May 2007
Dr Gerhard Steenkamp

A 7 month-old Dachshund is presented for a wellness examination.  On performing an oral examination you noticed that the 1s and 2nd left maxillary incisors are discoloured (Picture 1).
 

a) What are your differential diagnoses for these lesions?
b) How would these lesions have come about?
c) What treatment options are available for these teeth

MEMO

a) Caries, Enamel hypoplasia/hypocalcification, trauma

b) Enamel hypoplasia/hypocalcification in this case would have been due to a localised traumatic event that took place before about 12 weeks of age.  The most common way is for puppies to be bitten by either littermates or the bitch during suckling.  The localised inflammation/infection will disturb the ameloblast cells during amelogenesis (enamel formation- hypoplasia) or it may interfere during the maturation phase of the enamel (hypocalcification).

A more generalised form of this condition may be present in puppies that had a systemic illness with pyrexia before 12 weeks of age (Picture 2).  In these patients all the teeth are generally affected.  Distemper virus is an epitheliotrophic virus that has an affinity for epithelial cells which include the ameloblasts (enamel forming cells).  That is why enamel hypoplasia/hypocalcification is common in these patients.  Practitioners should however realise that Distemper is just one of the causes for a generalised case of enamel hypoplasia and other causes of a pyrexia before 12 weeks of age should be excluded.

c) The aim of treatment in these patients is to protect the tooth from caries formation, and to prevent excessive tooth wear with ultimate pulpal exposure.  In order to achieve this owners are made aware that their dog’s teeth are not as strong as any normal tooth with enamel covering and therefore they should play responsibly with their pets.  No hard objects should be used for retrieving and no bones or cowhooves should be part of their diet (should it ever?).  A restoration of the tooth is not always possible before 18 months of age as the enamel in dogs is extremely this, and filling material will have to bond with the dentin.  To cut a decent cavity necessary for a filling the dentin has to age otherwise the pulp may be exposed when the cavity is prepared.  Caries in these teeth can be prevented my good daily oral hygiene.