Disorders of the Facial Skeleton Structure and Growth

By Dr. Vishaal Bhat on Thursday 6 December 2007 with 0 comments



Some of the dental arches mutual position anomalies are determined by deviations in size, position and bearing of the jawbones. These anomalies are often hereditary, although they may be caused by external factors as well.


Prognathia maxillaris is characterized by an excessive growth of the upper jaw in forward direction, while the lower jaw has normal shape and size. The upper frontal teeth do not touch their lower antagonists and protrude out of the mouth, in majority of cases. Chewing of food is difficult, sometimes impossible. The shortened upper lip does not overlap the upper frontal teeth, the lower lip gets inserted between rows of teeth.


Progenia mandibularis is characterized by a large lower jaw, while the upper jaw’s size is at normal range. It is one of the most prominent jaw anomalies and appears at the rate of more than 1% in our population. Hereditary factors play a role at its etiology; although acquired progeniae occur as well, for instance during endocrine glands malfunctions (acromegaly). Increased occlusion and enlarged lower jaw’s body, resulting in the horizontal overlap, are typical for a progenia. Mastication functions of the teeth and speech ability are usually hampered. An altered configuration of the face - enlarged lower third and emphasized chin - does not look nice. That is why this anomaly is often corrected by a surgery after the growth of jaws is completed.


Pseudoprogenia is characterized by a small upper jaw, while the lower jaw’s size is at normal range. This anomaly can be most frequently seen in cases of clefts, that are results of a combination of hereditary causes (insufficient development of the premaxilla) and external factors (consequences of operation scars). It is accompanied by the inverted bite.


Microgenia originates as a result of small lower jaw and is accompanied by distocclusion. The chin projection is absent and the chin changes over to the neck’s upper part almost imperceptibly. The nose and the upper lip, that overlaps the lower lip, protrude from face profile. This disorder may be of hereditary origin, more often it appears after an injury or inflammation of the jaw joint during childhood.


Laterogenia is caused by an increase or reduction in size of one half of the lower jaw, less often by skewing the whole jaw from its normal position. It occurs with the face asymmetry.

Category: Orthodontics Notes

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