PURPOSE: This study investigated root number and canal configurations,
including morphological variations, of mandibular first molars in a subpopulation of South Africans.
METHODS: Two calibrated examiners retrospectively evaluated 371 mandibular first molars by using high-resolution cone-beam CT images and
the Vertucci classification system with the additions of Sert and Bayirli.
Internal and external configurations were recorded, and correlations of sex
and age with root number and canal configuration were determined with
the chi-square and Fisher exact tests (P < 0.05).
RESULTS: Among mandibular first molars, 0.3% were single-rooted, 98.7%
were two-rooted, and 1% were three-rooted. The most frequent configuration was Vertucci Type IV in mesial roots and Vertucci Type I in distal
roots. Middle mesial canals were found in 20% and middle-distal canals
in 7% of samples. The prevalence of third canals increased in mesial and
distal roots as age increased (P > 0.05). Canal configuration and sex were
not correlated (P > 0.05).
CONCLUSION: Mandibular first molars exhibited diverse anatomic characteristics in this subpopulation. Clinicians should be aware of the possibility
of additional canals in mandibular first molars, as treatment outcomes may
be worse if canals are left untreated.