Clinical management of a mandibular first molar with supernumerary distal root (radix entomolaris)

Radix entomolares, a supernumerary root on a mandibular molar, located distolingually, is an anatomical variation of the mandibular first molar. This variation requires special care in order to maintain a high success rate of root canal treatment. This paper describes the procedure for treatment of a mandibular first molar with three roots (one mesial and two distal) and four canals (two mesial and one in each distobuccal and distolingual root). This case report reveals the importance of anatomical knowledge of root canals and preoperative radiographs.