Jaw deformities may occur as a result of different rates of growth of the upper jaw (maxilla), the lower jaw (mandible), or both. They may be present at birth, follow a traumatic accident, or develop with growth of a tumor. The care of patients with jaw deformities involves coordination between the patient's dentist, orthodontist, and plastic surgeon. The team at the Cleft and Craniofacial Surgery Center at Mount Sinai is highly experienced in treating jaw deformities of all kinds, especially complex cases.
Condition We Treat
At The Mount Sinai Hospital, we treat many conditions affecting the jaw, including:
- Mandibular hyperplasia (also known as "prognathism"): In patients with mandibular excess the lower third of the face appears very prominent. Historically, this was seen in the Hapsburg family of Spain. This may or may not be seen with underdevelopment of the upper jaw.
- Mandibular hypoplasia: The patient with a small lower jaw presents with overbite (skeletal malocclusion). There are many causes of mandibular deficiency, including Pierre-Robin sequence, agenesis of the condyle of the mandible, Treacher Collins syndrome, hemifacial microsomia, trauma in childhood, ankylosis secondary to trauma or infection, juvenile rheumatoid arthritis, and lastly the idiopathic type, which may be an inherited or unknown cause of a developmentally small lower jaw. Sometimes, patients with a tall upper jaw in the setting of long face syndrome have the appearance of a small lower jaw due to backwards rotation of the lower jaw.
- Maxillary hypoplasia: A person with small upper jaw will tend to have a shallow, concave midface and an underbite (skeletal malocclusion). The lower jaw may be undersized, oversized, or normal. It may or may not be associated with clefting of the lip and/or palate or a more complex craniofacial syndrome (e.g., Apert, Crouzon, Pfeiffer, Kleeblatt-Schaeddel, or Binder syndrome).
- Vertical maxillary deficiency (also known as "short face syndrome"): Vertical deficiency of the upper jaw may give the patient an older appearance due to the absence of enough dental show. With the ability to rigidly fixate the bone, modern results have been highly successful with little relapse.
- Vertical maxillary excess (also known as "long face syndrome"): In contrast to the vertically short upper jaw, patients with excess vertical height of the upper jaw present with the appearance of a long face. An open bite, in which the teeth do not come together, may or may not be a component of the long face syndrome. This is due to a disproportion of the vertical excess, more vertical growth occurring in the back of the maxilla versus the front and an associated shortness of the lower jaw.