An opening into your sinus after an upper extraction

An oroantral communication is a channel between your mouth and your maxillary sinus, left behind when an upper back tooth comes out and the thin floor of the sinus comes with it or tears. The roots of upper third molars often sit against that floor, and in some people they sit inside it with nothing but a sheet of bone thinner than a fingernail in between. When the tooth is delivered, that sheet can come away attached to the root. What remains is a socket whose deepest point is no longer bone but open air.

Two words get used for it and the difference matters more to your surgeon than to you. A communication is a fresh opening, hours or days old, lined by nothing. A fistula is the same opening after it has been open long enough — usually more than about three weeks — for the tissue to epithelialise, meaning the tract has grown its own skin-like lining and can no longer close by simply healing shut. That distinction is the whole reason this page insists you report the problem early rather than watch it. A communication is a smaller problem than a fistula, and it becomes a fistula by being left alone.

None of this means an error was made. The anatomy that produces it is visible on imaging beforehand and is discussed as a risk before upper third molar surgery, and it is one of the reasons a scan is sometimes taken. Reporting it is not an accusation. It is a normal post-operative message that changes what happens next.

The most reliable sign is something crossing between your mouth and your nose that has never crossed before. Water sipped slowly comes back out of one nostril. Air escapes upward when you try to draw on a straw, so the straw does not work. Your own voice changes, going nasal or hollow on one side, and some people hear a faint whistle on certain sounds. Any one of those is enough to call the surgeon.

The liquid sign is the one patients describe most often and the one they most often distrust, because it feels absurd the first time. A mouthful of water, taken normally while sitting upright, comes back down a nostril, usually a few seconds later and usually only on the operated side. It is more noticeable with thin liquids than with thick ones, and more noticeable leaning forward than sitting back. Milk and juice do it as readily as water.

The air sign runs in both directions. Blowing gently through the nose with the nostrils pinched can push air audibly into the mouth, out of the socket, and patients often notice this by accident while checking whether the first sign was real. Pinching and blowing hard on purpose is exactly what the next section asks you not to do, so if you have already done it once, stop there and report it rather than repeating it to be sure.

Voice change is subtler and more commonly noticed by other people. The maxillary sinus is a resonating chamber, and an opening into it alters how your voice carries. Some patients describe sounding like they are speaking into a jar. A whistle on the letter s, or on hard consonants, is a smaller opening announcing itself as air moves through it at speed.

There are also delayed signs, which appear when an opening has been present unrecognised for days to weeks. A persistent one-sided bad taste or smell, a discharge into the mouth that is not blood, a heaviness or pressure under the cheekbone that worsens when you lean forward, and one-sided nasal congestion that arrived after the surgery rather than before it. Those suggest the sinus itself has become involved, and they are a reason to be seen promptly rather than to wait for the next scheduled visit.

This is a page about recognising a pattern, not a page for reaching a conclusion about yourself. Several of the rows above overlap, more than one can be true at once, and the sensations that separate them are not reliably separable from the inside. What the table is for is deciding that the phone call is worth making, and it almost always is.

Blowing your nose raises the pressure inside your sinus far above the pressure in your mouth, and a healing socket floor is the weakest wall that pressure has to push against. A forceful blow can convert a bruised, intact floor into an open one, enlarge an opening that was going to close by itself, or blow out a clot and a repair that were holding. Sucking through a straw does the same damage from the other direction by dropping the pressure in your mouth instead.

The mechanism is worth holding onto because it explains every instruction in this section at once, rather than asking you to memorise a list. Anything that creates a pressure difference across the socket floor loads it. Positive pressure from the sinus side — nose-blowing, sneezing with the mouth shut, straining, playing a wind instrument, blowing up a balloon — pushes downward. Negative pressure from the mouth side — a straw, cigarette or vape draw, spitting forcefully, swishing a rinse hard — pulls upward. The floor does not care which direction the load comes from.

• Do not blow your nose. If it is running, wipe it. This holds for at least two weeks, and longer if you are told so.
• Sneeze with your mouth open, deliberately and every time. A sneeze through a closed mouth and pinched nose generates pressure in the same range as a forceful blow.
• No straws, and no drinking that requires suction, including from a sports bottle with a valve.
• No smoking and no vaping. Both involve a hard suction draw, and the draw is the part that matters here even more than the smoke.
• No spitting. Let saliva and blood-tinged fluid fall into a tissue or a basin instead.
• Rinse gently by tilting your head and letting the fluid fall out, never by swishing or gargling.
• Avoid heavy lifting, straining and bending at the waist for the first few days, and sleep with your head raised on an extra pillow.
• Do not fly or dive without asking first. Cabin descent and any depth change alter sinus pressure against the same wall.

Ask about decongestants and nasal sprays rather than starting them on your own. They are frequently part of the plan for a known opening, because reducing sinus congestion lowers the pressure sitting on the repair, but the choice of drug interacts with blood pressure, with cardiac history and with other medicines you may have been given for this surgery. It is a short question with a specific answer, and it belongs to the person who operated.

Openings at the smaller end, commonly described in the surgical literature as around 2 millimetres or less, frequently close without any operation, because a stable blood clot in the socket is enough scaffolding for the tissue to seal across. The conditions are specific: the clot has to stay, the sinus has to stay uninfected, and the pressure rules above have to be followed properly for weeks rather than days. That is why the instructions carry more weight than the size does.

