What is an Oro-Antral Communication (OAC) and an Oro-Antral Fistula (OAF)?
In order to understand what an oro-antral communication is, we need to first explain a couple of terms. ‘Sinus’ and ‘antrum’ are abbreviations for the ‘maxillary air sinus’ and ‘maxillary antrum’ respectivey. They actually mean the same thing- that is the air space in your top jaw, that is connected to your nose. It is the one that gets blocked when you have a cold or that gives you pain during sinusitis.
An oro-antral communication is a potential complication of an upper molar extraction. If you have particularly large roots on your upper molar teeth, they can sometimes extend beyond the jawbone into the sinus. This means that if an extraction is required, the hole that results when the tooth is removed connects your mouth (‘oro’) with your antrum (‘antral’), which together make an ‘oro-antral communication’ or an OAC for short.
If I have an OAC, what will happen?
Two things can happen:
- It can heal– As usually happens with the appropriate care
- An oro- antral fistula forms– Here the gum in your mouth and the lining of your nose cavity grow together to form a non-healing tunnel between the two (known as a ‘fistula’). This happens in 0.5% of cases and requires further surgery to close.
What are the Signs and Symptoms ?
These will vary somewhat depending on the size of the ‘communication’ but include:
- A non- healing (empty) socket
- Pain initially – over time it would only be painful if there was an added infection
- Escape of air or fluid into the mouth from your nose
- Escape of food or fluid from your mouth up into your nose
- Sinusitis- caused by saliva and bacteria from your mouth getting into your nose
- Pain and tenderness of the area under your eye/upper cheek
- A blocked nose and discharge on the one side.
The Classic Complaint
A dull throbbing pain in your top jaw on the one side only. The pressure seems to go up to your eye and most of your upper teeth on that side; the teeth are tender on biting. You may have noticed a runny nose and that your nose is blocked on the one side. The pain has lasted for a couple of weeks following an upper molar extraction and is now disturbing your sleep.
What Investigations will the Dentist do?
- X-rays will be taken, before the extraction, to assess how the roots of the tooth lie in relation to the sinus. If you return with this classic complaint, another view may be taken to rule out other problems, or to check if there is some root fragment which has made its way into the sinus.
- Other teeth. Any problems with other teeth must be ruled out.
- Air bubbles. The dentist will look for air bubbles in the socket when you breathe in through your nose- a sign that your nose and your mouth are connected up.
- Suction tip. If the dental sucker, which mops up all your saliva is held over the socket, a wind tunnel sound may be heard, as air is sucked down from the antrum.
Some dentists may very gently probe the area, or get you to gently blow your nose. However, most would be against this as it could worsen any connection, or if done too firmly create one if the lining of the antrum was still in tact.
What Factors put you at Risk of an OAC?
- Large sinus
- Large and unfavourable shaped roots extending into the sinus
- Dry socket or poor healing
- Being older (over 40)
- 1st and 2nd upper molar teeth extraction
- A difficult extraction
- Infection, abscess or cysts associated with the tooth being removed
- Periodontal disease (significant bone loss)
- Hypercementosis- an excessive build up of cementum (one of your tooth layers like enamel or dentine) which gives the tooth a fat appearance.
How do you Treat an OAC?
The dentist may suspect a communication, or one may have been confirmed. Either way, the advice is similar- you should follow their instructions which are aimed at preventing a rise in air pressure in the sinus. If this happens, for example by sneezing or blowing your nose, air will be forced down into the mouth, through the hole and it may worsen or prevent the communication from healing.
- Do not blow your nose
- When you sneeze allow air pressure to escape out of your mouth- don’t hold it in
- Use a decongestant or the one prescribed by your doctor/dentist
- Use an antibacterial mouthwash like chlorehidine (Savacol) – but not for the first 24 hours while the clot establishes
- Follow all extraction aftercare advice.
There is a risk, that a piece of root can fracture off the tooth move into the sinus and cause problems. If a root has been displaced into the sinus, it can sometimes be removed through the socket- if it is still under the lining of the antrum. If not, a different and more difficult surgical procedure such as a Caldwell- Luc approach may be needed. Referral to an oral surgeon will be necessary to have this done.
As we mentioned at the start, the communication will either heal spontaneously, or form a fistula. If a fistula forms then a small surgical procedure can be done to close the connection. This involves a flap of gum being raised and gently stretched across the socket to cover the hole- it is then secured in place with stitches.