Key points in brief
- Oroantral communication is an opening between an upper tooth's socket and the sinus. If fluid enters your nose when you drink, call the practice the same day, even without pain.
- A very small, fresh opening often closes under the clot if the sinus is healthy. Larger or older ones are protected or closed surgically. Size cannot be judged at home.
- Call the same day if your nose bleeds on the extraction side or you notice air passing into your nose, for example when speaking. Do not test the wound yourself.
- Until the dentist allows it, do not blow your nose or use a straw, and sneeze with your mouth open. With a fever or worsening cheek swelling, see a dentist the same day, even out of hours.
- Swelling that closes your eye, pain when you move the eye or problems with your vision mean you should go straight to A&E (the hospital emergency department).
Consult your case with an expert and get your treatment plan
How an oroantral communication forms after tooth extraction
When an upper back tooth is removed, an opening into the maxillary sinus may be left behind. Dentists call it an oroantral communication, and in everyday speech people talk about a hole into the sinus or a sinus perforation. The maxillary sinus is an air-filled space in the bone of the upper jaw that lies just above the roots of the upper back teeth. The opening forms in the floor of the socket, the place where the root sat.
Saliva, food debris and bacteria from the mouth can get into the sinus through such an opening, which makes inflammation of the sinus (sinusitis) more likely. That is why the opening is not left without care, even when it does not hurt. If a fresh communication needs to be closed, dentists try to do this within 1–2 days, before inflammation develops in the sinus.
Saliva, food debris and bacteria from the mouth can get into the sinus through such an opening, which makes inflammation of the sinus (sinusitis) more likely. That is why the opening is not left without care, even when it does not hurt. If a fresh communication needs to be closed, dentists try to do this within 1–2 days, before inflammation develops in the sinus.
The dentist often spots the communication during the procedure and protects it straight away. Sometimes, however, the first symptoms appear only at home - for example, when you start drinking once the anaesthetic has worn off. If the opening does not close, its channel gradually becomes lined with mucous membrane. Such an established channel is an oroantral fistula, which usually no longer closes on its own.
Not every change in the wound points to a connection to the sinus. A white coating in the first few days is usually fibrin, part of a normally healing blood clot after tooth extraction, and not a sign of a communication.
What not to do with the wound until your appointment
If you suspect an oroantral communication after tooth extraction, call the practice that same day, and until your appointment protect the clot in the socket and avoid raising the pressure in your nose.
- Do not check for yourself whether air passes through the wound. Do not blow with your nose pinched shut, and do not touch the socket with your finger or tongue.
- Do not blow your nose. Wipe away any discharge gently without blocking your nostrils, and sneeze with your mouth open.
- Do not drink through a straw, do not smoke and do not rinse your mouth vigorously.
- Drink in small sips and chew soft food on the other side. Leave any stitches or dressing alone if the dentist has placed them.
- Do not start an antibiotic or nasal drops you have left over at home on your own initiative.
Write down when the symptom first appeared and what you were doing at the time, for example drinking. This helps the dentist judge how fresh the opening is.
Will a hole into the sinus after tooth extraction close on its own?
A very small, fresh opening often closes on its own under the blood clot. If the opening is larger or older, the dentist protects it or closes it surgically.
| Approach | When it is chosen | What it means for you |
|---|---|---|
| Observation | a very small, fresh opening, no inflammation in the sinus | the clot stays in place, you follow the instructions, and at a check-up the dentist checks whether the opening has closed |
| Protecting the clot | a medium-sized, fresh opening | the dentist stitches the edges of the wound or places a dressing, or a material prepared from your own blood taken during the visit, which supports the clot |
| Surgical closure | a large opening, an established fistula, or a fragment of root in the sinus | the surgeon, usually with a local anaesthetic, covers the opening with a flap, that is, a piece of the lining of the mouth moved from the cheek or the palate and stitched over the wound |
The dentist assesses the size of the opening at the practice, sometimes with the help of an X-ray, because it cannot be determined at home. Closure is sometimes possible at the same visit at which the dentist diagnoses the communication. That is why, if you notice a symptom after the extraction, you should call the practice that same day.
