Short Jaw Sandra L. Waugh VMD, MS

Short Lower Jaw. Don’t Just Sit and Watch, Do Something

Sandra L. Waugh VMD, MS - Windsor Pet Dental

Every year I examine puppies whose jaws are not growing properly. I would really like these puppies to come when they are 8 weeks of age. Treatment for these abnormalities must be started as soon as possible. Too often owners are given the advise to “wait and see” rather than taking immediate action. Many puppies get their first vaccinations at 8 weeks of age and if the jaws are not matched in length action should be immediately be taken.

This is a dog who was not treated as a puppy. Dog jaws are very powerful and a large hole in the roof of the mouth can result from impact from a canine tooth.

This hole in the hard palate is what can result from a lower jaw canine digging into the hard palate over time. This is an adult dog. Treatment: The lower canines were shortened and immediately capped and the lower incisors were extracted.

How the teeth come together is called Occlusion. In the front of the mouth the normal occlusion is very tightly spaced. Unmatched jaw lengths result in a Malocclusion.

Let’s review how the jaw grows in a young dog. As the upper jaw grows forward the maxillary canines press on the mandibular canines and “push” the mandible along. As the mandible grows forward, the mandibular incisors press on the maxillary incisors and “push” the maxilla ahead. in this way the proper relationship between the jaws is maintained until the full growth has occurred. When the mouth is opened and closed, the teeth do not hit the opposing soft tissue and the dog is free of oral pain.

Normal bite in a dog.

Maxillary Canine

Maxillary Third Incisor Maxillary Incisors

These are adult teeth. The deciduous teeth should also have this pattern.

Mandibular Canine Mandibular Incisors

What happens when the jaws are not in this relationship? If the mandible is much shorter than the maxilla, the lower incisors and canines will impact onto the roof of the mouth and dig into it. This will mechanically impede the growth of the mandible leaving it permanently short or causing it to bend in the middle and bow out below.

This dog has some adult teeth and some deciduous teeth. The canine teeth are all deciduous teeth.

Deciduous teeth might look small but they are very sharp! When they dig into the soft tissues inside the mouth it creates a great deal of pain for the puppy. Often these puppies become very head shy and reluctant to allow anyone to look into the mouth. They may not eat well due to the pain and this will affect their growth.

What can be done? Removing the teeth that are impacting on the inside of the mouth has two benefits. First, it will immediately relieve the pain. Second it will allow the short jaw the opportunity to grow. However, there is a big time constraint. The adult incisors will start erupting at 3-4 months of age, and very quickly grow enough to impact the tissues on the inside of the mouth again resulting in impeding the growth of the jaw.

These mandibular deciduous canine teeth (green arrows) are digging into the hard palate. Sometimes if the mandibular canine is close to where it should be, the soft tissue in the area can be removed, allowing the canine to go into a more normal position.

This is the same dog as in the Normal Bite in a Dog picture. This puppy was lucky, as his malocclusion was not too severe. Early treatment allowed his mandible to grow a bit longer.

Early consultation with a veterinary dentist will give the puppy the best chance to grow out a normal mandible. As time goes by, this growth will no longer occur and other procedures will need to be used to result in a painfree mouth.

Dr. Waugh is a graduate of the University of Pennsylvania School of Medicine. She also holds a Masters Degree from Washington State University of Veterinary Medicine and is owner of Windsor Pet Dental, PLC.