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What is an Oro-Antral Communication (OAC)?

This is a communication between the maxillary sinus / antrum and the oral cavity / mouth.

What is an Oro-Antral Fistula?

If an OAC is not treated, this can become lined with epithelium (skin). Hence, an oro-antral fistula is an epithelised tract linking the maxillary sinus to the mouth; the tract becomes ‘permanent’.

(Alternative names for an OAC / OAF include oro-antral fistulæ & oral fistulæ, sinus perforations and antra-oral fistulæ).

When an OAC is created, it allows the flow of food, smoke or fluid from the mouth into the nose. Not just these but also bacteria, fungi and viruses. This can set up a maxillary sinusitis, which depending on how long the communication lasts for, may either yield an acute / chronic maxillary sinusitis.

Causes of OAC’s:

The vast majority of OAC’s are created when upper molars and premolars are removed (almost 50%), tumours (18.5%), bone infections (osteomyelitis) (11%), operations to access the maxillary sinus (Caldwell-Luc procedures) (7.5%), trauma (7.5%), dentigerous cysts (3.7%), correction of septal perforations (3.7%), perforation of the sinus floor from the tooth socket when trying to remove an upper tooth and localised florid gum disease (HIV-related periodontitis) or tooth-tip infections (chronic apical infection).

Predictive Factors:

As a very broad generalisation, the following may be thought to predispose to an OAC being formed:

  • Proximity of sinus floor / tuberosity
  • Thickened tooth cement (hypercementosis) / tooth fused to jaw bone (ankylosis)
  • Infected teeth / long-standing decay
  • Marked periodontitis / gum disease
  • Lone-standing
  • Previous history of OAC’s.

Treatment of the Acute OAC:

If an OAC has been created, then:

  • Do not probe the defect
  • Promote good blood clot
  • The gingival / gum margins around the socket should be approximated as close as possible
  • Physical agents placed in the socket to stop excess bleeding (Surgicel, Spongostan or Haemocollagene)
  • Antibiotics should be prescribed (Amoxycillin, Doxycycline)
  • Nasal decongestants can be used (Ephedrine nasal drops, Oxymetazoline)
  • Steam inhalations can be used (Menthol & Eucalyptus)
  • Antiseptic mouth-wash should be used (Corsodyl)
  • No nose-blowing or smoking

How to Recognise the Chronic OAC / OAF:

The OAC is likely to become chronic if:

  • OAC is greater than 5mm in diameter
  • Gingival tissues / gums around the socket can’t be approximated
  • Post-op régime is not followed
  • Wound dehiscence / breakdown
  • Enucleation of a dental / dentigerous cyst
  • May develop 4 – 6 weeks post-extraction
  • Problems with smoking, eating or drinking
  • Cacogeusia / foul taste
  • Chronic maxillary sinusitis
  • Antral polyp herniating into the mouth
  • Purulent (pus) discharge from nose

Treatment of the Chronic / Larger OAC / OAF:

  • The OAC is assessed with X-rays & CT’s.
  • The OAC may still spontaneously close if a cover plate used.
  • If the OAC / OAF needs closing, pre-op antibiotic & decongestant régime (starting 3 – 7 days pre-op).

The OAF is closed using the following flaps:

Buccal Flaps:
Buccal Advancement Flap most common. Described by Rehrmann & made popular by Berger.

Palatal Flaps:

  • Palatal Rotational Advancement Flap most common.
  • Others include Palatal Pedicle Island Flap (Henderson),
  • V-shaped Palatal Flap (Krueger) &
  • Split-Thickness Palatal Flap (Ito & Hara).

Post-op Régime:

  • Antibiotics (Amoxycillin, Doxycycline)
  • Analgesics
  • Nasal decongestants (Ephedrine nasal drops, Oxymetazoline)
  • Steam inhalations (Menthol & Eucalyptus)
  • Antiseptic mouth-wash (Corsodyl)
  • No nose-blowing or smoking