Root canal morphology of the human mandibular first molar

Abstract

Forty-five plastic casts of the root canals of extracted human mandibular first molars were fabricated and studied. In approximately one third of the teeth, there were four root canals. When a root contained two root canals, they either remained two distinct canals with separate apical foramina, united to form a common apical foramen, or communicated with each other partially or completely by transverse anastomoses. The frequency of these ramifications has been determined.