Oro Antral Fistula

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 & 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 / tuberosity
  
• Thickened tooth cement / tooth fused to jaw bone
  
• Infected teeth / long-standing decay
  
• Marked periodontitis / gum disease
  
• Lone-standing
  
• Previous history of OAC’s.
  

Treatment of the Acute OAF:

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