Dentigerous/Odontogenic Cysts in Dogs

Why are missing teeth a concern?

Dogs normally have 42 adult teeth that should be fully erupted by seven months of age. If not, the missing teeth did not develop, have broken below the gum line, or remain unerupted . If a tooth is fractured, it can be a source of pain (often hidden well by your pup) and infection, and the remainder of the tooth needs to be removed to treat pain and potential infection. If the tooth is unerupted, it is at risk of forming a destructive dentigerous (odontogenic) cyst in the bone.

Why didn’t all my dog’s teeth erupt?

Unerupted teeth can occur for several reasons:

• Overcrowding (caused by normal-sized teeth in an abnormally small jaw)
• Abnormally thick gum tissue (gingiva) over the erupting tooth
• The tooth is positioned inappropriately or erupting in an abnormal direction
• The tooth’s eruption force is weak (possibly a genetic predisposition)

What are the clinical signs of unerupted teeth?

Although unerupted or broken teeth can be painful, dogs rarely show obvious signs of pain. Your veterinarian will need to take an intra-oral radiograph (X-ray) of the affected area(s) to determine if there is a tooth present, either in the form of broken roots or an unerupted tooth. 

Like human intra-oral or dental radiographs, the film will be positioned inside your dog’s mouth. Your dog will be anesthetized for the procedure to prevent injury to your pet. Your veterinarian will discuss this with you in more detail before the procedure.

Which teeth are most commonly unerupted?

The most common unerupted teeth in dogs are the first premolars (the first tooth behind the canine), the canines (the fangs), and the third molars (the teeth at the very back of the mouth—like human wisdom teeth).

Are some dog breeds more susceptible to this condition?

Brachycephalic (short-nosed) dogs, such as Boxers, Bulldogs, and Shih Tzus, and toy breeds (dogs under 11lb), like Chihuahuas and Yorkshire Terriers, are much more likely to have unerupted teeth and are at increased risk of dentigerous cysts. Boxers are also prone to having supernumerary teeth (more than 42); your veterinarian will check for unerupted teeth at the time of your dog’s spay/neuter procedure, which will help prevent dentigerous cysts from forming, regardless of the number of teeth in the mouth.

How are unerupted teeth treated?

Extraction is recommended in most cases of unerupted teeth because of the risk of a destructive dentigerous cyst. If detected early enough, your veterinarian may remove the gingiva (operculectomy), making it easier for the tooth to erupt. This tooth must then be monitored closely for normal eruption.  Your veterinarian will recommend the best treatment for your dog. This may include a referral to a veterinary dental specialist, especially if the location or position of the tooth compromises the ability to extract it entirely. Extracting unerupted teeth is the only way to prevent dentigerous cysts.

"Extraction is recommended in most cases of unerupted teeth..."

What happens if an unerupted tooth isn’t treated?

It is difficult to predict what will happen to an unerupted tooth. In some cases, no disease will develop; however, if there are several unerupted teeth, they will develop destructive dentigerous cysts. This happens when the outer developmental coating or follicle of the unerupted tooth becomes cystic, forming fluid-filled sacs that put constant pressure on surrounding bone, ultimately causing bone destruction. These cysts can grow large before they are detected visually, affecting the roots of the surrounding teeth and the integrity of the jawbone. Unfortunately, some cysts may not be detected until after the jaw has fractured.

How are dentigerous cysts treated?

Dentigerous cysts and the original tooth must be removed carefully to avoid compromising the bone, which can easily fracture during the extraction. Every bit of cyst tissue must be removed, or the cyst can continue to expand. This often requires the removal of any other teeth affected by the cyst. These are often referred to veterinary dental specialists for the best outcome.

Dentigerous cysts are preventable if unerupted teeth are addressed early in life.