Deciduous Teeth

One of the most common dental procedures that is performed on our young pets is the removal of persistent deciduous canine teeth. All of our pets have “baby” teeth, but only some of them need to have them removed.

What are they?

Dogs and cats, like ourselves, have two sets of teeth that develop during their lives. The first teeth that develop are the deciduous teeth – also known as “baby” teeth or “milk” teeth”. These teeth are followed at some time by the permanent teeth, or “adult” teeth.

The deciduous teeth are little replicas of the adult teeth that will come along in the future. However due to the size of the young animal’s mouth, there are not quite as many deciduous teeth in the mouth as there will be in the future.  In fact the premolars get their name not from being in front of the molars, but because they have a pre-cursor, namely they have deciduous teeth (except premolar 1!). Molars do not have deciduous precursors.

As cute (and as sharp!) as they are the deciduous teeth cannot remain functional for the whole of the animal’s life, so they are shed and replaced by the permanent dentition. The adult teeth start off as tooth buds at the base of the deciduous teeth, and so develop right below the deciduous teeth. As the permanent teeth start to erupt (emerge from the jaw) they induce resorption of the roots of the deciduous teeth. When this process is complete (performed by Odontoclasts – see Tooth Resorption) the remaining piece of the deciduous tooth falls out of the mouth….. in most cases. 

Client Handout

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Persistent Deciduous Canine Teeth

Here we see the deciduous lower canines still present whilst the permanent lower canines have started to erupt – much more narrow than they should be.

Persistent Deciduous Canine Teeth

We can see here the upper right deciduous canine is still present, even though the permanent upper right canine is coming through the gingiva. This makes the permanent canine erupt more forward of its normal position.

What problems occur?

Some deciduous teeth for some reason don’t undergo the proper root resorption required for their shedding. This will result in the deciduous teeth still being present with the permanent version of the tooth being erupted as well. This situation is a real problem for the young animal. The deciduous tooth is the one in the correct position. However to erupt, the adult tooth has had to emerge in an incorrect position. We commonly see this problem arise with the deciduous canine teeth.

The problems that occur are twofold:

  1. the two teeth are tightly jammed against each other, creating the perfect environment for accumulation of debris and increasing the likelihood of periodontal disease – often resulting in the loss of both teeth.
  2. the permanent tooth is in the wrong position so causing malocclusion problems.

These issues can be dealt with appropriately by extracting the deciduous tooth and leaving the permanent tooth. 

Deciduous teeth also can be fractured. This results in the same issues as a fractured permanent tooth. However the complicating feature with a dead, infected deciduous tooth is that there is a developing permanent tooth at its base, right where the infection of the deciduous tooth is being discharged! Fractured deciduous teeth must be extracted.

A deciduous tooth after removal that had died and become necrotic, causing a large tooth root abscess.
An extracted dead and necrotic deciduous canine tooth.

This is a deciduous tooth that had been broken. What we see above the gum is a small tooth with a bit missing and little black dot, indicating an open pulp. This lead to a tooth root abscess that caused a lot of pain for this dog.


For the best results the extraction of the persistent deciduous tooth should occur as soon as it is apparent that it is not going to shed normally and the adult tooth is erupting. This means that if the deciduous tooth is not “wobbly” and any part of the corresponding adult tooth is visible, then the deciduous tooth is removed. It does not mean:

  1. remove the deciduous teeth before the adult tooth erupts
  2. remove the deciduous tooth once the adult tooth is fully erupted.

Extraction of the deciduous tooth is not always a straight forward procedure. It is vitally important that all of the deciduous tooth is extracted. This is because it is the root of the retained deciduous tooth that is causing the problem, not the visible crown. The adult tooth has erupted beside the root of the deciduous tooth to get to where it is (in the wrong position). So removal of all of the deciduous tooth will allow the adult tooth to move as it continues to erupt.

If performed properly and there is still movement of the adult tooth (ie: eruption) the adult tooth will preferentially move across into the space left by the now extracted deciduous tooth – the correct position.


If your pet has not lost their “baby” teeth and the adult teeth are present, they should have the retained deciduous teeth removed. This will ensure you give your pet the best possible chance at having a healthy pain free mouth.

A persistent deciduous canine

Persistent tooth

This is a lower right deciduous canine or 804. It should have been lost, however it is still in place whilst we can see the permanent replacement is now erupted.

The site of a deciduous tooth extraction

Extracted tooth

The 804 has now been extracted from its socket.

The extracted deciduous tooth adjacent to its extraction site showing how large the root it.

Large roots!

We can see here the tooth that was removed, the 804. It has a very large root. This is why removal of these persistent teeth is not necessarily a straight forward procedure.