking is an indication of joint dysfunction. Clicking is an indiction that the structures are not functioning properly. Clicking is an indicator that something needs to be done to help control the forces causing the dysfunctional tissue compromises and dysfunctional movements.

Instead of opening straight to a normative measurement of 48 to 52 mm, the patient is noted to have a deviation in opening and/or a limitation in opening. Deviation in opening or a limitation in opening dimensions is an indication that the structures are not functioning in a normative manner and some form of examination, diagnosis and / or intervention is appropriate.

tmj-quadrant-9The muscles move the mandible and the TMJ. The muscle function is compromised if the internal joint components become dysfunctional. Muscle compromise can result in dysfunctional muscular regions called trigger points that can cause local and referred pain.

There are multiple aspects of how the joint becomes compromised from being displaced in a posterior and superior manner. One of the obvious aspects is the relationship of the patient’s dentition and how the fully occluded position affects the mandibular / maxillary relationship.

Compensations if form and function and the compromise leading to dysfunction can start at a very early age. This young man suffers from headaches of unknown origin, but the headaches are temporal and posterior cervical in origin.

Viewing the developing structures does little to uncover the cause / effect aspects that are leading to the patient dysfunctional development. Spatial analysis, examinations at this association would yield little to uncover why the patient is developing into a dysfunctional association.

Viewing the patient in a functional position begins to help determine how/why the mandible has a posterior and superior position, why the joint structures are being compromised and how/why the muscles may not be able to function in a normal manner. The habitual bite is not where the patient should grow and develop and interception is needed if a normal form and function are to result.

The functional position is first established and then the teeth are moved to support the best jaw, head and neck relationships. The teeth, joints and muscles are then able to function in the most harmonious relationships.

These photographs are just a few examples of the various methods that are components of the TMJ-Orthodontic method to move the teeth to support the best functional relationships determined at the start of treatment. Failure to establish the best functional relationship may allow treatments to result in associations that are not in harmony.

The braces have helped move the teeth to come together in the bite position that was found to be the best joint and muscle position.

What are the signs and symptoms that a patient has an upper quadrant dysfunction?

Headaches

Location, intensity, onset, duration, what makes them better and what makes them worse.

Neckaches

Upper, mid, lower neck, limitations and restrictions in movements

Earaches

Medical causes need to be ruled out, but the ear region is a common pain referral pattern.

TMJ

The TMJ should be painless, noiseless, posses a full range of motion and be free of deviations.

Facial Pain

Facial pain should have a discernible cause of pain, or be considered a possible referred pain.

Jaw Movement Mechanics

Painless: There should not be pain when palpating the joint during movements.
Noiseless: A healthy joint does not make noise during a full range of motion
Full Range of Motion: 48 to 52 mm in opening and 10 -12 mm in excursive movements
Straight opening: The mandible should open straight without deviation or deflection

Cervical Movements Mechanics

The structures of the neck, shoulders and upper back have to compensate for any dysfunction in TMJ or front region. This can cause muscle pain and compromise.