Oroantral Communication

Oroantral communication is a new, acute opening between the oral cavity and the maxillary sinus, usually found at the time of or shortly after an upper posterior tooth extraction, before the tract has epithelialised. It is the acute complication that precedes an established fistula.

It happens in about 0.3 to 5% of upper molar and premolar extractions, with higher rates for upper first and second molars, sinus floors that extend between the roots, and extractions that need bone removal or sectioning. A defect of 2 mm or less often closes without treatment, and larger defects need closure to prevent a fistula.

Pathophysiology. The thin bone between the root apices and the sinus floor, or the sinus membrane, is perforated during extraction, or the sinus floor is carried away with a root. Other causes are curettage of a periapical lesion, cyst enucleation and implant surgery.

A clot can seal a small defect. Larger defects stay open and allow oral bacteria into the sinus, leading to sinusitis and fistula formation.

At the time: bone fragment attached to the root, a hollow sound, a socket with a clear view into the sinus, and air or fluid passing between mouth and nose. Soon after: fluid in the nose when drinking, change in voice, air escape on rinsing, unilateral nasal discharge, facial pain or congestion, and a bad taste.

Many small defects are silent. Heavy bleeding from the nose on the same side is common after the extraction.

• Nose blowing test with the nostrils pinched at the time of extraction or at review: bubbling of air or blood through the socket confirms the diagnosis. A false negative can follow a blocked sinus.
• Inspection with good light and suction, and a blunt probe (a gentle, not forceful, passage), with care not to create or enlarge a communication.
• Periapical and panoramic radiographs: sinus floor, retained root fragments and bone loss. Cone beam CT where the size, a retained root, or sinus disease is in question.
• Sinus symptoms and signs at review: unilateral purulent discharge, facial pain, tenderness over the cheek.

Differential diagnosis.

• Established oroantral fistula
• Acute sinusitis of dental or nasal origin
• Retained root displaced into the sinus
• Alveolar osteitis
• Post-extraction bleeding with epistaxis
• Maxillary cyst perforating the sinus floor
• Neoplasm of the sinus

• Defect under 2 mm: allow the clot to form, with a resorbable haemostatic sponge in the socket, sutures to bring the margins together, and sinus precautions.
• Defect 2 to 5 mm: place a resorbable gelatin or collagen sponge or a collagen plug, and a figure-of-eight suture over the socket to hold it, with sinus precautions. Repeat the nose blowing test at 1 week.
• Defect over 5 mm, or a communication with a retained root or infection: immediate closure by a buccal advancement flap, with a tension free double layer closure, and removal of any root fragment from the sinus (by the socket or a Caldwell-Luc approach).
• Antibiotics for any communication: amoxicillin 500 mg orally three times daily for 5 to 7 days, or amoxicillin with clavulanic acid 500 mg and 125 mg three times daily for 7 days when sinusitis is present, or doxycycline 100 mg twice daily in penicillin allergy. Reduce when eGFR is under 30.
• Decongestant for 3 to 5 days only: xylometazoline 0.1% one spray each nostril up to three times daily, for no more than 5 to 7 days. Warm saline nasal irrigation.
• Sinus precautions for 2 weeks: no nose blowing, sneeze with the mouth open, no straws, no smoking, no vigorous rinsing or spitting, no air travel or diving.
• Analgesia: paracetamol 1 g every 6 hours (maximum 4 g daily) with ibuprofen 400 mg every 8 hours with food.
• Communication that persists beyond 3 weeks becomes an established fistula, requiring excision of the tract and flap closure.

Monitoring. Review at 1 week and 2 weeks, with a repeat nose blowing test. Persistent leakage or sinusitis at 3 weeks needs referral for fistula closure.

Referral and escalation. Refer to oral and maxillofacial surgery for defects over 5 mm, a retained root in the sinus, persistent leak or sinusitis. Urgent referral for orbital signs, spreading infection or suspected malignancy.