Concurrent relationship between additional canals of mandibular first molars and maxillary first molars using cone-beam computed tomography

Objective

To investigate the bilateral concurrence and relationships between distolingual (DL) roots and DL canals of the mandibular first molars and second mesiobuccal (MB2) canals of the maxillary first molars using cone-beam computed tomography (CBCT).

Methods

A total of 150 CBCT images showing all mandibular and maxillary first molars were retrospectively investigated in a South Korean subpopulation. The patient age, sex, positions of first molars, and presence of roots and canals were assessed. The frequency, bilateral concurrence of DL roots, DL canals, and MB2 canals, and concurrent relationship of DL roots or DL canals with MB2 canals were investigated. Data were analyzed using Fisher’s exact test and odds ratios from binary logistic regression.

Results

The prevalences of DL roots, DL canals, and MB2 canals were 24.7, 42.7, and 56.0 %, respectively, and showed significant bilateral concurrence. A concurrent relationship between DL roots and MB2 canals was not demonstrated, whereas the presence of a DL canal was significantly correlated with the presence of an MB2 canal on the same side.

Conclusions

The presence of a DL root of the mandibular first molar, a strong ethnic characteristic, could not predict the presence of an MB2 canal of the maxillary first molar. The correlation between DL canals and MB2 canals on the same side and the significant bilateral concurrence, whether present or absent, of DL roots, DL canals, and MB2 canals can aid clinicians in the prediction of additional canals in the first molars.