Prognathism (Underbite, Undershot Jaw)
What is Prognathism?
A common condition in certain breeds where the lower jaw (mandible) is significantly longer than the upper jaw (maxilla) leading to a variety of Underbite, Undershot Jaw, Prognathism.
How does my dog get Prognathism?
In many breeds this is a normal breed characteristic, primarily the brachycephalic breeds. In other breeds where this condition develops it is an inherited defect of the development of the bones of the mandible. There are a very large number of breeds where this condition has been reported. A partial list is below.
How do I know if my dog has Prognathism?
To identify this condition simply observe the relationship of the two jaws. In a normal bite, the lower canines actually fit perfectly between the upper canine and the last incisor. In prognathism, the lower canine is deviated forward closer to the incisors increasing the gap between the canines. The lower incisors will also move in front of the lower incisors. Your veterinarian will confirm this diagnosis with you and determine the significance and the need for treatment if any.
What can I do about Prognathism?
Treatment for an underbite is reserved for those cases where the malocclusion is so severe that it is affecting the dogs ability to eat or chew or close its mouth. As a normal finding in many breeds, there is rarely any treatment needed. A combination of orthodontic manipulations and tooth removal may be needed in severe cases to allow for a somewhat normal chewing motion.
Is there anything I can do to prevent getting Prognathism?
As an inherited condition, there is little that can be done except for careful breed selection.
Are there certain breeds that get Prognathism?
Affenpinscher, Boston Terrier, Boxer, Brussels Griffon, Chinese Pug, English Bulldog, French Bulldog, Lhasa Apso, Shih Tzu.