Iatrogenic subcutaneous cervicofacial emphysema with pneumomediastinum after class V restoration.

Subcutaneous facial emphysema after dental treatment is an uncommon complication caused by the invasion of high-pressure air; in severe cases, it can spread to the neck, mediastinum, and thorax, resulting in cervical emphysema, pneumomediastinum, and pneumothorax. The present case showed subcutaneous cervicofacial emphysema with pneumomediastinum after class V restoration. The patient was fully recovered after eight days of conservative treatment. The cause of this case was the penetration of high-pressure air through the gingival sulcus, which had a weakened gingival attachment. This case indicated that dentists should be careful to prevent subcutaneous emphysema during common dental treatments using a high-speed hand piece and gingival retraction cord.