The causes of subcutaneous emphysema of relevance to dental practitioners?

Data sources An electronic search was conducted using EMBASE, LILACS, PubMed, SciELO, Scopus, Web of Science, and two grey literature data sources. All issues of nine dentistry journals and relevant chapters in four endodontic textbooks were manually searched. Study selection Abstracts of all the studies that were identified during the electronic and manual searches were obtained and screened independently by two reviewers in order to select clinical studies, case series, or case reports describing subcutaneous emphysema that occurred in adult patients during or immediately after root canal treatment. Data extraction and synthesis Predetermined data were extracted from each study independently by two reviewers and organised into data tables. All disagreements were resolved through discussion with a third reviewer. The data obtained were combined through a narrative synthesis. Results Following full-text evaluation according to the inclusion criteria, 51 articles that described 65 cases of subcutaneous emphysema were included. There were 36 case reports and 15 case series. The condition was mainly reported in female patients and maxillary teeth. While the age of the patients ranged from 18 to 63 years, this demographic information was missing from a few studies. Details on the involved tooth and diagnosis were also missing from several articles. In most of the cases, subcutaneous emphysema developed during initial root canal treatment. The diagnosis was mainly based on intraoral, plain facial, neck, or chest radiographs, while computed tomography (CT) scans were obtained in fewer cases. The majority of the patients were referred to a different practice, a hospital or university clinic for the management of the condition by more specialised healthcare practitioners. In addition to drying root canals using air pressure, irrigation with hydrogen peroxide, and the air-water spray produced by handpieces, it was reported that laser-produced spray and ozone gas infiltration may also be the culprits of subcutaneous emphysema. The signs and symptoms resolve within 17 days. Its management mostly remains empirical and involves the use of antibiotics, analgesics, local application of cold or hot compresses, or administration of oxygen and hospitalisation, among other methods. Conclusions The systematic review showed that subcutaneous emphysema can occur during both surgical and nonsurgical endodontic treatment. Air streams or air-water sprays should not be directed toward the root canals or areas with mucosal discontinuity. None of the management approaches were clearly associated with a faster recovery. The review asked for developing guidelines in order to avoid unnecessary or potentially harmful interventions.