428 Int J Emerg Med (2010) 3:427–429 Fig. 1 Examination revealed a swollen left half of the patient's face Fig. 3 CXR flow supplemental oxygen via a reservoir bag. He was also treated with antibiotics (Co-Amoxiclav 625 mg three times a day for 7 days). No antihistamines, adrenaline or corticosteroids were used in his management. The patient made an uneventful recovery, his facial swelling subsided, and he was discharged home around 14 h after his initial presentation to the Emergency Department. Subcutaneous emphysema (SCE) is a well-documented but little known complication of restorative dentistry particularly when using an air turbine drill [1, 2]. SCE has occurred following root canal or periodontal treatment, dental extraction and dental implants as such procedures are likely to disrupt the dentoalveolar membrane [3]. The use of hydrogen peroxide has also been implicated in the development of SCE [4]. In our case, hydrogen peroxide was not used. Due to the action of pneumatic dental drills, which is driven by compressed air, air can be forced into the subcutaneous tissues of the face through the various Fig. 2 Facial views fascial planes. This is usually a local effect, but air can track into deeper structures resulting even in a pneumomediasti- num [5]. However, there have been reports of airway compromise [6] and even death from air embolism [7] secondary to subcutaneous emphysema following endodon- tic procedures. Treatment is usually supportive as the subcutaneous emphysema resolves within days. An antibi- otic was used in our case as air driven into the subcutaneous tissue would likely carry some oral flora with it that could potentially lead to soft tissue infection [8] including mediastinitis [9]. We used Co-Amoxiclav in line with our hospital antibiotic guideline policy, which pro- vides good cover against oral flora. As our patient had an important meeting to attend the next morning, we provided the patient with supplemental oxygen so as to speed the resolution of the subcutaneous emphysema. There has been no reference in the literature except of case reports describing the use of high-flow oxygen in the management of SCE [10, 11]. However, extrapolating data from the studies using high-flow oxygen in the management of pneumothorax [12], we used it on our patient with dramatic success. The theory behind the use of high flow oxygen is that nitrogen is the largest component of the atmosphere and is not metabolized. Increasing the partial pressure of oxygen in the inspired air will alter the partial pressure gradient of nitrogen in the subcutaneous tissues, which helps increase the rate of resorbption of the subcutaneous emphysema by up to six fold if 100% humidified oxygen is inspired [13]. Use of a rubber dam, vented high speed devices or using sonic/ultrasonic hand drills and avoiding hydrogen peroxide are some of the techniques that have been used to prevent the development of SCE during endodontic procedures [14].