is an inflammatory reaction to pulpal infection and necrosis characterized by gradual onset, little
or no discomfort and an intermittent discharge of pus through an associated sinus tract. Radiographically, there are typically
signs of osseous destruction such as a radiolucency. To identify the source of a draining sinus tract when present, a guttapercha
cone is carefully placed through the stoma or opening until it stops and a radiograph is t