Reasons for an Undershot Jaw in a Bulldog

Brachycephalic breeds of dogs, such as bulldogs, have underbites or undershot jaws. This means the lower jaw sticks out beyond the upper jaw. An undershot bite is an anterior cross bite where the lower incisors extend further to the front than the upper incisors but all of the other teeth come together properly. An undershot is a desired trait in a bulldog. However, if an undershot jaw appears in a breed that isn't built to accommodate the undershot, the condition may require corrective surgery.

  1. The Bite

    • A level or even bite occurs when the upper and lower incisor teeth meet edge to edge. When there is constant contact between the lower and upper incisors, this can result in periodontal disease, tooth loss and uneven wear.

      Bulldogs are short-muzzled breeds and underbites are expected, but an underbite or undershot that occurs in medium-muzzled breeds is not desired and it is considered abnormal, notes Dentalvet.com.

    Head Shape

    • Dogs like the bulldog have wide and short muzzles. The muzzle includes the nose and the mouth or the projecting part of the animals' face. That is one basic dog head shape. A second head shape is long with a narrow muzzle. This head shape is found on dobermans and greyhounds. The third shape is medium length with a medium-width muzzle, such as with terriers, most spaniels, labs, German shepherds and hounds. Vets have to consider the head shape of the dog when determining if the dog's bite is normal.

    The Opposite Condition

    • The opposite of the undershot jaw is the overshot jaw in whihc the upper jaw extends beyond the lower jaw. This condition, called prognathism, makes the upper teeth overlap the lower teeth without touching.

    History

    • The original bulldogs came from England. where they were working dogs. American bulldogs were bred after World War II by John D. Johnson and Alan Scott. The J. Johnson dogs were called "bully" and are heavier in bone, with larger heads and bulkier bodies, more pronounced undershot bites and a shorter muzzles than their predecessors. Scott's dogs are considered "standard" and they have longer muzzles, less bone than the bully dogs and less of an undershot.