June 2007
Dr Gerhard Steenkamp

A 4 year-old German Shepherd dog is presented with a complicated fracture of tits left mandibular canine tooth (304).  This dog is a patrol dog and is used regularly.

a How will the dog’s performance be altered with a fractured or no canine tooth?
b What treatment is necessary to retain this tooth?
c How can the tooth’s performance be improved?
d Does a crown strengthen a fractured tooth?

Memo

a With a shorter tooth or a missing tooth the equal force distribution amongst the 4 canine teeth will not occur anymore.  All the forces will now be distributed between only 3 teeth which increase there individual risks for fracture

b Since the pulp of this tooth is exposed, root canal therapy is required to remove all the necrotic tissue and prevent a periapical abscess from forming.

c A crown can be placed on this tooth to increase the length a little bit in order for it to be more functional.  The crown cannot be restored to its full height as the forces on it will be too great and this may increase the chances of the tooth to refracture.  As a rule of thumb we usually increase the height by about 5-6mm above the fractured tooth height.  The crown will also have a metal insert that fits into the root canal to increase the surface area which will determine the strength of the fit.

d Dogs can go back to their normal work once a crown has been placed, but teeth are not stronger having a crown placed.  In order to fit a crown virtually all the enamel of a tooth needs to be removed to make space for the crown itself.  This means that more tooth substance is lost and therefore the tooth will be weaker.  A crown is a very good way of protecting what is underneath it, but not necessarily by improving its strength.