Dog owners have been urged to be alert to a little-known dental condition that affects seven percent of dogs.
‘Shark teeth’ – officially known as persistent deciduous teeth (PDT) – is a condition in which two sets of grinders emerge from a row of gums.
It occurs when a dog’s baby teeth remain in the jaw instead of falling out when the adult teeth emerge.
According to veterinarians in a new study, the dog breed most likely to have PDT is the Yorkshire terrier, followed by toy poodle, Maltese and chihuahua.
PDT can cause a misaligned bite (“malocclusion”), which can cause the mouth to bleed, as well as an increased risk of periodontal disease and severe gingivitis.
‘Shark teeth’, officially known as persistent deciduous teeth (PDT), is a condition in which two sets of teeth emerge from a row of gums. This dog’s retained baby canines are circled in red. The two lower permanent canines did not grow exactly below the baby canines
The new study was led by Corrin Wallis, a research scientist at the Waltham Petcare Science Institute in Leicestershire.
‘Dogs use their teeth for a variety of tasks and therefore maintaining their oral health is vital to their health and wellbeing,’ say Wallis and colleagues.
‘Persistent deciduous teeth (PDT), teeth that do not fall out at the right time, are associated with malocclusion (misaligned bite), soft tissue trauma and an increased risk of periodontal disease.’
For the study, the team examined the medical records of 2.8 million dogs in the US over a five-year period, from January 2010 to December 2014.
The dogs were divided into groups based on their weight, from extra-small breeds (weighing less than 6.5 kg) to extra-large breeds (over 40 kg).
Overall, the prevalence of PDT, based on dog medical records, was seven percent among all weight groups.
In terms of individual breeds, Yorkshire terriers had the highest prevalence of PDT (25.1 percent), followed by Maltese and toy poodles (both 14.8 percent).
Meanwhile, the Greyhound had the lowest prevalence at 0.1 percent, followed by Rhodesian Ridgeback (0.2 percent).
PDT can cause a misaligned bite (‘malocclusion’), which can cause the mouth to bleed, as well as an increased risk of periodontal disease, a serious gum infection
Great Danes, English Bulldogs and Boxers also showed a low prevalence of the condition (all 0.4 percent).
Overall, the prevalence of PDT was generally found to be higher as breed size decreased.
A total of 15 percent of extra-small dogs had PDT, while less than one percent of all dogs in all categories heavier than 15 kg had the condition.
Why smaller breeds are more susceptible to PDT is unclear, but it could have a genetic basis.
Like humans, dogs have two sets of teeth during their lifetime: 28 baby teeth (baby teeth) and 42 permanent teeth (adults).
A dog’s baby teeth begin to erupt when he is three to six weeks old, and usually fall out when he is six months old.
At about three to five months of age, permanent teeth begin to appear.
When a permanent tooth follows a natural eruption path, it puts pressure on the top of the baby tooth.
“However, an incorrect eruption path of the permanent successor tooth or its complete absence can disrupt this resorption process and lead to PDT,” say the authors.
Shark teeth were also 11 percent more common in overweight dogs, although researchers aren’t sure why this is so.
Just like humans, dogs have two sets of teeth during their lifetime: 28 primary (baby) teeth and the permanent (adult) teeth of 42 teeth
The team wants owners of extra small and small breeds to be aware of the importance of regular veterinary checks, including an oral examination.
They say that especially for smaller breeds, it is crucial to have a thorough oral examination around six months of age to identify and remove any PDT.
“Once identified, PDT can be removed and if performed before six months of age, the likelihood of problems associated with PDT, such as the development of periodontal disease or malocclusion, can likely be significantly reduced,” they write.
The new study has been published in the journal Research in veterinary medicine.