Dr A Mistry's Clinic - Orthognathic Surgery

Orthognathic Surgery

Prognathism, from the Greek pro, "forward" and gnathos, "jaw", is a dentofacial deformity of varied causes, (although with a large genetic component). This malformation is described by the presence of an anteroposterior discrepancy between the jaw and the upper jaw, that is, both bone structures are misaligned with each other.
In cases of mandibular prognathism, the jaw is developed by excess in relation to the maxilla and the inferior dental arch extends forward beyond the superior, causing a Class III malocclusion, also known as underbite.
Class III skeletal malocclusion with a prognatic jaw is one of the most serious maxillofacial deformities, although it is important to underline that this is considered a disorder only if it affects mastication, speech or social function due to a great aesthetic imbalance.

CAUSES OF PROGNATISM

Prognathism is considered a malformation of eminently genetic causes, although its etiology is still multifactorial. Thus, a combination of inheritance and environment can enhance or decrease malocclusion.
Among the environmental factors involved, we can mention oral habits, hypertrophy of tonsils or adenoids, premature loss of temporary teeth, endocrine alterations, etc.
According to these factors, the malformation manifests itself in different ways:

When the jaw bone shows abnormal excess growth (mandibular hyperplasia) with respect to the maxilla, known as skeletal class III.
When the prominent jaw is due to a dental problem, that is, when the teeth are misaligned with each other.
When the patient has an excess of the chin, he may have a prognata appearance, although strictly speaking it is not a Class III.

TREATMENT OF MANDIBULAR PROGNATISM

The modification of facial growth by dentofacial orthopedics can be an effective method to resolve skeletal discrepancies of the Class III jaw in growing children. If prognathism is diagnosed in adulthood, and depending on where it occurs, there are different treatment options:

For a class III that is only dental, the indicated treatment is orthodontics, although it is important to mention that a functional cross-bite preserved over time can become skeletal, hence the importance of early treatment.
For an overdeveloped chin (an apparent prognathism, but no class II maloclussion), the treatment consists of a mentoplasty or chin reduction surgery
For a class III skeletal malocclusion, orthognathic surgery is necessary:
• Bimaxillary surgery, when the maxillofacial surgeon needs to intervene surgically on the mandibular and maxillary bone
• Monomaxilar surgery, when the maxillofacial surgeon only acts on one of the two skeletal structures.

WHY TREAT MANDIBULAR PROGNATISM OR CLASS III

The common characteristic that defines both a prominent lower jaw, and a retracted upper jaw, is that in both cases the patient has a Class III dental malocclusion, that is, the lower teeth are in front of the upper teeth, a condition that transmits certain hardness and aggressiveness to the facial features of patients with this type of problem.
The solution of the mandibular or class III prognathism solves functional problems, such as discomfort when chewing, pain in the temporomandibular joint (TMJ), and even improves the patient's diction (which in many cases presents with lisp). In addition, after the intervention, a great aesthetic improvement is also achieved: the facial features become softer, finer and more harmonious, eliminating the psychological obstacles of having a facial deformity.