Why ?

Just as you and I would want to correct a painful malformed joint,  or drain an infected wound, we should also want to relieve pain, control irritation, and reduce infection in our pets’ mouths. When the pain, irritation, and infection are caused by misaligned teeth, the modes of treatment fall into the category of orthodontic therapy. Orthodontic procedures are simply the tools used to improve function and reduce pain.

Teeth that are crowded, rotated, or tilted at abnormal angles will result in:

• early onset and increased severity of gum disease
• damage to the soft tissues of the mouth, due to sharp teeth penetrating unprotected gum and mouth tissues
• excessive wear, when abnormally aligned teeth grind against other teeth weakening the tooth structure
• pain, in the joints of the jaw as well as in the gums, lips, cheeks, and teeth

Genetic abnormalities and retained primary teeth are the main causes of misaligned or crooked teeth.  Genetically abnormal bites are typical and normal for breeds such as the bulldog, Shih‑Tzu, Pekingese, or Persian cat. Because dogs vary greatly in shape and body size, genetic combinations frequently cause differences in the length or width the upper or lower jaws.

Interceptive Orthodontics

Interceptive orthodontics is the “stitch in time saves nine” adage applied to growing mouths. Retained primary teeth will alter the eruption patterns of the permanent teeth. The primary tooth should always be shed as the permanent tooth cuts through the gum. When the root of the primary tooth does not dissolve, the tooth will remain firmly held in the jaw. The permanent tooth then “glances off” and erupts through the gum at an improper angle. Therefore, no two teeth of the same type should ever be in the mouth at the same time.

The retained teeth should be extracted as soon as the condition is recognized. If the extractions are performed early, the abnormally positioned adult tooth usually moves over to fill the void. Removal of the retained primary teeth is an inexpensive, simple way to prevent major problems from developing in the adult dentition.

If retained primary teeth have persisted past the time when the permanent tooth has fully erupted, it is sometimes possible to surgically reposition the permanent tooth into the void left by the extraction of the retained primary tooth. The timing of this technique is critical and it should not be attempted past the growth stage of the permanent tooth.

It is normal for the upper and lower jaw to grow at different rates. Even genetically normal dogs can occasionally develop abnormal bites due to the interlocking of primary teeth that develops during a growth spurt.  Selective extractions of the interlocked primary teeth will frequently allow the shorter jaw to grow unimpeded, and reach its full genetic potential.

Corrective Orthodontics

If, after the jaws have grown to their fullest extent and all primary teeth have been extracted, a significant misalignment still exists, then selective extractions of permanent teeth may be indicated.

In some cases, extraction of a permanent tooth can be avoided by reshaping the crown. Points of teeth that are damaging other teeth or mouth tissues can often be shortened with a dental bur and reshaped. If the amount of crown that must be removed is large and the pulp of the tooth would be exposed, then a partial root canal is performed.  In this procedure, a large amount of crown can be removed and the pulp chamber sealed to prevent pain and infection. Although it is more involved, this procedure is preferable to extraction when major teeth are involved.

When the preceding techniques are not applicable, or the misalignment is more complicated, then more sophisticated procedures are required.  Orthodontic tooth movement using brackets, buttons, acrylics, springs, and various elastics can be the treatment of choice.  In adolescent pets, tooth movements can be accomplished in as little as a week or two. Almost all veterinary orthodontic movements take less than 3 months. The retainer phase, so common in human orthodontics, is short and can often be eliminated altogether.

Even in human orthodontics, with cooperative patients who practice intensive hygiene, there are still many minor, but annoying, complications. Sometimes, the complications can be severe enough to endanger the survival of the teeth being moved.  Frequent visits are necessary to monitor progress and avert complications.

Patient Selection

Some pets are not good candidates for corrective orthodontic procedures. Young dogs explore almost everything with their mouth, so strict supervision is necessary to prevent damage to the orthodontic device. Some of the more “nervous” pets may paw at their mouths excessively and either damage or remove the appliance. The most frequent problem is the irritation of gums and cheek tissue caused by metal brackets or acrylic appliances.  Appliances allow food to become entrapped they may have to be cleaned daily. Rinses with an anti‑plaque disinfectant may be necessary to prevent gum disease while the apparatus is in place.

It is also important to be aware that the application, adjustment, and the removal of wires, brackets, and appliances will usually require anesthesia.