In studies, medium-sized, fresh openings protected with a dressing or with material from the patient's own blood usually closed within a month. Closing the opening with a flap succeeds at the first attempt in roughly 9 out of 10 patients. If it does not, the dentist usually treats the sinus first and then closes the opening again.
Closing the communication with a flap belongs - like the extraction itself - to dental surgery. If you are planning an implant where the tooth was removed, dentists usually wait from a few months to a year after the opening has been closed. Sometimes the bone also needs to be rebuilt at that stage, for example by raising the sinus floor, a procedure that increases the amount of bone below the sinus.
Symptoms of a connection to the sinus and when to call the practice
The most typical symptom of a fresh communication is fluid, and sometimes bits of food, passing from the mouth into the nose on the side of the removed tooth when you drink or eat. Symptoms can be slight: a few drops of water in your nose when you drink, or a whistle of air when you speak. Having no symptoms on the day of the extraction does not rule out a communication, so treat symptoms that appear over the following days the same way as those noticed straight away.
- Mild swelling of the cheek and slight bleeding from the wound in the first 24 hours after an extraction are common. Blood from the nose on the side of the extraction and fluid in the nose are not a normal effect of having a tooth out.
- Call the practice that same day, even if nothing hurts, if fluid or bits of food pass from your mouth into your nose, or air passes between your mouth and nose. The same applies to blood from the nose on the side of the extraction and to a voice that sounds more nasal than usual. Also call if, a few days after the communication has been closed, fluid passes into your nose again, because the opening may not have healed. If the practice is closed, go to an emergency dental service.
- After a few days or weeks, symptoms of a fistula or of sinusitis may appear. They include an unpleasant taste in your mouth or bad breath, thick discharge from one side of the nose, a blocked nose on the side of the extraction, and pain or pressure in the cheek below the eye. With symptoms like these, call the practice the same day, without waiting for your scheduled check-up.
- If you develop a fever, or the swelling of your cheek is growing, see a dentist the same day, at an emergency dental service if necessary. If the swelling spreads to the area around the eye or closes your eye, moving the eye hurts, or you see double or your vision gets worse, go straight to A&E.
How the dentist checks whether the wound connects to the sinus
First, the dentist looks at the socket. Then, gently and without pressing, they check the floor of the wound with a blunt instrument. They may also carry out a short test that involves blowing, which is done once, gently and only under a dentist's supervision. Do not repeat it at home.
If an X-ray is needed, a panoramic X-ray, which shows all the teeth at once, is usually enough. It shows whether a fragment of root has been left in the sinus. When the dentist needs to assess the bone loss or the condition of the sinus in detail, they order cone-beam CT (CBCT), a three-dimensional scan that involves a higher dose of radiation.
If the opening has been there for longer, the dentist also checks whether inflammation has developed in the sinus. The inflammation usually has to be treated before the dentist closes the opening, because closure over an inflamed sinus fails more often. The dentist treats it with medicines and often also rinses the sinus through the opening. Sometimes they ask an ear, nose and throat (ENT) specialist for an opinion.
Bring the X-ray taken before the extraction to the appointment, if you have it. Tell the dentist when the tooth was removed and whether the wound has already been stitched or protected.
Instructions that protect the clot and the sinus
Once the dentist has diagnosed a communication, whether it is being observed or has been closed, you usually protect the clot and avoid raising the pressure in your nose for 2–3 weeks. The general tooth extraction aftercare still applies, but the waiting times given after a routine extraction - for example before flying - are too short in this case. Pressure in the nose is passed on to the sinus and from there to the clot or the stitches, so these rules apply:
- do not blow your nose, and sneeze with your mouth open;
- avoid exertion that makes you strain with your mouth closed, for example lifting heavy things;
- do not drink through a straw and do not smoke;
- eat soft food on the other side, and brush your teeth gently, away from the wound.
