Abstract：
OBJECTIVE: This retrospective study aims to analyze the root canal morphology of permanent mandibular incisors and the bifurcating/merging sites of root canal systems in children aged 9-12 in a Chinese subpopulation.Design Cone-beam computed tomography scans of 976 healthy, untreated and fully developed mandibular incisors were collected. Root canal morphology was identified by Vertucci\'s classification. Combined three-dimensional reconstruction and visualization techniques were used to locate bifurcating/merging sites in root canals.
RESULTS: Vertucci I was the most common classification of mandibular central incisors (42.3%) while Vertucci III was most common in mandibular lateral incisors (37.9%). Females more frequently showed Vertucci I classification (49.5% central incisors and 36.7% lateral incisors) while Vertucci III was most common among males (44.5% central incisors and 41.0% lateral incisors). The difference in canal classification by sex was statistically significant (p < 0.05). 58.7% of Vertucci V canals bifurcated in the apical third (AT) in central incisors, while 69.5% bifurcated in the middle third (MT) in lateral incisors. Bifurcating and merging in AT (44.3%) was the most common style of Vertucci III canals in central incisors, while bifurcating in MT and merging in AT (53.8%) was the most common in lateral incisors.
CONCLUSIONS: The root canal morphology of mandibular incisors in children aged 9-12 was different from that reported in previous studies on adults, and closely related to sex. Males had significantly greater canal variability than females. Lateral incisors had greater canal variability than central incisors. The bifurcating/merging sites were closely related to tooth type.
RESULTS: Vertucci I was the most common classification of mandibular central incisors (42.3%) while Vertucci III was most common in mandibular lateral incisors (37.9%). Females more frequently showed Vertucci I classification (49.5% central incisors and 36.7% lateral incisors) while Vertucci III was most common among males (44.5% central incisors and 41.0% lateral incisors). The difference in canal classification by sex was statistically significant (p < 0.05). 58.7% of Vertucci V canals bifurcated in the apical third (AT) in central incisors, while 69.5% bifurcated in the middle third (MT) in lateral incisors. Bifurcating and merging in AT (44.3%) was the most common style of Vertucci III canals in central incisors, while bifurcating in MT and merging in AT (53.8%) was the most common in lateral incisors.
CONCLUSIONS: The root canal morphology of mandibular incisors in children aged 9-12 was different from that reported in previous studies on adults, and closely related to sex. Males had significantly greater canal variability than females. Lateral incisors had greater canal variability than central incisors. The bifurcating/merging sites were closely related to tooth type.
摘要：
目的：这项回顾性研究旨在分析中国亚群中9-12岁儿童下颌永久切牙的根管形态和根管系统的分叉/合并部位。设计976例健康的锥形束计算机断层扫描，收集未经治疗和完全发育的下颌切牙。根管形态由Vertucci分类鉴定。结合三维重建和可视化技术用于定位根管中的分叉/合并部位。
结果：VertucciI是下颌中切牙最常见的分类（42.3％），而VertucciIII在下颌侧切牙中最常见（37.9％）。女性更频繁地显示VertucciI分类（49.5％的中央切牙和36.7％的侧切牙），而VertucciIII在男性中最常见（44.5％的中央切牙和41.0％的侧切牙）。按性别划分的根管分类差异有统计学意义(p<0.05)。58.7％的VertucciV管在中央切牙的根尖三分之一（AT）分叉，而69.5%的分支分布在侧切牙的中三分之一(MT)。AT的分叉和合并（44.3％）是中央切牙中VertucciIII管的最常见样式，而MT分叉和AT合并（53.8％）在侧切牙中最常见。
结论：9-12岁儿童下颌切牙根管形态与以往成人研究报告的不同，而且与性密切相关.男性的运河变异性明显大于女性。侧切牙的根管变异性大于中切牙。分叉/合并部位与牙齿类型密切相关。
结果：VertucciI是下颌中切牙最常见的分类（42.3％），而VertucciIII在下颌侧切牙中最常见（37.9％）。女性更频繁地显示VertucciI分类（49.5％的中央切牙和36.7％的侧切牙），而VertucciIII在男性中最常见（44.5％的中央切牙和41.0％的侧切牙）。按性别划分的根管分类差异有统计学意义(p<0.05)。58.7％的VertucciV管在中央切牙的根尖三分之一（AT）分叉，而69.5%的分支分布在侧切牙的中三分之一(MT)。AT的分叉和合并（44.3％）是中央切牙中VertucciIII管的最常见样式，而MT分叉和AT合并（53.8％）在侧切牙中最常见。
结论：9-12岁儿童下颌切牙根管形态与以往成人研究报告的不同，而且与性密切相关.男性的运河变异性明显大于女性。侧切牙的根管变异性大于中切牙。分叉/合并部位与牙齿类型密切相关。
