Figure 1.

(a) Mandibular bilateral first molars with two roots and four canals. (b) Mandibular left first molar with two roots, right first molar with three roots. (c) Bilateral mandibular first molars with five canals and three roots. (d) Mandibular bilateral first molars with two roots and four canals. (e) Mandibular right first molars with three roots and four canals, mandibular right second molar with three roots and three canals, and left second molar with one root and one canal. (f) Mandibular right first molars with two roots and two canals and left first molars with three roots and three canals