The dentist may recommend decongestant nasal drops for a few days and rinsing your mouth with a chlorhexidine mouthwash. The drops reduce swelling inside the nose, which is meant to make it easier for the sinus to clear and for you to breathe, and then it is easier to manage without blowing your nose. On their own, they do not replace the other instructions. If you have a runny nose or an allergy, tell the dentist, because it is then harder to avoid sneezing and blowing your nose.
The dentist decides about an antibiotic case by case. Complications occurred less often in people who were given one after the opening was closed, but it is not known whether every patient needs it.
The dentist decides at a check-up when you can stop following these instructions. The first check-up usually takes place after one or two weeks.
What to do if fluid passes into your nose after an upper tooth is removed
Call the practice that same day, and until your appointment do not blow your nose or test the wound by blowing. A connection to the sinus can usually be closed, and early diagnosis makes this easier. After the visit, follow the instructions until the dentist tells you that you can stop.
Frequently asked questions
Does fluid coming out of your nose after a tooth extraction always mean a connection to the sinus?
Not always, but after the removal of an upper back tooth it is a typical symptom of a connection to the sinus and needs to be checked that same day. Discharge that is not related to drinking can be an ordinary runny nose, but thick discharge from one side of the nose may mean sinusitis, and then you should call the practice the same day. Only an examination at the practice gives certainty, because the wound cannot be checked safely at home.
Can you blow your nose if you have a connection to the sinus?
No. Blowing your nose sharply raises the pressure in the nose and in the sinus, and this can disturb the clot or the stitches. Wipe a runny nose gently, without blocking your nostrils. If your nose is badly blocked, tell the dentist, because they may recommend drops. Sneeze with your mouth open, and never test the wound by blowing with your nose pinched shut.
When can sinusitis appear after a tooth extraction?
If the opening does not close, sinusitis may develop within a few days or weeks, and the risk grows over time. After the opening has been closed, sinusitis occurs in a small proportion of patients. If complications do appear after closure, the dentist often detects them within the first week. So come to the check-up after one or two weeks, even if you feel well.
Is a fistula after a tooth extraction the same as a sinus tract on the gum?
No. An oroantral fistula is an established channel between the mouth and the maxillary sinus, through which fluid and air pass into the nose. A dental sinus tract on the gum is an outlet for pus from an infected tooth, usually in the form of a small pimple. Despite the word “sinus” in its name, it is not connected with the maxillary sinus. These are two different problems, treated in different ways.
What is healing like in the first week after the communication is closed?
For the first few days the cheek may be swollen, and the pain eases. A flap taken from the cheek may make the space between the cheek and the gum shallower, which may make wearing a denture more difficult. If the pain gets worse, you develop a fever or fluid passes into your nose again, see a dentist the same day, at an emergency dental service if necessary. If the swelling closes your eye, moving the eye hurts or your vision is disturbed, go straight to A&E.
How long should you avoid blowing your nose and flying?
The rule against blowing your nose usually applies for 2–3 weeks. Flying, diving and playing a wind instrument are put off at least until the check-up at which the dentist confirms that the opening has closed. During these activities, the pressure in the sinus changes sharply. The exact timing depends on the size of the opening and how healing is going, so the dentist sets it.
Read more:
- Dental Surgery in Warsaw Wola
- Tooth extraction aftercare: washing your hair, sleeping, work, sick leave and smoking
- Blood clot after tooth extraction — what a normally healing socket looks like
- Bone augmentation before an implant — when is it necessary and what types are available?
- Wisdom teeth — remove or keep? A comprehensive extraction guide
Content and liability disclaimer
This article is informational and educational in nature and does not constitute medical advice, a diagnosis or a therapeutic recommendation — it does not replace a consultation with a specialist. If you are experiencing symptoms, have doubts or are facing a decision about treatment, consult a dentist. The methods described and the data cited are general in nature. The results of scientific studies relate to populations, not to an individual patient. The course and outcome of therapy depend on the individual clinical situation and may vary between patients. No information contained in this article constitutes a guarantee of result. The content has been prepared with due care, based on publicly available medical knowledge and the scientific publications indicated in the Sources section. We do not advise taking or refraining from any health-related action solely on the basis of the content of this article, without prior consultation with a doctor.
