Dental A to Z
A permanent hole or opening in tissue through which fluid can drain. The most common type of fistula can occur during the extraction of an upper molar where the roots are very close to the sinuses. If the lining of the sinus is breached an opening (fistula) connecting the mouth to the nasal airways can occur. If this is not treated, the tissues can heal and leave an opening through which food can leak into the nasal area.