May 2008
Dr Gerhard Steenkamp

An 8 year-old Thoroughbred gelding is presented with head shaking and fighting with his bit.  Your extraoral examination is unremarkable.  While performing the oral examination you see the following:

a) What is your diagnosis?

b) What is the pathogenesis of this lesion?

c) What treatment options are available?

Memo

a) There is a hook on the rostral aspect of the left maxillary 1st cheek tooth (premolar 2).

b) Equines have hypsodont teeth (meaning there is a reserve crown in the jaw bone) that continuously erupt throughout life.  As soon as the opposing teeth come into contact they wear each other down at a constant rate.  This rate is dependant on the food the horse has access to.  When 2 opposing teeth do not have a 100% crown overlap (i.e. mandible shorter than maxilla in this case), only part of the tooth will be abraded (worn away) and that part which is not worn away will continue to elongate.  Should this condition be left untreated the tooth may elongate to the extend that it can penetrate the mandible

c) These hooks need to be removed. . This can be done with a short straight float, an S-float or a motorised diamond disc float.  These teeth are extremely hard and when faced with a case as seen on the photo, you will need to remove most of the hook first before attempting hand floating.  This can be done with an Equichip chisel or embryotomy wire.  Motorised diamond disc floats on their own can also be used to remove excessive hooks.