What is a parulis?

A parulis (also called a gum boil) is a raised gingival lesion that represents the oral opening (stoma) of a sinus tract draining purulent material from a periapical abscess or other deep odontogenic infection. It appears as a soft, fluctuant papule on the attached or alveolar mucosa. The sinus tract can be traced with a gutta-percha cone to identify the source tooth on radiograph. A parulis indicates pulpal necrosis with a chronic periapical abscess as the source.