Various calculations and assessments of the information in a cephalometric radiograph allow the clinician to objectively determine dental and skeletal relationships and determine a treatment plan.Prognathism should not be confused with micrognathism, although combinations of both are found. It affects the middle third of the face, causing it to jut out, thereby increasing the facial area, similar to the phenotype of archaic hominids and other apes. Mandibular prognathism is a protrusion of the mandible, affecting the lower third of the face. Alveolar prognathism is a protrusion of that portion of the maxilla where the teeth are located, in the dental lining of the upper jaw.Prognathism can also be used to describe ways that the maxillary and mandibular dental arches relate to one another, including malocclusion (where the upper and lower teeth do not align). When there is maxillary or alveolar prognathism which causes an alignment of the maxillary incisors significantly anterior to the lower teeth, the condition is called an overjet. When the reverse is the case, and the lower jaw extends forward beyond the upper, the condition is referred to as retrognathia (reverse overjet). Classification
Alveolar prognathism
Not all alveolar prognathism is anomalous, and significant differences can be observed among different ethnicities.Harmful habits such as thumb sucking or tongue thrusting can result in or exaggerate an alveolar prognathism, causing teeth to misalign. Functional appliances can be used in growing children to help modify bad habits and neuro-muscular function, with the aim of correcting this condition.Alveolar prognathism can also easily be corrected with fixed orthodontic therapy.
Familial cutaneous collagenoma is an autosomal dominant genetic disorder characterized by the presence of multiple symmetric nodules on the trunk and upper arms in multiple members of the same family. The nodules are flesh-colored, asymptomatic, and they start appearing during adolescent years.It has been described in 10 families worldwide.These nodules are caused by an overgrowth of collagen fibers with an accompanying decreased number of elastic fibers.In some cases, this condition is associated with anomalies in other parts of the body. Genetics
In a 2-generation Israeli Jewish family (whose affected members were two biological cousins), Hershkovitz et al. found a heterozygous mutation in the LEMD3 gene in both cousins and in the unaffected father of one of them. Possibly related complications
In 1968, Henderson et al. described 3 American brothers with the condition, and found that each one of them had health complications: the first brother suffered from idiopathic cardiomyopathy, the second suffered from iris atrophy of the left eye with accompanying severe high-frequency deafness, and the third suffered from recurrent vasculitis. == References ==