A classification study on the root canal morphology of the mandibular first premolars in Mongolian and Han populations based on CBCT technology

WANG Junyan; WANG Bin; CHEN Lichun

doi:10.15956/j.cnki.chin.j.conserv.dent.2026.02.006

Abstract：Objective To study the root anatomy,root canal classification and the anatomical relationship between root and mental foramen of mandibular first premolars in Mongolian and Han population by CBCT.Methods A retrospective collection of 100 cases(50 cases each for Mongolian and Han)of CBCT examinations conducted at the Stomatological Hospital of Inner Mongolia Autonomous Region People's Hospital from January to December 2023 due to other dental diseases was made.On the three-dimensional reconstructed images,the following indices were observed and recorded:the number of roots(single root/double roots/fused roots);root canal classification(Vertucci classification);the vertical distance from the root apex to the mental foramen in the sagittal plane.Chi-square test was used to compare the differences in root morphology and root canal classification between the two ethnic groups,independent sample t-test was used to analyze the differences in the distance from the root apex to the mental foramen between the two ethnic groups,and Pearson correlation analysis was used to evaluate the positional correlation between the tooth position and the mental foramen.Results Root morphology:80%of Mongolians had single roots,16%had double roots,and 4%had fused roots;for Han people,the figures were 90%,4%,and 6%,respectively.There was no statistically significant difference between the groups(χ²=4.094,P=0.129).Root canal classification:In Mongolians,types Ⅰ(54%),Ⅴ(18%),and Ⅳ(16%)were predominant;in Han people,type Ⅰ(40%)was predominant.There was a significant difference in distribution between the two ethnic groups(χ²=14.23,P=0.007).Relationship with the mental foramen:There was a statistically significant difference in the distance from the root apex to the mental foramen between the two ethnic groups(P<0.05).The distance from the root apex to the mental foramen of the mandibular first premolars in Mongolians was farther than that in Han people(6.112±1.971)mm vs(5.471±1.066)mm,(t=2.002,P=0.049).Conclusion There are significant ethnic differences in the root canal system of the mandibular first premolars between Mongolians and Han people,and the anatomical relationship between the root and the mental foramen varies by ethnicity.Personalized assessment based on ethnic anatomical characteristics is necessary during root canal treatment or apical surgery.