What is it?
The roots of the upper molars and premolars rest against the floor of the maxillary sinus. If this thin floor comes away with the root during an extraction, a connection forms between the mouth and the sinus. In its fresh state, in the first days, it is called an oroantral communication; if it does not close and its inner surface becomes lined with mucosa, it turns into a permanent channel, an oroantral fistula.
You usually notice the signs yourself. Water or mouthwash comes out of the nostril on the same side, you feel air escaping as you speak, and smoking or drinking through a straw becomes difficult. A blocked nose on the same side, a bad smell and a bad taste in the mouth can be added to this. The symptoms may not start at the moment of the extraction, but a few days later.
The size of the opening decides how things go. Connections up to about two millimetres are expected to close on their own as long as the clot is protected. In wider openings, and in fistulas that have gone past three weeks, closure on its own is not expected; here the sinus stays in contact with the flora of the mouth, so the risk of infection rises.
Signs
You will not necessarily have all of these at once.
Why does it happen?
- 01
Extraction of upper molars and wisdom teeth
In teeth whose roots reach into the sinus and are splayed or curved, the thin bone of the sinus floor can come away with the root. Difficult extractions and roots that break increase this possibility.
- 02
Cysts and large inflamed lesions at the root tip
A cyst or granuloma at the root tip may already have dissolved the bone in the floor of the sinus. When the lesion is removed, an area with no bone covering it is left behind.
- 03
Surgery in the sinus area
Placing an implant, sinus floor elevation and retrieving a root fragment pushed into the sinus can all open the border between the mouth and the sinus. These procedures are planned with a CT scan beforehand.
- 04
Loss of the clot after the extraction
In the first days, blowing your nose hard, drinking through a straw, smoking and rinsing your mouth vigorously move the blood clot out of place. A small opening that would have closed on its own can then stay open.
How does it progress?
- Fresh opening
A connection noticed during the extraction
The dentist checks the area straight after the extraction. A stitch placed at the same appointment and a protected clot most often stop the opening becoming permanent.
- Small
An opening up to two millimetres
As long as the clot stays in place, it is expected to close on its own. Not blowing your nose and avoiding any sucking movements are decisive in this period.
- Wide
An opening of five millimetres or more
Closure on its own is not expected. Surgical closure with a soft tissue cover is planned; the earlier the procedure is done, the easier it is to protect the sinus.
- Fistula
A passage that has become permanent
An opening that has gone past three weeks becomes lined with mucosa on the inside and does not close by itself. Before closure this tissue is removed, and any infection in the sinus is dealt with.
How is it treated?
If the opening is noticed during the extraction, the first aim is to keep the blood clot in place. The area is closed with stitches and, if it is thought necessary, a dissolvable plug is used; you are told not to blow your nose, not to use a straw and to keep your mouth open when you sneeze. Following the rules in this period directly affects the outcome.
Surgical closure is carried out for wide openings and for those that do not close on their own. A soft tissue flap prepared from the cheek or the palate is brought over the opening and stitched so that it is not left under tension; where a fistula has formed, the tissue lining the channel is cleaned away first. The procedure falls within oral and maxillofacial surgery.
If infection has settled inside the sinus, it is dealt with before the closure or alongside it, and an ENT specialist's assessment may be asked for at this point. After closure, you are expected to attend the stitch check, to take the medicines you are given regularly and to stay away from anything that builds up pressure for two weeks.
- Facial pain and swelling of the cheek on the same side, rising along with a temperature
- Pus coming from the nose or from the extraction site
- Swelling and redness around the eye
- A clear increase in food and liquid passing into the nose
How is it prevented?
- Before upper back tooth extractions that look difficult, ask for the relationship between the roots and the sinus to be assessed with imaging.
- Do not blow your nose for two weeks after the extraction; keep your mouth open when you sneeze.
- Do not drink through a straw, do not smoke and do not play a wind instrument; sucking and blowing movements lift the clot.
- If you notice water going up your nose as you drink, do not put off the check-up; closing it early is a smaller procedure.
Frequently asked questions
- Will an opening between the mouth and the sinus close on its own?
- In small openings it is expected to close as long as the clot is protected. In wide openings and in fistulas that have gone past three weeks, closure on its own is not expected, and surgical closure comes onto the agenda. The findings of the examination and the imaging decide.
- How can I tell at home that there is an opening?
- Liquid coming out of the nostril on the same side while you drink is the most familiar sign. Do not test it yourself by holding your nose and blowing; this movement can make the opening bigger. When you suspect it, see your dentist, where the assessment that is needed can be done safely during the examination.
- Can an implant be placed after the opening is closed?
- Once the area has healed and the sinus has settled, the implant plan can be looked at again. If there is not enough bone height, extra procedures such as sinus floor elevation come onto the agenda. This decision is made according to how healing goes and what the imaging shows.
This content is for general information and does not replace an in-person examination. Symptoms overlap between conditions, and a diagnosis can only be made clinically.