Abstract：
OBJECTIVE: This study aimed to investigate the relationship between the aspect ratios of mandibular molar roots at the apical 3-mm level and their root canal complexity.
METHODS: This study used micro-CT imaging to analyze 163 two-rooted mandibular molars. The aspect ratios of the roots at the apical 3-mm level were categorized as \"< 2.75\" or \"≥ 2.75\" (mesial) and \"< 1.75\" or \"≥ 1.75\" (distal). A two-dimensional (2D) analysis focused on four apical axial cross-section levels to determine the presence of main and accessory canals and isthmus. Additionally, a three-dimensional (3D) assessment of the apical 4-mm of both roots examined main and accessory canals, apical foramina, apical deltas, and middle mesial canals.
RESULTS: Mesial roots with aspect ratios ≥ 2.75 showed a higher number of main canals at all levels compared to those with aspect ratios < 2.75 at the 3-mm level. Additionally, the ≥ 2.75 group exhibited more accessory canals and a higher average number of accessory canals. The 3D assessment confirmed significantly more accessory canals and apical foramina in the ≥ 2.75 group. The prevalence of roots with apical deltas was nearly double in the ≥ 2.75 group, and middle mesial canals were exclusively found in this group. In the distal root, the ≥ 1.75 group showed a significantly higher number of main canals at all axial levels. No significant differences were observed between groups in terms of accessory canals, apical foramina, or deltas.
CONCLUSIONS: A higher root aspect ratio is related to higher anatomical complexity.
METHODS: This study used micro-CT imaging to analyze 163 two-rooted mandibular molars. The aspect ratios of the roots at the apical 3-mm level were categorized as \"< 2.75\" or \"≥ 2.75\" (mesial) and \"< 1.75\" or \"≥ 1.75\" (distal). A two-dimensional (2D) analysis focused on four apical axial cross-section levels to determine the presence of main and accessory canals and isthmus. Additionally, a three-dimensional (3D) assessment of the apical 4-mm of both roots examined main and accessory canals, apical foramina, apical deltas, and middle mesial canals.
RESULTS: Mesial roots with aspect ratios ≥ 2.75 showed a higher number of main canals at all levels compared to those with aspect ratios < 2.75 at the 3-mm level. Additionally, the ≥ 2.75 group exhibited more accessory canals and a higher average number of accessory canals. The 3D assessment confirmed significantly more accessory canals and apical foramina in the ≥ 2.75 group. The prevalence of roots with apical deltas was nearly double in the ≥ 2.75 group, and middle mesial canals were exclusively found in this group. In the distal root, the ≥ 1.75 group showed a significantly higher number of main canals at all axial levels. No significant differences were observed between groups in terms of accessory canals, apical foramina, or deltas.
CONCLUSIONS: A higher root aspect ratio is related to higher anatomical complexity.
摘要：
目的：本研究旨在探讨下颌磨牙根尖3-mm水平的长宽比与其根管复杂性之间的关系。
方法：本研究使用显微CT成像分析了163个双根下颌磨牙。根尖3毫米水平的根的长宽比分为“<2.75”或“≥2.75”（中间）和“<1.75”或“≥1.75”（远端）。二维（2D）分析集中在四个顶端轴向横截面水平上，以确定主管和副管和峡部的存在。此外,对检查的主管和副管的根尖4毫米的三维（3D）评估，顶端孔，顶端三角洲，中间运河。
结果：纵横比≥2.75的中根在所有水平上显示出比在3-mm水平上纵横比<2.75的中根更高的主管数量。此外,≥2.75组表现出更多的副运河和更高的平均副运河数量。3D评估证实≥2.75组中的副管和根尖孔明显更多。在≥2.75组中，根尖三角洲的患病率几乎翻了一番，中中中管只在该组中发现。在远端根部，≥1.75组显示所有轴向水平的主管数量均显着增加。在副管方面，组间没有观察到显著差异，顶端孔，或三角洲。
结论：较高的根长宽比与较高的解剖复杂性有关。
方法：本研究使用显微CT成像分析了163个双根下颌磨牙。根尖3毫米水平的根的长宽比分为“<2.75”或“≥2.75”（中间）和“<1.75”或“≥1.75”（远端）。二维（2D）分析集中在四个顶端轴向横截面水平上，以确定主管和副管和峡部的存在。此外,对检查的主管和副管的根尖4毫米的三维（3D）评估，顶端孔，顶端三角洲，中间运河。
结果：纵横比≥2.75的中根在所有水平上显示出比在3-mm水平上纵横比<2.75的中根更高的主管数量。此外,≥2.75组表现出更多的副运河和更高的平均副运河数量。3D评估证实≥2.75组中的副管和根尖孔明显更多。在≥2.75组中，根尖三角洲的患病率几乎翻了一番，中中中管只在该组中发现。在远端根部，≥1.75组显示所有轴向水平的主管数量均显着增加。在副管方面，组间没有观察到显著差异，顶端孔，或三角洲。
结论：较高的根长宽比与较高的解剖复杂性有关。
