You are home after a tooth extraction or a filling, and one cheek has suddenly puffed up. When you press on it, the skin feels soft and crackles under your fingertips. That crackling suggests air has been pushed into the tissue under the skin, a problem called subcutaneous emphysema. It is uncommon and usually settles over about a week, but it should be checked the same day, because the air can occasionally track down into the neck and chest.
This article explains how air gets in, how it differs from other swelling after dental work, which signs mean calling 000, and what usually happens next.
The crackle is the main clue
Doctors call the crackling feeling crepitus. In a 2026 scoping review of 129 published cases of swelling caused by air after dental procedures, swelling was reported in 122 people and crepitus in 110. Pain was reported in fewer than half (57), so a swollen cheek that crackles but does not hurt much still needs attention.
The same review lists the other causes a clinician has to rule out: an allergic reaction, angioedema (deep swelling under the skin), a haematoma (a collection of blood, like a deep bruise), infection, ordinary swelling after surgery, and a few rarer conditions. The authors describe sudden swelling during or shortly after dental treatment, particularly with crepitus, as an important diagnostic clue. If there is no crackling and the swelling has built up gradually around a sore tooth, our articles on swelling after a filling and facial swelling from a dental infection are more likely to apply.
How air gets under the skin
Air can enter through an opening in the gum or the inside of the mouth: an extraction socket, a periodontal pocket or the pocket around an implant, a root canal, a small tear in the lining of the mouth, or a surgical wound. From there it can spread through the connected spaces of the face and neck. Air that reaches the deep spaces under the jaw and in the neck can, in some cases, continue into the chest (the mediastinum). Air from the upper jaw can travel towards the eye socket.
Published cases point to a few common sources:
- Air-driven instruments. A systematic review in the British Dental Journal (Jones and colleagues, 2021) collected 135 cases reported between 1993 and 2020. About half (51%) followed use of an air-driven handpiece and 9% followed use of an air syringe. Extractions came before 54% of cases, most often surgical extractions, and treatment of lower back teeth was the most common setting.
- Air polishing and other gum treatment. A 2026 review of 36 cases after periodontal (gum) procedures found that air-powder polishing devices were involved in two thirds of them, followed by dental lasers and air-water syringes.
- Pressure you create after treatment. In the 2021 review, things such as nose blowing accounted for about 10% of cases. An Australian report from Gold Coast University Hospital described an 18-year-old whose cheek swelled progressively over five days after a long but routine removal of an upper wisdom tooth. The cause turned out to be habitual straw use, and the swelling was at first thought to be an infection such as an abscess.
It can also happen when no air-driven tool is used. A 2017 case report in Dental Update described extensive emphysema in the face and neck after surgical removal of a lower molar under local anaesthetic with no air-driven handpiece, and the patient recovered fully. Published reports are case reports, so they show what can happen, not how often it happens.
Call 000 or go to an emergency department if
healthdirect advises emergency medical care if toothache or gum swelling causes problems with breathing, problems with speaking, or swelling around your eye or neck. The 2026 review also lists trouble swallowing, a hoarse or changed voice, chest discomfort, shortness of breath, eye symptoms and any change in alertness as signs that the air may have spread further. Any of these needs urgent medical assessment, not a wait for a dental appointment.
If the swelling is only in your cheek
Contact the dentist who treated you the same day and describe the crackling, when it started and what was done. The review authors advise that sudden swelling with crepitus after dental treatment should prompt immediate assessment.
Until you are seen, avoid things that build up pressure in the mouth or nose. The review authors suggest avoiding forceful nose blowing when there may be an opening between the mouth and the tissues or sinus, and the Gold Coast report links one case to straw use. If an upper back tooth was removed, our article on an opening into the sinus after an upper extraction covers the usual precautions in more detail.
What the dentist or doctor checks
The assessment may include feeling the swollen area for crepitus, reviewing the procedure and instruments used, and checking pulse, breathing, swallowing, voice, chest and eye symptoms. A CT scan is most useful when the swelling goes beyond a small area of the face, or when spread into the neck, chest or eye socket is suspected. The review authors note that case reports do not show that every small, stable swelling needs a scan. In the 2026 review, about three in four patients had at least one CT scan.
Antibiotics were reported in most published cases (82% in the 2026 review). The authors point out that case reports cannot show whether antibiotics, imaging or hospital admission change the outcome, so the plan depends on how far the air has spread and how unwell the person is.
