Some jaw malformations may be present at birth or they may appear as the child grows. They can cause chewing and eating problems, abnormal speech and eventually lead to the early loss of the child’s teeth. When the upper and lower teeth do not meet properly, this condition is called malocclusion. Very often, an orthodontist is consulted, and if the child’s poor bite alignment is primarily due to dental issues, the orthodontist may recommend therapy to correct it.
For reasons that are not well understood, a child’s upper or lower jaw may not grow and develop proportionately.
Bone Repositioning with Orthognathic Surgery
If the misalignment goes beyond dental issues and is related to a skeletal problem, surgery may be needed–often along with orthodontic treatment. This surgery, called orthognathic surgery, creates a cut or osteotomy in the affected jaw, and the bones are repositioned so that they align better. Generally, the bones are held in their new positions with plates, screws and wires. The child may also need arch bars, a type of temporary braces, placed on the teeth to hold the jaws together and add stability (a procedure called fixation). This procedure realigns the upper and lower jaws so that, when they are brought together, the child's bite is aligned.
Jaw surgery is also used when the jaw is out of proportion to the rest of the face such as may occur in the following conditions:
- Cleft lip and palate
- Treacher Collins syndrome
- Hemifacial microsomia
- Pierre Robin sequence
Bone Repositioning with Distraction Osteogenesis
Another kind of surgery that can be done to correct jaw deformities is bone positioning by distraction (separating). This surgery was originally developed for lengthening uneven limbs, but it has now been adapted to meet the needs of children with congenital or acquired skull and jaw deformities.
This method involves surgically dividing the bone that needs lengthening and reshaping it by gradually moving the bony segments apart with special hardware; the small distance between the bone pieces causes the body to generate new bone to fill the gap (osteogenesis). The bone pieces are kept in place during the first week following the surgical bone division, but during the next several weeks, the fragments are gradually separated at a rate of one to two millimeters per day. When the surgeon is satisfied that the best length and shape of the jaw has been reached, the hardware is left in place for an additional six weeks to support the area during final healing.
The primary advantage in this type of surgery is that it allows major reshaping of the facial bones without bone grafts or jaw wiring. Some plastic surgeons believe that distraction osteogenesis may be safer than other methods of reconstruction, since it may involve less blood loss. However, the distraction method does have risks: If the bone ends are moved apart too slowly, the tissue created in early bone healing (callus) may prevent further separation. If the bone ends are moved apart too rapidly, the callus may not mature into solid bone. Consequently, it is very important that the rate of bone separation allow for the best quality and quantity of bone formation.