Referral & Clinical

Pulp Damage

Grey or purple teeth – non-vital pulp

The veterinary surgeon needs to be aware of teeth whose damage is less dramatic than a fracture but whose need is often greater.

Discoloration of a tooth is normally due to trauma to the pulp and subsequent bruising leading to haemorrhage within the canal. This can be from external trauma to the tooth, which may have subluxated, the tooth within the alveolus sufficiently to cause rupture, and subsequent ischaemic necrosis, of the pulp. The iron within haemoglobin combines with sulphides to form iron sulphide, which then lodges within the dentin tubules to cause a purple or black colour. In addition, a pulpitis forms which may be reversible or can lead to pulp death.

Pulpitis is hard to demonstrate in dogs, as it requires an accurate response from the patient to concussion and temperature tests. In general I use radiographs to assist. Pulpitis cannot be seen on a radiograph but the effects can be over time.

If the pulp dies, the odontoblasts within the canal also die. The dentine walls no longer thicken compared with the opposite teeth and, as necrosis ensues, the appearance of the pulp changes from a homogenous ground glass appearance to a more patchy density. An apical lucency/granuloma/abscess may also be visible. At the very least, these teeth should be radiographed to demonstrate any current pathology. If none is present, a further radiograph some 4-6 months later will show evidence of change or, more accurately, lack of it.