Comparison of mesiodistal root angulation of teeth by conventional panoramic and cone beam computed tomography images – A cross-sectional study

Introduction: Accurate bracket positioning is required for proper root parallelism and for stable orthodontic treatment outcomes. This study aimed to determine the difference in mesiodistal root angulation of teeth measured on three radiographic images. Material and methods: A cross-sectional study was conducted using orthopantomogram (OPG), panoramic images of cone beam computed tomography (Pan-CBCT) and cone beam computed tomography (CBCT). An occlusal plane was constructed in OPG and Pan-CBCT for angular measurements. The axial and sagittal views were used for assessing the mesiodistal root angulation on CBCT. Mesiodistal root angulation differences among three radiographs were assessed using the Kruskal-Wallis test. Mann-Whitney U test was applied for pairwise comparison and multinomial logistic regression was used to determine the association of sexual dimorphism with the direction of root angulation. Results: On comparing the mesiodistal root angulation in degrees (DE) among all three groups, upper right (UR2) and left lateral incisors (UL2) were found to be statistically significant with P = 0.033 and P = 0.050 respectively. On pair-wise comparison, we found a statistically significant difference for upper right lateral incisor (UR2) between OPG and Pan-CBCT (P = 0.045). Upper left lateral (UL2) (P = 0.024) was significant in OPG and Pan-CBCT while upper left first molar (UL6) (P = 0.043) in OPG and CBCT group. On comparing the sexual dimorphism in the direction of root angulation, females showed a greater tendency of mesial root angulation (5.62) times for upper right second premolar (UR5) as compared to males. Conclusions: There were no significant difference in mesiodistal root angulation between panoramic CBCT and CBCT images. The angulation of the upper lateral incisors was found to be significant between OPG and panoramic CBCT images, whereas the angulation of the upper right lateral incisors and left first molars was significant between OPG and CBCT images. In terms on sexual dimorphism, females showed greater mesial angulation of teeth than males.