Table 1.

Vertucci in 1974 classified the canal configuration of mandibular incisors into four types.

Type	Description
Type I	Single canal is present from the pulp chamber to the apex
Type II	Two separate canal leaves the pulp chamber, but join short of the apex to form one canal
Type III	One canal leaves the pulp chamber, but it divides into two within the body of the root, the canals merge again to exist as one canal
Type IV	Two separate and distinct canals are present from the pulp chamber to apex