D41

#41. The mandibular central incisor always has one root, but often (20 %) has two root canals. Usually (75 %), the two canals join before the apical foramen. The canal(s) is very flattened: wide in the bucco-lingual dimension and narrow in the mesio-distal dimension. Only the most apical part of the canal is more round. The long axis of the canal traverses the incisal edge or the labial surface of the crown. Because the access opening is made, for aesthetic reasons, in the lingual surface, there is always a risk that the lingual canal is missed unless it is specifically looked for with a pre-curved file. For the same reason there is a risk of unsymmetrical preparation of the labial side of the root canal. The canal(s) of the lower central incisor is almost always straight unlike in the lower lateral incisor, where the root tip and canal often curve sharply distally.

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