When a patient has a Class II discrepancy, the upper and lower jaw bones do not line up. The upper jaw bone, supporting your upper teeth, is farther forward that your lower jaw. Because of this bone foundation discrepancy, the teeth will not line up properly. This foundation miss-alignment causes bite problems. Bite problems, due to improper jaw function, over time, can cause jaw pain, abnormal teeth wear and tooth loss.
The Causes Of Class II Foundation Discrepancy
During normal adolescent growth, the lower jaw has more growth and grows for a longer period of time than the upper jaw. As a child grows, the typical facial profile tends to become straighter by adulthood. This occurs because the lower jaw grows more that the upper jaw. Class II patients have less total lower jaw growth, thus creating jaw and teeth miss-alignment. The upper jaw structure is not supported by the lower jaw. Without treatment, the patient the problem can get worse.
Three Different Ways To Treat Class II Foundation Discrepancy
Headgear – wear an external appliance to create force on the upper jaw to modify jaw bone growth
a. Extractions remove one or more teeth in the upper jaw, creating room for the front teeth to move back into correct position.
b. In severe cases, bone and tissue from the jaws are moved and modified to correct the skeletal disharmony
3. TAD’s – (Temporary Anchorage Devices) see description and AAO link below
The Goal of Headgear Wear: Growth Modification
Using the force created by the headgear, the bone growth can be modified. The upper jaw teeth are held back or moved back to line up with the lower teeth and jaw.
How Does Headgear Work?
The headgear transmits force to the upper back teeth, which transmits force to the upper jaw. This force causes a change in bone growth, which over time corrects the jaw growth discrepancy found in Class II Foundation Discrepancy cases. In other word, “The headgear applies steady pressure to your upper jaw and over time, this pressure moves your upper jaw in line with your lower jaw.”
Headgear tubes are attached to the upper jaw, via the back the molar teeth, on both sides. Strong wires fit into each headgear tube and are then attached to straps worn outside on your head and neck. These strong wires, because they’re attached to external straps, create pressure on your upper jaw. This pressure modifies the upper jaw growth, to correct the Class II jaw mis-alignment.
Growth And Headgear Wear
During the growth phase, consistent headgear wear can effectively correct Class II Foundation Discrepancy. With proper patient compliance, extractions or surgery can be avoided.
If a patient has finished most of their adolescent growth or headgear wear has been inconsistent during that growth period, three other options exist.
The three remaining options, to correct the Class II Foundation Discrepancy:
Temporary Anchorage Device (TADs)
Surgery (in certain cases)
The Extraction Option
To help give the upper teeth and jaw enough room to align with the lower jaw, teeth can be removed. Then the remaining teeth are moved back to close the extraction spaces. This allows the upper and lower teeth and jaws to line up properly.
The TADs Option
See AAO’s TADs instructional video link for more information: https://www.aaoinfo.org/media/videos/temporary-anchorage-devices
TAD's are placed in the mouth by an oral surgeon to create full time pressure on the molars. They create the same pressure that the headgear creates, only the pressure continues 24 hours a day. This continuous pressure takes full advantage of any remaining growth.
Depending on remaining growth, one or more of the options may be needed, to achieve optimal treatment results.