In this article, we found the dentigerous cyst due to the impacted supernumerary tooth. Involved teeth were treated with immediat canal filling and root resection technique. The cystic walls and its contents were marsupialized and perfectly enucleated with surgical techniques. After the operations, no clinical signs and symptoms were found, Radiographic findings after I months of the operations reveal the decrease of the radiolucency on the surgical field. The author thinks that it indicate the formation of the osteoid tissue.