Sources
Source 1
Links https://doi.org/10.1007/s00784-026-07189-9 │ https://pubmed.ncbi.nlm.nih.gov/42814174/ │ https://pmc.ncbi.nlm.nih.gov/articles/PMC13627183/
Description Bakacak MM, Ho JPTF, van der Meij EH, Schreuder WH, Lodders JN. „The effect of postoperative antibiotics in reducing complications following primary surgical closure of oroantral communications secondary to tooth extraction: a retrospective multicenter study.” Clinical Oral Investigations. 2026;30(10):494.
Source 2
Links https://doi.org/10.1007/s00784-025-06335-z │ https://pubmed.ncbi.nlm.nih.gov/40266377/ │ https://pmc.ncbi.nlm.nih.gov/articles/PMC12018612/
Description Bakacak MM, Hoogeveen RC, Berkhout WER, Van Cann EM. „Using panoramic radiographs to assess the probability of causing oroantral communication following tooth removal. A retrospective cross-sectional study.” Clinical Oral Investigations. 2025;29(5):263.
Source 3
Links https://doi.org/10.1007/s00784-022-04846-7 │ https://pubmed.ncbi.nlm.nih.gov/36607489/ │ https://pmc.ncbi.nlm.nih.gov/articles/PMC10264294/
Description Hunger S, Krennmair S, Krennmair G, Otto S, Postl L, Nadalini DM. „Platelet-rich fibrin vs. buccal advancement flap for closure of oroantral communications: a prospective clinical study.” Clinical Oral Investigations. 2023;27(6):2713-2724.
Source 4
Links https://doi.org/10.1007/s00784-024-06000-x │ https://pubmed.ncbi.nlm.nih.gov/39443353/ │ https://pmc.ncbi.nlm.nih.gov/articles/PMC11499406/
Description Jurásek A, Farkas N, Frank D, Kolarovszki B, Sándor B, Radácsi A, Szántó I, Katona K. „Evaluation of clinical and radiographic warning signs for prediction of oroantral communication following tooth extractions.” Clinical Oral Investigations. 2024;28(11):609.
Source 5
Links https://doi.org/10.1016/j.joms.2023.09.006 │ https://pubmed.ncbi.nlm.nih.gov/37802130/
Description Kaba YN, Soylu E, Demirbas AE, Kilavuz MS. „Is an Attachable Oral Wound Dressing Effective at Closing an Acute Oroantral Communication?” Journal of Oral and Maxillofacial Surgery. 2023;81(12):1557-1568.
Source 6
Links https://doi.org/10.1016/j.jds.2020.08.001 │ https://pubmed.ncbi.nlm.nih.gov/33384837/ │ https://pmc.ncbi.nlm.nih.gov/articles/PMC7770314/
Description Psillas G, Papaioannou D, Petsali S, Dimas GG, Constantinidis J. „Odontogenic maxillary sinusitis: A comprehensive review.” Journal of Dental Sciences. 2021;16(1):474-481.
Source 7
Links https://doi.org/10.1186/s12903-024-04217-6 │ https://pubmed.ncbi.nlm.nih.gov/38600501/ │ https://pmc.ncbi.nlm.nih.gov/articles/PMC11007963/
Description Ibrahim MT, Gharieb EA, Sheta MS. „A pedicled buccal periosteal flap for the closure of oro-antral fistula.” BMC Oral Health. 2024;24(1):440.
Source 8
Links https://doi.org/10.1186/s12903-025-05958-8 │ https://pubmed.ncbi.nlm.nih.gov/40301851/ │ https://pmc.ncbi.nlm.nih.gov/articles/PMC12039167/
Description Kheiri L, Amid R, Kadkhodazadeh M, Kheiri A. „What are the outcomes of dental implant placement in sites with oroantral communication using different treatment approaches?: a systematic review.” BMC Oral Health. 2025;25(1):652.