If you need a more accessible version of this website, click this button on the right. Switch to Accessible Site


You are using an outdated browser. Please upgrade your browser to improve your experience.

Close [x]
(207) 846-6515 H

(207) 846-6515


An oronasal fistula is an abnormal space connecting the oral cavity and the nasal sinus. It can occur around any of the teeth in the upper jaw, but most commonly occurs around an upper canine tooth (the large front corner tooth). Oronasal fistulas can occur in dogs and cats, and are most common in dogs with a dolichocephalic head type - long, pointed nose. Dachshunds are, by far, the breed that is most commonly affected.

Causes   Oronasal fistulas are usually caused by periodontal disease that has progressed to the point where the bone of the tooth socket between the tooth root and the nasal sinus has decayed and disappeared. Less common causes penetrating injuries, electrical burns, and cancer.

Signs   There is usually significant periodontal disease, with tartar, gingivitis, and halitosis. There may be mucus and/or bloody nasal discharge. Some patients are painful and have trouble picking up and chewing food, treats and toys. Occasionally the problem is silent, and only discovered on the anesthetized oral exam.

When an oronasal fistula has been present for some time passage of material from the mouth into the nasal sinus results in nasal inflammation and infection and potentially pneumonia. 

Diagnosis   Sometimes the oral opening of a fistula is visible within the mouth. In most cases the space is so narrow that it can only be found by inserting a probe alongside the tooth root. Oronasal fistula is an unusual dental problem in the sense that x-rays often are not helpful in the diagnosis.

Treatment   Oral surgery is the only effective treatment option. The tooth adjacent to the fistula is extracted; decayed bone and gingival (gum) tissue is removed. A flap of healthy gum tissue and mucosa (the soft pink tissue lining the mouth) is created and sutured in place over the oral opening of the fistula. 

If a very deep pocket is present but has not yet become a fistula, guided tissue regeneration and bone grafts can be used to try to prevent a fistula from forming. Unfortunately, these procedures have an extremely high failure rate, and are typically much more costly than extraction. At this time (2012) we do not recommend them.

Prognosis   The success rate for surgical closure of an oronasal fistula is extremely high; statistical reports place it at about 90%. In our experience, if a flap fails the first time (which is not often) a second surgery usually works, probably because the first surgery stretches and strengthens the tissue used to make the flap, so the second closure can be made more securely. 

Prevention   Other than preventing oral trauma, prevention of oronasal fistulas is the same as prevention of periodontal disease. It is worth noting, though, that we have seen oronasal fistulas in Dachshunds whose dental care is excellent and whose periodontal disease is minimal; some individuals of this breed almost seem destined to develop them.

Yarmouth Veterinary Center


Office Hours

Saturday8:0012:00; Also, 4 pm Boarding Pick-up
Sunday4:00pmBoarding Pick-up
Day Open Close
Monday Tuesday Wednesday Thursday Friday Saturday Sunday
7:30 7:30 7:30 7:30 7:30 8:00 4:00pm
6:00 6:00 6:00 6:00 6:00 12:00; Also, 4 pm Boarding Pick-up Boarding Pick-up