| |
The
lower jaw, or mandible, is subject to many abnormalities as well. Mandibular
excess (protrusion) and mandibular deficiency (retrusion) are very common
in the general population. In patients with mandibular deficiency, a history
of snoring and possibly sleep apnea may also be present. Patients with
nighttime wakefulness, restless sleep, noisy breathing, and daytime somnolence
with poor school or job performance may have associated sleep apnea. Mandibular
deficiency is corrected after orthodontic treatment by moving the lower
jaw forward. Occasionally the chin may also need to be repositioned. Mandibular
excess, if severe, is corrected by moving the lower jaw back. In more
mild cases of mandibular excess, the problem is corrected by moving the
upper jaw forward. It is extremely important to determine whether preexisting
disorders of the temporomandibular joint mechanism exist. Together with
the orthodontist, other dental specialists, and the plastic surgeon specializing
in maxillofacial or craniofacial surgery, a treatment plan can be outlined
with special attention paid to the temporomandibular joint. Temporomandibular
joint ankylosis, or fusion, may limit the opening of the jaw. This may
result from trauma or congenital conditions, or be acquired secondary
to tumors and etiologies. Ankylosis can be treated by a variety of techniques
ranging from simple release of the fused joint to more extensive reconstruction
using the patients' own rib with a cartilage cap (costochondral graft). |