The three major components of the stomatognathic system are the teeth, the bone, and the musculature. A balanced stomatognathic system exists when there is normal expression of a person's hereditary pattern, without the influence of unfavorable internal or external forces.
Abnormal forces close malocclusion. Most patients' malocclusions entail more than just the malposition of teeth alone. Often there are orthopedic discrepencies and muscular dysfunctions as well in treating these patients, equal importance must be placed to cornering both the dental and skeletal abnormalities.
Functional appliances are used to control and direct orthopedic and muscular forces in an effort to prevent or correct a malocclusion. They are designed to influence the growth and development of the facial skeleton in a vertical plane, a horizontal plane or both.
Functional appliances are designed too work hand-in-hand with nature. The uniqueness of functional appliances is their mode of force application. They do not act on teeth like conventional appliances, using springs and elastics, but rather transmit, eliminate or guide forces. Some of the, natural forces that can be controlled by functional appliamccs are: muscle activity from the tongue, lips, and check; tooth eruption; and growth direction of the maxilla and mandible.
Although functional appliances also exert an orthodontic effect on the dentoalveolar structures, improperly shaped, shortened, narrowed or crowded arches, should first be prepared by one of the arch preparing appliances described in the arch development chapter of this book.
Functional therapy is usually used, when teating children, to give the patient's normal hereditary pattern a chance to express itself. Therapy- must start early so it will have the greatest opportunity to use growth in its favor. For example, the best time to accomplish Class II corrections is between 9 and 11. At this age, the patient is usually mature enough to follow your instructions while there is still plenty of time left for growth. Also at this age, with the use of an appropriate cephalometric analysis, you should have a more accurate picture of the patient's growth pattern.
Diagnosis is the key to successful functional Orthopedic care, as an abnormal jaw-to-jaw relationship can be due to multiple factors. For example, a Skeletal Class II relationship can occur because the maxilla is too protrusive, the mandible is too retrusive or both may be contributing in varying degrees simultaneously. What is needed from a cephalometric analysis is, not only whether or not the case is in fact a Class II, but also which member of the jaw-to-jaw complex is errant and to what extent. This knowledge is the key to choosing an appliance and technique to correct the problem.
Functional therapy may also be used when treating adult patients. Although the sequence of treatment and the types of appliances used may be different when treating an adult, the basic concepts remain the same:
• Always respect the health of the Temporomandibular Joint. This can best be accomplished by creating a harmonious balance between the muscles, bones, and teeth.
• Treatment direction will totally depend upon the diagnosis of the patient's existing skeletal, dental and muscular relationship. All three components must be addressed to achieve a stable result.