Causes of oroantral fistula
An oroantral communication (OAC) means an abnormal connection between the antral and oral cavities. A fistula refers to an unnatural passageway between the two surfaces lined with epithelial tissues. If OAC is not treated, the epithelial tissues may grow in it, leading to the fistula formation. The oroantral fistula (OAF) is an abnormal connection or opening between the maxillary sinus and oral cavity. This abnormal connection is the result of a number of factors, including the following:
- Maxillary sinusitis
Oroantral fistula and maxillary sinus disorder are related. Untreated chronic maxillary sinusitis predisposes to oroantral fistula formation. Even oroantral fistula may cause the sinusitis.
- Teeth related factors including extraction
- The most common reason is opening up the maxillary sinus by chance while extracting the maxillary tooth.
- During teeth removal, if the root or the tooth is forced into the sinus, oroantral fistula may form.
- Use of contaminated or diseased maxillary implant dentures forms the fistula.
- If the first maxillary molar tooth’s palatal root breaks during extraction, an oroantral communication channel may develop.
- During extraction, if a conical maxillary molar tooth slips into the maxillary antrum, especially along the tuberosity fracture, an oroantral perforation will form.
- A periapical lesion is an abnormality or injury around or at the apex of the tooth root. The lesion destroys the sinus floor, creating oroantral fistula.
- Occasionally, chronic periapical infection erodes the lamina dura of the root and then the apex and the sinus membrane come in direct contact.
- Surgeries
- When the incision line during Caldwell-Luc procedure does not heal, oroantral fistula may develop.
- Careless use of instruments during maxillary sinusitissurgery may perforate the sinus mucosa and floor.
- Maxillary sinus surgery performed for removing a big cystic lesion eating into the sinus cavity may lead to fistula formation.
- Marsupialization (surgical conversion of a closed cavity into an open pocket) performed on defective alveolar antral wall may also result in the fistula.
- Extensive facial trauma
- Extensive facial trauma, particularly, because of sharp objects or missiles inserted into the sinus via mouth will lead to oroantral fistula. Even gunshot injuries affecting the sinus walls badly create the fistula.
- Neoplasms
- Malignant granuloma and other malignant disorders of the maxillary sinus may erode the oral cavity.
- The tumors may penetrate the lateral wall of the sinus.
- Tumors of the upper jaw may reach into the sinus, forming the fistula.
- Damage to the maxilla due to teratoma, a group of tumors or a single tumor