In recent years, reports of subcutaneous and mediastinal emphysema resulting from the use of dental lasers have increased. This paper reports a case of mediastinal emphysema caused by CO2 laser irradiation. The patient was a 76-year-old man who underwent CO2 laser irradiation to treat a gingival abscess between the upper right canine and the first premolar at a dental clinic. During the treatment, his right cheek and right eyelid suddenly became swollen. Subsequently, the swelling spread from the right submandibular region to the neck and he was referred to our hospital. A CT examination revealed subcutaneous emphysema from the right temporal region to the bilateral cervical region, as well as mediastinal emphysema extending to the aortic arch. The patient was hospitalized and received anti-inflammatory therapy. The emphysema had nearly disappeared by the 7th day, and he was discharged on the 8th day. We need to recognize the possibility of mediastinal emphysema caused by CO2 laser irradiation and to know how to treat it appropriately.
