Pet Orthodontics

"Braces for my pet?" If needed, yes! Actually braces for our pets are not that common but poorly aligned teeth are. The primary goal of veterinary orthodontic therapy is to provide a comfortable and functional bite (occlusion) for the pet. There are many causes for pets to have malaligned teeth. Some of these include: retained primary teeth, tug-of-war play, genetic predisposition, nutrition, and tooth or jaw trauma.

Let's consider normal anatomy. Dogs have 28 primary teeth and 42 adult teeth. Cats have 26 primary teeth and 30 adult teeth. The primary teeth erupt between 3-12 weeks of age. These teeth are replaced by permanent teeth between 4-6 months of age.

Incisors are the small teeth in the front of the mouth between the large canine teeth. Dogs and cats have six upper and lower incisor teeth. The canine teeth are the large (fang) teeth located next to the incisors on either side. The incisors and canine teeth are used for grasping food and toys as well as directing the tongue in the mouth.

Next, the premolars are located on either side and in back of the canine teeth. Dogs have four upper and four lower premolars while cats have three upper and two lower premolars. Behind these teeth are molars. Premolars and molars serve to shear, cut, and grind food.

The way teeth align with each other is called occlusion. Normal occlusion in most breeds consists of upper incisors overlapping the lower incisors (blue arrow). This is called a scissor bite. As we move to the side of the mouth the lower canine tooth should be located between the upper lateral incisor and the upper canine tooth (green arrow) without touching either tooth.

Farther back in the mouth the lower premolars (red arrows) are located directly in front of their upper premolar counterparts. When viewed from the side, the lower premolars will interdigitate in the space between the upper premolars.

The final two points in the evaluation of a pet's occlusion are the pet's facial symmetry and angle of their temporal mandibular joint (TMJ). A Bite Evaluation Analysis may be performed for those dog owners interested in charting their breed for variations from their breed standard.

Note: The standards of some breeds of dogs and cats will allow for occlusions other than a scissors bite.

Pet Orthodontics

Classes of Occlusion

Before we discuss classes of occlusion, it is important to note that if a pets occlusion is abnormal with its primary teeth, it is very likely that the condition will still be present when the permanent teeth erupt. Therefore, it is during a pet's first six months that bite evaluations are essential to allow an early diagnosis and intervention.

Class 1 Malocclusion

These patients have normal jaw lengths and premolar teeth. In this class normally one or more teeth are malaligned. An anterior crossbite is an example of a malocclusion in which one or more anterior teeth are malaligned. This condition does not cause discomfort and does not require treatment. Base narrow canine(s) is a condition in which one of the lower canine teeth are angled inward and cause pain from the tooth striking the roof of the mouth or palate. A misdirected tooth (spear tooth) may.

Base Narrow Lower Canine

Class 2 Malocclusion

This refers to the condition in which the lower jaw is noticeably shorter than the upper jaw. Some people refer to this as an "overbite". Most of these patients will experience discomfort and benefit from therapy. In young pets the lower primary teeth (incisors and canines) are selectively extracted to allow jaw growth and to relieve pain. This is called interceptive orthodondotics.

Extracted Lower Teeth Canine

Base narrow canines may occur in Class 1 or 2 malocclusions. If the pet is between 4-7 months of age,. we can use the force of the erupting tooth along with a build-up of restorative material (red arrow) to direct the tooth into a proper location.

Erupting Dog Tooth

In the adult patient, treatment involves fabrication of an acrylic inclined plane that will direct the tooth to the proper position (red arrow).

Acrylic Inclined Plane

Another therapy is to shorten the crown and cap the tooth. Therefore the shortened tooth no longer strikes the palate or roof of the mouth (black arrow).

Pet Crown Reduction

Class 3 Malocclusion

This refers to a condition in which the lower jaw is longer than the upper jaw. Some call this condition an "under- bite". For some breeds like the Boxer, Bulldog, Shih Tzu, and Pug this bite is considered "normal" by breed standards. Pets rarely require treatment for this occlusion. In cases in which there is tooth to tooth contact (red arrow) extractions may be performed.

Conclusion

Hopefully this overview has provided you with a better understanding of normal and abnormal occlusion. Just as in people early therapy many times offers the best results. Watching the position of a puppies or kittens teeth in the first 6 months is the key!

We feel that orthodontic treatment plans, when needed, should favor the simplest therapy that will achieve the desired results - comfort and function.

Cases: