Discolored Pet Teeth

What is it?

You may have heard of dead, discolored, or non-vital teeth; they all describe one thing: any pet tooth that is not the standard color is almost certainly dead and infected. This means that teeth which are purple, yellow, grey, or brown are very likely to be a significant problem for your pet.

In fact, a study showed that 93% of discolored teeth are dead and infected.

In our experience, it’s even higher. Unfortunately, dogs and cats rarely show obvious signs of oral pain. Therefore they often go untreated.

Source of Problem

Any tooth which is not the normal color from the inside is considered intrinsically stained. This occurs when blood is forced into the dentinal tubules during pulp death. In essence, you see a tooth bruise.

The main reason for this is blunt trauma of sufficient force to cause pulp hemorrhage but not enough to fracture the tooth. However, there is often no history of trauma, and this can happen for other reasons. The extravasated blood is forced into the dentinal tubules where it degenerates.    A tooth stained by degenerating blood products following pulp hemorrhage appears pink immediately after the injury, eventually becoming darker brown or gray. (Figures 1 & 2 below).  Studies and our clinical experience are that the vast majority of discolored teeth are dead. Once the tooth becomes non-vital, it typically becomes infected via the blood supply. Once the tooth becomes infected, it acts as a bacterial fortress allowing the bacteria to infect the entire body.


Clinical observation is diagnostic. Dental radiographs should be exposed to determine the condition of the roots.   Non-vitality is proved by a change in the width of the endodontic space or periapical lucency. A larger root canal diameter (Figures 3) than the contralateral tooth indicates pulp necrosis. Radiographic evidence of a smaller diameter root canal space than the contralateral tooth indicates generalized pulpitis. Periapical lucency is evidence of endodontic infection-causing bony resorption. (Sees Figures 3  & 4) However, normal radiographs do NOT mean that the tooth is not dead and infected.

Recommended Treatment

Discolored teeth are dead and infected and should be treated with root canal therapy or extraction. For larger teeth such as canines and carnassial teeth, root canal therapy is the treatment of choice. (Figures 5 & 6) For small teeth such as incisors and premolars, extraction is a viable alternative, but root canal therapy is also indicated if the client wishes to save the tooth.

Following root canal therapy, a full coverage cast metal crown is recommended to strengthen the tooth.

Figure 1
Intrinsically stained maxillary P4
Figure 2
Intrinsically stained canine
Figure 3a
Radiographic evidence of non-vitality of the teeth in figures 1 and 2.
These teeth have been non-vital for a significant period of time as evidenced by the widened endodontic system (blue lines). There is secondary infection as shown by the periapical rarefaction (red arrows).
Figure 3b
As above radiographic evidence of non-vitality of the teeth.
Figure 4
Extracted mandibular canine and maxillary P4 in a large breed dog demonstrating the size of the roots.
Figure 5
Post operative root canal.

At VDS we offer these services to address discolored teeth

Root Canal Therapy
Root canal therapy involves the removal of the pet's diseased or infected root canal system (nerve). The most common indication for pet root canal therapy is a fractured tooth. Other indications are discolored (dead) teeth or abscessed teeth.