Description, Causes and Risk Factors:
Mandibular prognathism is a common clinical problem all over the world. However, its prevalence varies relative to populations: the highest incidence has been observed in Asian populations (approximately 15%) and the lowest in Caucasian populations (1%). The unique concave profile of mandibular prognathism not only seriously affects the masticatory function but also extremely endangers psychology to patients. Today, this type of disharmony remains difficult for dentists because of varied etiologies and limited understanding of the mandibular growth.
It is well known that environmental and genetic components have both contributed to the etiology of mandibular prognathism. Various environmental etiologies, e.g. imbalances in the endocrine system and hormones, enlarged tonsils have been reported to be involved in the forming of mandibular prognathism. However, there is great interest in the genetic component of the etiology and numerous studies suggest that genetic components play an important role in its etiology. But the inheritance pattern of mandibular prognathism is heterogeneous, findings have been reported suggesting autosomal-recessive inheritance, autosomal-dominant inheritance, dominant inheritance with incomplete penetrance or a polygenic model of transmission.
Recent progress in molecular genetics has enabled the genetic determinant to be approached directly. Genetic linkage maps using various types of polymorphic markers are essential tools in many genetic studies. Short tandem repeat (STR) become popular genetic markers because of their polymorphism and hereditary. Yamaguchi and Frazier-Bowers performed genome-wide linkage analysis with STR respectively and found out some mandibular prognathism susceptibility loci - 1p36, 6q25, 19p13.2 and 1p22.1, 3q26.2, 11q22, and 12q23.
Recently Cruz RM examined data on 55 extended families with at least one affected member with mandibular prognathism and performed a complex segregation analysis to access the inheritance pattern. It turned out that the majority of the pedigrees suggested autosomal dominant inheritance.
Anxiety and concerns about jaw alignment.
There is difficulty talking, biting, or chewing related to the abnormal jaw alignment.
Diagnostic tests may include:
Imprints of the bite (a plaster mold is made of the teeth).
Orthognathic surgery in conjunction with orthodontic treatment is required for the correction of adult mandibular prognathism. The two most commonly applied surgical procedures to correct mandibular prognathism are sagittal split ramus osteotomy (SSRO) and intraoral vertical ramus osteotomy (IVRO). Both procedures are suitable for patients in whom a desirable occlusal relationship can be obtained with a setback of the mandible, and each has its own advantages and disadvantages. In bilateral SSRO, the intentional ostectomy of the posterior part of the distal segment can offer long-term positioned stability. This may be attributable to reduction of tension in the pterygomasseteric sling that applies force in the posterior mandible.
NOTE: The above information is educational purpose. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition.
DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.
According to recent research, published in the journal Immunity, probiotics can be used safely and efficiently to fight osteoporosis, widely-known as osteoporosis. The researchers have used a mouse model to check the hypothesis. The mice received oral Lactobacillus...
A new study, published in the Journal of Applied Psychology, finds that a hot bath may help reduce inflammation and improve metabolism. As a part of an experiment, each study participant took a hot bath with water temperature 102°F (39°C) for one hour. The researchers...
Factors such as age, gender, physical activity, genetics, medical history, body type, and others directly affect not only the desire to lose weight, but also to follow the right diet. Everything is relative, everything is individual. Nevertheless, there are universal...read more
It is very entertaining to be a sport fan. There is a big variety of sport games that are extremely interesting to follow. Moreover, it is always fun to anticipate the score and watch the enthusiasm live. One of the benefits of being sports fan is using different...read more
A new study of nearly 18,000 participants found that those with high fitness at middle age were significantly less likely to die from heart disease in later life, even if they were diagnosed with depression. Doctor's Tips: How to Stay Fit While Treating Depression Dr....read more