A conservative plan for a small opening usually looks like this. The socket is left undisturbed rather than irrigated or packed. A collagen plug or a suture may be placed to hold the clot. Sinus precautions are given in writing and are meant literally. Antibiotics and often a decongestant are prescribed to keep the sinus from becoming the thing that stops the closure. Then you are seen again, generally inside a week and again after that, because whether the opening is closing is a question that gets answered by looking, not by how you feel.

The honest counterweight to all of that: a plan of watching and waiting is only reasonable when someone is actually watching. If you were not given a follow-up date, or if you cannot reach the practice, that plan has quietly become no plan. Say so plainly when you call, and if you cannot get through and the symptoms are worsening — spreading swelling, fever, worsening one-sided pain, discharge — you need to be seen somewhere rather than waiting for a callback.

Larger openings are closed surgically, by moving healthy tissue over the defect and sewing it down so the mouth and sinus are separated by living tissue with its own blood supply. The commonest method takes a flap of gum and cheek lining from beside the socket, releases it so it can travel without tension, and sutures it across. It is a short operation done under local anaesthetic, sometimes with sedation or general anaesthesia depending on the case and on you.

The technical points that decide whether a closure holds are tension and blood supply. A flap stretched to reach will pull apart within days, so the surgeon deliberately releases the tissue beforehand so that it lies flat with no pull on the stitch line. Sharp bone edges around the socket rim are smoothed, because a rim left proud tears the flap from underneath. And the stitch line is positioned to sit over solid bone rather than directly over the hole, so that the repair is supported rather than suspended across a gap.

Where a buccal flap is not suitable — a very large defect, a previous failed closure, a fistula with a well-established lining — other reconstructions exist, including a palatal flap rotated across from the roof of the mouth and, less commonly, a buccal fat pad brought down from behind the cheek. Which one applies is a judgement made by the operating surgeon with the tissue in front of them, and it is a reasonable thing to ask about before consenting.

If the sinus is already infected, the sequence changes. Sewing a healthy flap over an infected sinus tends to fail, because the infection continues to work against the repair from above. In that situation the sinus is usually treated first, with antibiotics and sometimes with drainage, and the definitive closure follows once it has settled. Being told the repair is being delayed is not a delay in your care. It is the reason the repair is likely to work.

Afterwards, the same pressure rules apply and they apply harder, because now there is a stitch line to protect rather than a clot. Expect two to three weeks of strict sinus precautions, a soft diet, no straws, no smoking or vaping, no nose-blowing, and a review appointment to check the closure. Swelling and bruising of the cheek and sometimes the eyelid are ordinary after a flap procedure. Numbness of the cheek skin or the gum near the flap can occur and usually settles.

Go to an emergency department, rather than waiting for a callback, if you have difficulty breathing or swallowing, swelling that is closing your eye or spreading down your neck, a fever with worsening one-sided facial swelling, a sudden change in vision, or bleeding you cannot control with steady pressure. Those are not sinus-opening problems specifically. They are problems that outrank one, and they are assessed in a hospital.

Short of that, an opening into the sinus is a same-day phone call rather than an emergency. What makes it urgent in a different sense is time, not danger: the window in which it is a communication rather than a lined fistula is measured in weeks, and the treatment on the far side of that window is bigger than the treatment on this side. Waiting to see whether it settles is the one strategy that reliably makes it worse.

When you call, be concrete. Say which tooth was removed and on what date, exactly what you noticed and when it started, whether liquid has passed into your nose and how many times, whether your voice has changed, whether you have blown your nose or used a straw since the surgery, whether you have a fever, and what medicines you have been given. Those answers determine whether you are seen today or tomorrow, and vague answers tend to produce vague appointments.

Most upper third molar removals do not produce an opening into the sinus, and the majority of people reading this after an upper extraction do not have one. The complication is associated with particular anatomy — roots that sit against or within the sinus floor, a heavily pneumatised sinus, roots that are widely splayed — and with removals that were difficult rather than routine. Erupted, straightforward upper teeth are far less often involved.

It also does not apply to lower wisdom teeth at all. There is no sinus above a lower third molar, and the risks specific to the lower jaw are different ones entirely, involving nerves rather than air spaces. If your surgery was on the lower jaw, a symptom in your nose is coming from somewhere else and still deserves a call, but not for this reason.

There are people for whom the conservative path is a worse bet, and it is fair to ask whether you are one of them. Uncontrolled diabetes, current smoking, chronic sinus disease, immune suppression and drugs that impair bone healing all reduce the chance that a small opening simply seals, and all of them are things the surgeon should know about before a wait-and-see plan is chosen rather than after it fails. If any apply to you, say so at the first appointment rather than assuming it is already on file.

One thing this page deliberately does not do is help you decide whether you have an opening. That is a decision made by someone looking at the socket, sometimes with an image, sometimes with a gentle test performed by a clinician who knows how much force is safe. Reading a description that matches your symptoms is a reason to call. It is not a diagnosis, and treating it as one is how a two-week window gets spent.

The practice is out of network with every carrier and operates on a cash basis, so nothing here depends on what a plan will or will not do. That is worth saying because it removes one common reason for hesitating over a post-operative call. The reason to pick up the phone is that the problem is smaller today than it will be next month.