Water comes out of my nose when I drink: is there an opening between my mouth and my sinus?

At the back of the upper jaw, right above the roots of the molars and premolars, there is an air space called the maxillary sinus. In some people the bone between that space and the roots is as thin as paper; in others the roots stick out directly into the sinus. Taking out a tooth like that can leave a window into the sinus at the base of the socket the root sat in. According to a review of the surgical options, about half of these openings appear after upper molar and premolar extractions; the rest are linked to cyst and tumour surgery, implants, sinus floor elevation procedures and trauma.

Noticing the symptom is usually not difficult. Liquid coming back through the nose while drinking water or soup is the finding people describe most. It can be accompanied by these: not being able to drink through a straw, air escaping on that side while you speak with a whistling sound, your voice sounding as though it comes through the nose, one-sided discharge from the nose, a constant strange taste in the mouth and, if you smoke, smoke coming out of the nose. They do not all have to be present; liquid escaping is on its own reason enough to be seen.

The most important distinction here has to do with time, and it is rarely explained. A fresh opening is called an oro-antral communication; one that has been lined with epithelium and turned into a permanent channel is called an oro-antral fistula. The literature reports that when the hole stays open for longer than 48 to 72 hours, the epithelium at the edges starts to migrate inwards, and that the channel is lined on average within seven or eight days. Once the channel is lined, it no longer closes on its own: it has become a tunnel covered with mucosa on both surfaces, and closing it means removing that tissue surgically. In other words, going in the first few days and going in the third week are not the same procedure.

What really spoils the chance of closing on its own is a difference in pressure. Blowing your nose, sneezing with your mouth closed, drinking through a straw, smoking, playing a wind instrument and diving all push or pull the air in the sinus towards the clot in the socket; every time the clot shifts, the opening gets bigger. That is why the first instructions given to a patient waiting for closure are not about medicines but about behaviour.

Waiting has a quiet price. The same review relates that, with wide openings left unclosed, sinusitis developed in about half of patients within 48 hours and in about nine out of ten within two weeks. Bacteria from the mouth find a direct way into the sinus, and the sinus can no longer clean itself. Beyond that point, the job stops being the closure of a single hole and turns into treating an inflamed sinus as well.

The decision is largely given by the width of the opening. The literature quotes thresholds close to one another: openings smaller than two millimetres are reported to be able to heal on their own if the clot is protected, while openings wider than three or four millimetres are reported not to close on their own and to need closing. On where a suture stops being enough and a flap becomes necessary, the publications do not agree on a single limit in millimetres. The measurement is made by the clinician with a probe and on a CBCT scan; it is not a decision you can make by looking in a mirror.

The part of this that touches implant planning is the following: while there is an open or newly closed window in the floor of the sinus, sinus floor elevation, that is, a sinus lift, is not carried out in that area. The sinus has to be cleared first and the closure has to heal soundly. That in itself is an item of delay. In the method we use for patients whose loss has not stayed at a single tooth and who are missing many teeth, the implants anchor into the hard outer layer deep in the jaw, and raising the floor of the sinus does not come into it in most cases; patients who are suitable go home at the end of three clinical days with their final fixed teeth. Which of these applies to you is shown by a CBCT scan.

The two lists below do not make the decision; they show you which way you lean. The firm distinction is made by an examination, a measurement with a probe and a CBCT scan.

This is a problem belonging to a single tooth, and treating it is the job of the clinician who took the tooth out or of an oral and maxillofacial surgeon. The sequence below shows what to expect from the first examination through to confirming the closure.

1. 1

   Confirming that there is an opening

   The clinician looks at the socket and checks whether air bubbles or a frothy leak are coming from the edges. The classic method is the nose-blowing test: the nostrils are held closed and, with your mouth open, you blow gently while the clinician looks for air passing through. If a small mirror held in front of the opening mists up, that too shows there is a passage. Do not repeat this test at home; the pressure it creates can lift a fresh clot.

2. 2

   Imaging

   A panoramic X-ray gives the first idea; what shows the state of the sinus floor, the width of the opening and whether a root fragment has been pushed into the sinus most clearly is a CBCT scan. That image also reveals whether the sinus is inflamed.

3. 3

   Early closure of a fresh opening

   If only hours or a few days have passed since the extraction, the aim is to protect the clot and bring the edges together. With narrow openings, a suture and a dressing that holds the clot in place may be enough; with wider ones, a mucosal flap prepared from the cheek is slid over the opening and stitched.

4. 4

   Treating the sinus

   If the sinus has already become infected, closing the hole alone is not enough: an antibiotic, a decongestant and, where needed, an endoscopic procedure by an ENT specialist come into it.

5. 5

   Closing a fistula that has become chronic

   With a channel lined by epithelium, that tissue is removed first and the area is then covered with healthy tissue. The techniques mentioned most often in the literature are a mucosal flap advanced from the cheek, a flap rotated from the palate, and moving the fat pad in the cheek across.

6. 6

   Confirming healing and updating the plan

   The closure is known to have held when the liquid escaping stops and the tissue closes soundly. Once that is confirmed, how the gap in that area will be filled, and which plan suits you if an implant is being considered, are reassessed.

These are not competing with one another; depending on the width and the age of the opening and the state of the sinus, one of them is the right one. The list starts with the least invasive.

The points below are the things that can genuinely happen while you wait for the opening to close on its own. We are writing them so that you can ask the right questions whichever clinician you see.

The sequence below applies to the route that starts with closing the opening. The timings vary from person to person; the plan given by the clinician following you takes priority.

1. The first few days

   Tenderness and a certain amount of swelling in the area are normal. Eat soft food, do not chew on that side, do not rinse your mouth vigorously and take the medicines you were prescribed exactly as directed.

2. The first two weeks: the pressure rules

   The most critical thing in this period is not to create a pressure difference between the sinus and the mouth. Do not blow your nose, keep your mouth open when you sneeze, do not use a straw, do not smoke, do not play a wind instrument and do not lift anything heavy. If you have a flight or a dive planned, do not go without asking your clinician.

3. Confirming the closure

   Liquid escaping stopping completely and the tissue closing soundly show that the closure has held. The timing of the check-ups is set by the follow-up plan of the clinician treating you.

4. Returning to the implant plan

   If an implant is being considered for that area, the decision is made on a CBCT scan after the closure has healed and the sinus has been seen to be clear. Whether sinus floor elevation is needed also comes out on that image.

We do not give a single figure here, because with a fresh opening the job may end with a few sutures, while it may also take in clearing the sinus and flap surgery. These are the items that determine the scope:

The width and the age of the opening

A fresh, narrow opening and a chronic fistula lined with epithelium are not the same procedure; the second involves removing the channel and preparing a flap.

The state of the sinus

If the sinus is clear, the job is closure alone. If inflammation has settled in, or there is a root fragment inside it, treating the sinus comes in as a separate item.

How much imaging is needed

In some cases a panoramic X-ray is enough; a CBCT scan may be needed to clarify the width of the opening and the inside of the sinus.

How that gap will be filled afterwards

What is done in place of the missing tooth once the closure is finished is a separate decision; a single-tooth plan and a plan covering many missing teeth are not costed the same way.