MANDIBULAR FIRST MOLAR

This is often the most heavily restored tooth in the adult dentition and seems to be a frequent candidate for root canal treatment. Generally there are two roots and three canals: two canals in the mesial root and one large oval canal distally. According to Skidmore and Bjorndal, one third of these molars have four canals. Occasionally, three roots are to be found: usually two distal and one mesial (Fig. 10),

rarely one distal and two mesial. Anastomoses occur between the canals and accessory communication with the furcation area is a frequent finding. The mesiobuccal canal tends to exhibit the greatest degree of curvature. The access cavity once again represents the shape of the pulp chamber, enlarged slightly, and flared up on to the mesiobuccal aspect of the occlusal surface to accommodate the angle of instrument approach when working at the back of the mouth.