What Is Oroantral Communication (OAC)?
Oroantral communication (OAC) is a gap between the maxillary sinus and the oral cavity due to a pathologic process. If left untreated for an extended period, this condition can lead to the development of oroantral fistulas, maxillary sinusitis, and other sinus infections.
Oroantral communications are often attributed to an iatrogenic cause or operator-induced injury due to traumatic extraction of posterior maxillary teeth, most commonly the maxillary premolar tooth area (antral teeth), as the inferior wall of the maxillary sinus is closer to the roots of the maxillary premolars and molars. The distance between the apex of the tooth and the sinus is usually around one to seven millimeters for an individual with sinus floor thickness from two to three millimeters.
What Are the Causes of Oroantral Communication?
The oroantral communication is observed in 1.3 - 3.8 % cases of maxillary molar extractions, and the cause can be either traumatic extraction or iatrogenic injury to the sinus floor. Moreover, oroantral communications can also be caused by other surgical procedures such as tumor resection surgeries, dental implant surgery, trauma surgeries, or orthognathic surgeries involving the maxilla.
What Is Oroantral Fistula?
An oro-antral fistula (OAF) is the most common type of epithelialized pathological communication between the oral cavity and the maxillary sinus. This occurs when the oroantral communication fails to close or is left untreated over time. This passage results in the migration of oral epithelium and usually occurs when the perforation persists for at least or longer than 48 - 72 hours. Within a few days, the epithelialization of the fistulous tract takes place alongside the inflammation of the surrounding bony margins (osteitis). Additional findings like the presence of foreign bodies and the development of maxillary sinusitis may also be found.
When the pathology is left untreated, it can turn into chronic fistula formation. The average time an oro-antral perforation takes to epithelialize and turn into a chronic fistulous tract is approximately seven to eight days. The oro-antral fistula can be classified into three forms based on the location, which are -
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Alveolo-sinusal oro-antral fistula.
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Palatal-sinusal oro-antral fistula.
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Vestibulo-sinusal oro-antral fistula.
What Are the Clinical Features of Oroantral Communication?
Patients with oroantral communication or oroantral fistula usually complain when there is nasal regurgitation of liquids. Some of the other clinical features involved in this condition are -
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The nasal resonance may get altered, and the patient may find difficulty sucking through a straw.
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There may be unilateral nasal discharge and foul or bad taste.
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Some patients also complain of whistling sounds when they speak.
How Oroantral Communication or Oroantral Fistula Diagnosed?
It is also possible that many patients affected with oroantral communication may be asymptomatic. Upon clinical inspection, a dental surgeon can easily diagnose large oroantral fistulas. But in the case of small fistulas, the nose-blowing test is done.
Nose Blowing Test -
In this test, the patient is asked to close both nostrils and blow down gently from the nose with an open mouth. If an oroantral communication is present, it may be diagnosed by a whistling sound of air that passes down the fistula into the oral cavity or even as air bubbles, blood, or mucoid secretions around the nasal orifice. Additionally, a mouth mirror placed at an oro-antral fistula or communication can also cause fogging of the dental mirror.
Radiographic Examination -
1. Two-Dimensional Radiography -
Two-dimensional imaging modalities greatly help the dental surgeon identify the cause of the discontinuity of the maxillary sinus floor, the size of a bony defect, or even the disruption of the sinus borders. Periapical radiographs have been used over many decades to diagnose or identify foreign bodies that get dislodged into the maxillary sinus. Other two-dimensional imaging techniques like panoramic or occipitomental radiography can also help visualize the maxillary sinus and the oroantral communication pathway. But the major limitation of two-dimensional imaging remains the superimposition of structures anatomically as compared to three-dimensional radiographic imaging.
2. Three-Dimensional Radiography -
Three-dimensional radiographs such as computed tomography (CT) and cone beam computed tomography (CBCT) are essential tools for the diagnosis of oroantral communication. These three-dimensional imaging modalities help find any discontinuity in the maxillary sinus floor and the size of the oroantral communication. Any foreign bodies, bony defects, or mucosal tissue surrounding the oroantral communication can also be visualized accurately.
What Is the Management of Oroantral Communication?
A. Surgical Strategy -
The treatment of oroantral communication depends upon the size of the perforation. Communication of less than two millimeters in diameter is self-limiting and does not require any surgical treatment.
In cases with opening more than two millimeters, some of the following surgical procedures can be done, such as gingival suturing, soft tissue grafting, flap surgery, and implanting hemostatic gauze to close the gap. Common soft tissue grafts include palatal rotational flaps, palatal transposition flaps, or buccal advancement flaps.
Preoperative to Surgical Strategy -
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The maxillary sinus is first irrigated with normal saline, followed by an iodine-containing solution diluted with normal saline (1:1; betadine solution ) to eliminate the infection.
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This regimen is administered until the lavage fluid turns clear or does not contain any form of inflammatory exudate.
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Post this surgical graft techniques can be performed using xenografts, allogenous grafts, or autogenous grafts (from areas of the chin, retromolar area, or cartilage of septum).
B. Non-surgical Strategies -
The non-surgical treatment plan for oroantral communication includes allogenous materials without flap closure, such as fibrin glue or synthetic bone graft materials. Other non-surgical treatment methods for smaller oroantral communication include root analogs, acrylic splints, or tissue biostimulation using powerful lasers.
C. Pharmacological Interventions -
Medicines are given alongside non-surgical or surgical treatment ranging from antibiotics to nasal decongestants to relieve clinical symptoms. Antibiotic therapeutic drugs like Amoxicillin and Clindamycin are considered the most effective for relieving oroantral communication. At the same time, nasal decongestants are used as adjuvant therapy in patients who also suffer from sinus infections.
Conclusion:
To conclude, oroantral communication should always be treated within time to prevent further complications such as fistula formation, sinus infection, and other potential facial space infections.
