Oroantral fistula (OAF) is an epithelialised oroantral communication (OAC). OAC refers to an abnormal connection between the oral cavity and antrum (or maxillary sinus). The creation of an OAC is most commonly due to the extraction of a maxillary (upper) tooth (typically a maxillary first molar) closely related to the antral floor (floor of the maxillary sinus). A small OAC (up to 5mm wide) may heal spontaneously but a larger OAC would require surgical closure to prevent the development of persistent OAF and chronic sinusitis. Classification
Signs and symptoms of an OAC/OAF can include the following
When looking in the mouth, a communication in the upper jaw (i.e. a hole) can be seen connecting the mouth to the maxillary sinus. Sometimes this can be the only sign, as pain (+/- other symptoms) is not always present. Symptoms
· Same side nose blockage (unilateral nasal obstruction). When an OAC or OAF is present, the passage to the maxillary sinus can results in infection and inflammation in the maxillary sinus. This subsequently results in mucus build up presenting as a unilateral nasal blockage
· Sinusitis can progress – this can present as a pain in the midface. Pain can be referred to the upper teeth and be mistaken for toothache· Fluid can flow from the mouth through the communication and into the maxillary sinus.
- Panoramic radiographs can also be used to confirm the presence of an OAC. If simple radiographs are deemed not to give enough information, cone beam computed tomography (CBCT) (special x-ray equipment that can scan in 3 dimensions) may be used. Imaging can help locate the communication, determine the size of it and can give an indication as to whether there is any sinusitis and foreign bodies in the sinus. - Normally clinicians should be cautioned against probing or irrigating the site a newly formed OAC as this may reduce the chance of spontaneous healing. - Valsalva test (nose blowing test) The patient is asked to pinch their nostrils together and open their mouth and then blow gently through the nose. The clinician must observe if there is passage of air or bubbling of blood in the post extraction alveolus as the trapped air from closed nostrils is forced into the mouth through any oroantral communication. Gentle suction applied to the socket often produces a characteristic hollow sound. However, there are differing opinions about the appropriateness of carrying out this test. It can be argued that by performing this test, a small OAC may be made bigger thus preventing spontaneous healing. Causes
Extraction of maxillary teeth
The maxillary sinus is known for its thin floor and close proximity to the posterior maxillary (upper) teeth.