How long it takes to go down
A 2024 systematic review of published case series (Kanaparthi and colleagues) describes air in the face and neck as self-limiting, meaning it usually settles on its own. Among the cases in the 2026 review with a recorded time, complete resolution took a median of 7 days, with the middle half between 5 and 11 days and a range of 0 to 30 days. In the review of gum procedures, the median was 5 days. A small Japanese case series that measured the air on CT found the volume had fallen by more than half within 3 days.
In published cases, most people recovered without lasting effects. Of the 129 patients in the 2026 review, 114 had no persistent problems reported. Serious complications such as a collapsed lung (pneumothorax), airway compromise, air entering a blood vessel and death have been published, but they are rare, and the authors caution that their case counts cannot be read as a measure of risk.
For dentists: reducing the risk and spotting it early
The British Dental Journal review concluded that air-driven handpieces should be avoided during dental extractions, after finding that air-driven handpieces were the most common documented cause (51% of cases), that extractions preceded 54% of cases and that treatment of lower back teeth was most often involved. The 2026 scoping review lists further precautions drawn from recurring case patterns: avoid direct pressurised air near extraction sockets, periodontal or peri-implant defects, root canals with a compromised apical barrier, mucosal tears and fresh surgical wounds, use non-air-driven or appropriately vented systems where feasible, and follow the device instructions for subgingival air polishing. Its authors note these are plausible precautions rather than tested ones.
If a patient's face swells suddenly during or shortly after treatment, the review advises palpating for crepitus, stopping the use of pressurised air if crepitus is present, and checking vital signs and airway, swallowing, voice, chest, eye and neurological symptoms. It advises urgent escalation if symptoms are progressing, the airway is a concern, or there are eye, neurological or chest complications. The review also advises telling patients to avoid forceful nose blowing and other pressure-generating behaviours when a tissue or sinus communication is possible. The Gold Coast authors, whose patient's emphysema followed habitual straw use after a simple extraction, recommended routine post-extraction advice on sinus precautions regardless of how complex the extraction was.
Common questions
Can it appear hours or days after treatment?
Yes. Swelling often appears during treatment or shortly after, but delayed onset has been reported, including a case 10 hours after a lower molar extraction and the five-day build-up linked to straw use in the Gold Coast report.
Is it an allergic reaction to the anaesthetic?
It can look similar, and an allergic reaction is one of the things a clinician considers. Crackling under the skin points towards air rather than allergy. Our article on allergic reactions to dental materials and anaesthetic covers that side in more detail. Any swelling with breathing difficulty needs 000.
Should I press on it to check?
A gentle touch is enough to notice the crackle. Whatever you feel, the swelling should be assessed by a dentist or doctor rather than at home.
Getting it checked
Lumi Dental offers emergency appointments, and we are open Monday to Saturday, Thursday until 9pm, with Sunday by appointment. If you notice a crackling swelling after dental treatment and have none of the emergency signs above, call the practice that treated you, or see our emergency dental care page to arrange an emergency appointment in Melrose Park. If breathing, speaking or swallowing is affected, call 000 first.
Sources
- Kuchler U, Scholter L, Gruber R. Dental procedure-related emphysema: a scoping review of clinical presentation, anatomical distribution, management, and outcomes. Dentistry Journal, 2026. PubMed 42782989
- Jones A and colleagues. Causes of subcutaneous emphysema following dental procedures: a systematic review of cases 1993 to 2020. British Dental Journal, 2021. PubMed 34686817
- Sahin AG, Kurtis MB. Subcutaneous emphysema following periodontal interventions: a comprehensive literature review and clinical considerations. Dentistry Journal, 2026. PubMed 41892771
- Chang VKO, Tsai HH. Patient-induced progressive facial subcutaneous emphysema masquerading as odontogenic abscess. BMJ Case Reports, 2021. PubMed 34162621
- Gowans K, Patel M, Lewis K. Surgical emphysema: a rare complication of a simple surgical dental extraction without the use of an air-driven rotor. Dental Update, 2017. PubMed 29172328
- Shimizu R and colleagues. Subcutaneous emphysema related to dental treatment: a case series. Healthcare, 2022. PubMed 35206904
- Nożewski JB and colleagues. A 39-year-old woman with cervicofacial and mediastinal emphysema 10 hours after an elective lower molar dental extraction. American Journal of Case Reports, 2021. PubMed 34739477
- Kanaparthi K and colleagues. Cervicofacial emphysema: a systematic review. Intractable and Rare Diseases Research, 2024. PubMed 39628623
- Healthdirect Australia. Toothache and gum swelling. healthdirect.gov.au
This article is general information only and is not a substitute for an in-person assessment by a dental professional. If you have difficulty breathing, speaking or swallowing, call 000.
