Malocclusion in Rabbits

The most common dental problem in rabbits and hares is malocclusion. Malocclusions are classified as atraumatic or traumatic.

Atraumatic malocclusion results from genetic malpositioning of teeth or due to dietary causes with insufficient attrition (Fig. 1 and Fig. 4). Traumatic malocclusions are the result of overgrowth of a tooth after the loss or fracture of the opposing tooth. Loss of proper attrition may lead to the same symptoms and problems as in atraumatic malocclusion.

The treatment of malocclusion is crown-height control to approximate the wear that would normally be experienced.

Crown trimming and reduction must be done with a diamond bur or disc, on a regular basis. The treatment should be repeated every 4-8 weeks until normal occlusion is reestablished, or in some cases for the entire life of the animal.

A tongue depressor or wooden spatula must be held behind the incisors to protect the tongue and other soft tissues during odontoplasty (re-contouring the crown of the tooth to reinstate normal aspect and occlusion)

The use of nail trimmers, tooth nippers, bone rongeurs, etc. should definitely be avoided, due to potential tooth fractures and fissures that could lead to infection.

If a pulp is exposed by crown trimming it can be treated in the same way as a fractured tooth. A calcium hydroxide paste should be placed to cap the pulp (direct capping) to form a reparative dentinal bridge.

The site should be closed with an intermediate temporary filling material to approximate the wear of the normal tooth Other materials such as amalgam  are not indicated due to their resistance to attrition. Crown reduction of the opposing tooth is necessary until the damaged crown grows to a correct length.

The only treatment that results in a permanent correction of malocclusion is the extraction of the involved teeth. In order to correctly evaluate the condition, shape and direction of the root, an X-ray in an oblique latero-lateral incidence is indicated where possible before the extraction (Fig. 2). Special instruments are needed such as the Remeeus/Fahrenkrug or Crossley/Fahrenkrug tooth luxators (Fig. 6).

Any attempts to extract the incisors without the proper instrumentation will definitely result in tooth crown or root fracture and lead to infections. In most cases incisor extraction is a quite challenging operation and its importance should not be minimized based on the perspective of low operation profit (the cost of this operation is not proportional with the time and effort spent).

The extracted teeth should be photographed as documentation (Fig. 3 and Fig. 5), and shown to the owner. They usually impress most animal owners with their incredible root length and sometimes curved shape.

After the extraction, normal pain control and sometimes antibiotherapy (depending on the general condition of the animal and the complexity of extraction) might be instituted. Rabbits can chew actually much better than before the extraction using just their cheek teeth (premolars and molars).
 

DDr. Stoian Camil, PhD, Dipl. EVDC