Causes of subcutaneous emphysema following dental procedures: a systematic review of cases 1993-2020.

Objectives Causes of subcutaneous emphysema (SE) following dental treatment have changed with new operative techniques and equipment. This review demonstrates the frequency and aetiology of SE to inform prevention strategies for reducing SE occurrences.Methods A systematic search of Medline, Embase and PubMed databases identified 135 cases of SE which met inclusion criteria after independent review by two authors. Trends in frequency and causes of SE were displayed graphically and significant differences in frequency of SE by time period, site and hospital stay were analysed using t-tests.Results Dental extractions often preceded development of SE (54% of cases), commonly surgical extractions. Treatment of posterior mandibular teeth most often resulted in development of SE. Most cases were iatrogenic, with 51% resulting from an air-driven handpiece and 9% from air syringes. Factors such as nose blowing accounted for 10%. There was a significant (p <0.05) increase in cases over time. Mandibular teeth had increased hospital stay time compared to maxillary teeth (p <0.01).Conclusion Increased risks of SE were identified following use of air-driven handpieces during dental extractions and when treating lower molar teeth. Use of air-driven handpieces should be avoided during dental extractions to reduce risks and subsequent morbidity that results from SE.