When we think about dental disease or dental problems in our pets, the image that comes to mind most often is that of an older pet. While this is normally a very safe assumption, and we most definitely see an increase in the prevalence and severity of periodontal disease as pets age, there are some conditions that we see with relative frequency in young puppies and kittens that should be addressed as soon as possible to avoid issues with their permanent dentition.
Most puppies end up in their ‘forever homes’ between the ages of 8 and 12 weeks. By this age, they should have their complete set of deciduous teeth (also called primary or baby teeth). They should have six incisors (the small ‘gnawing’ teeth at the front) in both the upper and lower jaw, four long canine teeth (‘fangs’), and three pre-molar teeth per quadrant (upper right, upper left, lower right, lower left). The permanent or ‘adult’ teeth develop at the root tips of the deciduous (baby) teeth, so if any of these teeth are absent, in all likelihood the adult tooth will not develop, either.
The adult incisors are the first to erupt at around 12 weeks of age, followed by the adult canines between 16 and 20 weeks of age, followed by the adult molars and premolars. While there are some exceptions, in general by seven or eight months of age, all of the permanent adult teeth should be fully erupted.
Will all that said, as with many things in life, things do not always go as we plan or as we’d hope. Particularly in small breed dogs and brachycephalic breeds (think those with a ‘smushy’ face such as the pug and bulldog), retained or persistent deciduous teeth are frequently seen. This is often an inherited problem, both by genetics and by the conformation of the skull. As we’ve bred dogs to be smaller and smaller, and with shorter muzzles, we’ve significantly decreased the amount of jaw space available to fit the same amount of teeth as they would otherwise have with a more ‘normal’ muzzle. The result of this is that the adult teeth grow beside the deciduous teeth instead of above, and therefore does not push the deciduous tooth out from the gum line or initiate the resorption of the root from the deciduous tooth.
There are numerous problems that can arise as the result of the two teeth being present, occupying a space that was designed for one. For example, the crowded teeth are often erupted with either very little or no gum space in between them, which creates a perfect tunnel for plaque and bacteria to accumulate and cause periodontal disease. This process or development of periodontal disease can occur quite quickly, and cause irreversible changes to the adult tooth and surrounding bone.
Another problem, most frequently seen with the canine or ‘fang’ teeth, is that the overcrowding causes the permanent tooth to erupt abnormally, often at inappropriate angles, which can result in very painful conditions by which the adult tooth bites into the gums or roof of the mouth. Advanced and potentially costly dental procedures are then required to correct this misalignment of the teeth, which may also involve the extraction of other adult teeth to make room.
Because of all of the negative impacts that persistent deciduous teeth can have on permanent adult teeth, as a general rule we should never see a permanent adult tooth and its relative deciduous tooth in the mouth at the same time. In other words, if we can see the adult tooth, the deciduous tooth should already have fallen out. If we do, it is most often in the pets best interest to have the deciduous tooth extracted as soon as possible, to allow the permanent adult tooth to erupt in its proper location and at the proper orientation.
As the proud new ‘parent’ to your new friend, you can be an important part of his or her veterinary team and keep a close eye on their dentition to ensure that they are developing appropriately, and this will be something that we will monitor as we see them for their puppy or kitten vaccines.
Below are a few cases that we’ve seen here at Westbridge with problems associated with retained deciduous teeth:
“Puppy” presented to us for a routine spay procedure. Upon physical examination by one of our veterinarians, there were a few abnormalities noted with her dentition. The one we will cover here was her retained deciduous tooth. Note that because it is occupying the space where the adult canine would normally erupt, the adult canine is pushed forward and erupting abnormally. The abnormal position of the canine at this point is not just simply cosmetic; these teeth are colliding with surrounding teeth, causing permanent enamel damage and gingivitis.
Prior to extraction, dental radiographs are very important to get an idea of the shape, size and length of the root of the deciduous tooth. The image to the right represents the tooth pictured above. The asterisks was placed to place emphasis on how little space there is between the adult canine tooth and its deciduous counterpart. The root was fully intact, and great care was taken during extraction so as to not damage the adult tooth.
The retained deciduous teeth were just the beginning of this puppies dental issues, and fortunately for us, some of the other pathology we found fits perfectly with the second part of this series – stay tuned later in the week for part 2!
