目的

探讨下颌前牙根管根尖部的内径、横截面形态和锥度。

方法

采用Digora 间接数字化成像技术拍摄481 颗下颌前牙的近远中向和颊舌向X 线影像，分析根管的分型、根管根尖部内径、横截面形态和锥度。

结果

下颌前牙以Ⅰ型根管为主，但仍有25.46%的下颌切牙和13.21%的下颌尖牙出现Ⅱ、Ⅲ和Ⅳ型根管。 在Ⅰ型根管中，颊舌径（中间值）大于近远中径（中间值），且下颌切牙和尖牙距根尖1 mm 处颊舌径的中间值为0.32 mm；下颌前牙颊舌向锥度大于近远中向锥度，颊舌向锥度的中间值大于0.10。

结论

下颌前牙的根管根尖部形态较为复杂。 预备单根管下颌前牙时主尖锉应选用至少35^# 的根管锉，并配合根管冲洗、改良根管预备和加强消毒等技术，以达到完善的根管治疗效果。

Objective

To investigate the root canal diameters，cross-section morphology and tapers of the root canal apical part of human mandibular anterior teeth.

Methods

A total of 481 mandibular anterior teeth were examined by Digora indirect digital radiography both from buccolingual and mesiodistal directions. Root canal types，root canal apical part diameters，cross-section morphology and tapers were analyzed.

Results

The major sort of mandibular anterior teeth was type Ⅰ，while 25.46% mandibular incisors and 13.21% mandibular canines were typeⅡ，Ⅲand Ⅳroot canals. In the typeⅠroot canals，buccolingual diameters （median） were larger than mesiodistal diameters （median），and the buccolingual diameter （median） at 1 mm from apex was 0.32 mm. In the mandibular anterior teeth，buccolingual tapers were larger than mesiodistal tapers，and the buccolingual tapers （median）were more than 0.10.

Conclusions

Mandibular anteriors' root canal apical morphology is quite complicated. To archive perfect clinical treatment effect of mandible anterior teeth，the master point file should select at least 35^# root canal files cooperated with root canal irrigation，modified root canal preparation technique and strengthen disinfection technique.