In this condition, food and water regurgitate out the nose when the dog eats and drinks. The most common congenital cause is cleft palate. An infected tooth is the most common acquired cause. The canine teeth and fourth premolars in the upper jaw lie beneath the nasal passages. An abscessed tooth (usually a canine tooth) can rupture into the nasal cavity. The tooth falls out and the space it once occupied opens a passage through the hard palate that allows food to pass from the mouth into the nose.
The signs of oral-nasal fistula are a unilateral nasal discharge accompanied by sneezing, especially after eating.
Treatment: The problem is treated surgically by taking a flap of mucous membrane from the inside of the mouth and suturing it across the defect. Long-term antibiotics may be needed to clear up any infections.
Prevention: Proper dental care and prompt attention to any dental problems while they are still minor will help prevent oral-nasal fistula caused by tooth decay.