How do functional orthodontics address an overjet (and overbite) caused by a protruded upper jaw?

Good question: I dont have enough space to cover it all, and i seem to a bit of "contrarian" here, but: functional means orthopedics, and in this case means positioning lower jaw forward. Science tells me it does not grow the lower jaw, it pulls it out of the socket and when biting puts a restraining effect on the upper jaw "headgear effect". There are many ways to manage overjet and overbite, and can talk more.

Functional appliance: Using functional appliances in orthodontic treatment depends on the age of the patient .At early stages like mixed dentition they play a great role of promoting bone growth and could easily treat that situation an example of that is bionator , twin blocks and frankel or inman and other appliances .With adults it depends on the amount of the over jet and over bite or the amount of max protrusion.

Growth is key: Orthopedic appliances are used in conjunction with the growing child to redirect the growth to a more favorable pattern. Basically, the jaws being the foundation of the teeth, othopedic appliances work on the foundations. With a good foundation, we have a chance to align the teeth with out extraction and detrimental facial changes. Common orthopedic appliances: herbst, headgear, expanders, .....

Same as rubber bands: This has been studied extensively by dr. Lysle johnston chairman at u of mich. The changes that occur are due to movement of the upper teeth the same as a headgear. The additional changes in the lower jaw do not exceed 1mm. Compared to a headgear. Headgear compliance (worn at night) is much greater and results are more consistent.

Movement: Can create space through extraction or slenderizing teeth and pull teeth in to reduce overjet.

Changing eruption : Functional orthodontics changes overjet and overbite in many ways. By altering the way teeth go together forces are placed on both the upper and lower jaw. In addition the eruption of the teeth is altered , as well as positions of teeth and spaces. The sum total of all of these effects change the overbite and overjet, sometimes very dramatically. Nothing ventured nothing gained.

In small ways: Functional appliances have limited effects. Research has indicated that it restrains the growth of the upper jaw, much like the effect of a headgear, and can manipulate the dentoalveolar bone (bone that houses the teeth) to a degree. A wire connected to the appliance can further retract upper teeth, reducing overjet. It does not effect basal bone(foundational bone), as does not grow lower jaws.

Not effective: The concept of Functional Jaw Orthopedics is to utilize muscle function to reorient skeletal units by affecting growth. It is modestly successful in growing children, and completely unsuccessful in non-growing adults. If a Dentist tries to sell you on Functional Therapy to treat skeletal imbalance in an adult, run (don't walk) to the nearest exit. See a fully qualified Orthodontic Specialist.

Functional Appliance: Technically, a functional appliance forces the lower jaw forward, which in turn places and orthopedic force on the upper jaw backward. This orthopedic force slows or halts the normal growth of the upper jaw. This can also be accomplished with 'head gear" or "neck gear". If the upper jaw protrusion is extremely pronounced, sometimes extractions of upper premolars can help. Ask the orthodontist.

Diagnosis > options: Protruded upper jaws are unusual, although they exist. More often the lower jaw is back, making the upper jaw seem protruded. For protrusion, upper teeth (jaw) can be moved back with quite a few appliances; pendex, cd distalizer, headgear, etc. Most often however, it is usually the lower jaw that needs to come forward. A herbst, mara, etc. Can work. If the mandible is too small > surg/distraction.

Many appliances: Many overbites (overjets to orthodontists) are dealt with by a wide variety of functional appliances. I know of no literature that stands the scientific test that shows that they"grow" the lower jaw, they all use the muscle tension of a protruded lower jaw to restrain growth of the upper jaw, as well as lean the lower front teeth outward. Genetics defines the size of the lower jaw.

Age dependent result: Functional orthodontic appliances redirect facial growth parameters to more a favorable result. They depend upon growth, best applied before age 11 in most children. We usually diagnose a retrusive lower jaw as opposed to a protrusive upper jaw, especially in caucasions. Headgear is the traditional appliance that most people will recognize. A herbst appliance is a great option.

Probably none: If the upper is protruded there is a skeletal jaw mismatch. Therefor , all the upper front teeth need backward movement. This is usually accomplished with extraction of teeth in the upper jaw and possibly in the lower as well, with full orthodontic therapy..

Misnomer: Most "functional" devices are hardly functional and they do not "grow" lower jaws despite wishful thinking. The effects are primarily mid-face and the interruption of dentoalveolar compensation is the most prominent part of the correction - no matter the device used or jaw addressed. The term "functional" is fading as the actual mechanisms are understood and removable devices lost popularity.

For you?: Functional orthodontics is most effective on growing children.

Unusual: Most of the time it's lower jaw too far back, rather than upper jaw too far forward. If upper jaw is determined by skull x-ray and measurements to be too far forward, for an adult braces + jaw surgery may be required. Functional appliances are only modestly effective for growing children and are totally ineffective for non-growing adults. See an orthodontic specialist for evaluation and rx.