Sinus tracts are paths of drainage for abscesses and can occur both intraorally and extraorally. It is a fact that sinus tracts can heal with proper endodontic therapy. However, there are those types that are persistent and will not respond to any treatment. In these perplexing cases, it may be necessary to elevate a surgical flap to unveil the real etiologic factor. In this article, a case is presented in which 2 persistent and nonhealing sinus tracts were observed around the maxillary left incisor area of a 53-year-old female patient. A difficult cast post-and-core removal had been accomplished to the compromised tooth 1 year previously. A surgical flap had to be reflected, and the cause of the persistent inflammation was determined to be 2 separate root perforations. The granulation tissue was removed, the perforations were sealed with mineral trioxide aggregate, and bone graft was packed in the resorptive bone areas. The symptoms subsided by the time of the 2-week recall. No complaints were noted from the patient during the 4-month follow-up period. This case is a good example that demonstrates the possible complications of post preparation and the necessity of explorative surgery for unveiling the etiologic factor of persistent sinus tract formation. Schlagwörter: post and core, root canal therapy, root perforation, sinus tract