Relationship between Root Apices and the Mandibular Canal: A Cone-beam Computed Tomographic Comparison of 3 Populations.

This study aimed to investigate the difference in the location of the inferior alveolar nerve (IAN) in relation to the apices of mandibular molars in 3 different populations using cone-beam computed tomographic (CBCT) imaging and to assess the proportion of teeth in close proximity (a distance of 1 mm or less) to the IAN.Random CBCT images (N = 1224, Israel = 408, South Korea = 416, and India = 400) were examined. The shortest distance to the mandibular canal was measured by imaging software.The mean distance was 4.81 ± 2.15 mm. The mean distances for Israel, South Korea, and India were 4.60 ± 2.37 mm, 5.45 ± 2.13 mm, and 4.35 ± 1.76 mm, respectively. The distance in samples obtained from South Korea was significantly larger than the distance in samples obtained from Israel and India (P < .05). Samples from Israel exhibited close proximity in 6.6% of samples versus 3% in samples from India and 0.7% of samples from South Korea, a statistically significant difference (P < .05).Although variation in tooth morphology in different populations was widely researched, the variation in the location of the IAN in relation to tooth apices of different populations was not addressed in the literature. Our study reveals that a difference in the distance of the apices to the IAN exists between populations as well as a difference in the proportion of teeth in close proximity to the IAN.