LAUSR

BACKGROUND Subcutaneous emphysema is an infrequent mishap during root canal treatment which, in rare cases, can lead to severe complications. AIM To systematically review the literature on the factors affecting the development of subcutaneous emphysema during root canal treatment, and on its management. DATA SOURCES An electronic search was conducted in EMBASE (1947-2018), LILACS (1982-2018), PubMed (1950-2018), SciELO (1997-2018), Scopus (1970-2018), Web of Science (1900-2018), and two grey literature databases. Moreover, all issues of nine journals and four endodontic textbooks were hand-searched. STUDY ELIGIBILITY CRITERIA, PARTICIPANTS, INTERVENTIONS The retrieved studies were screened by two reviewers to select clinical studies, case reports or case series describing subcutaneous emphysema that developed during or immediately after root canal treatment in adult patients. STUDY APPRAISAL AND SYNTHESIS METHODS Included studies were critically appraised according to a custom list of quality requirements. The extracted data were arranged in tables and they were combined through a narrative synthesis. RESULTS The search retrieved 99 unique articles. Thirty six case reports and 15 case series describing 65 cases of subcutaneous emphysema in total were included in this review. The methodological quality was medium. Reported cases of emphysema more often involved females and maxillary teeth. Drying of the root canal system with air under pressure, inadvertent extrusion of hydrogen peroxide through the apical foramen, the air-water spray produced by handpieces or laser devices, and the use of ozone gas were the most commonly suspected causes. Its management involved prescription of antibiotics and NSAIDs/analgesics, local application of ice packs or compresses, and hospitalization. The signs and symptoms resolved completely within 1-17 days. LIMITATIONS Case reports and case series are a low level of evidence. CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS Subcutaneous emphysema can develop during both non-surgical and surgical root canal treatment. Pressurized air streams or air-water sprays should not be directed towards the root canals or areas with mucosal discontinuity. None of the management approaches is clearly related to expedited recovery. Guidelines should be developed in order to avoid unnecessary or potentially harmful interventions. This article is protected by copyright. All rights reserved.