Gu Yong-Chun, Zhang Yan-Ping, Liao Zhen-Gui, Fei Xue-Dong
Department of Dentistry, First People's Hospital of Wujiang, Medical School of Nantong University, Suzhou, China.
J Endod. 2013 Aug;39(8):973-6. doi: 10.1016/j.joen.2013.04.039. Epub 2013 May 31.
The purpose of this study was to quantitatively evaluate the wall thickness of C-shaped canals in mandibular first premolars using micro-computed tomographic imaging. The focus was on the relation between the radicular groove and the mesial canal wall thickness.
A total of 148 mandibular first premolars were scanned by a micro-computed tomographic scanner. After 3-dimensional reconstruction of the teeth, 29 specimens were identified to contain a C-shaped canal, and then they were analyzed in software Mimics 10.01 (Materialise, Leuven, Belgium). The buccal and lingual canal wall thickness, minimum mesial and distal wall thickness, and the depth and angle of radicular grooves were measured at different root levels. Two-way analyses of variance and the post hoc Tukey's honestly significant difference test were used to compare the groups in relation to canal wall thickness.
The buccal and lingual canal walls were significantly (P < .005) thicker than the mesial and distal walls. The minimum thickness of the mesial walls was significantly (P < .005) lower than that of the distal walls, and the locations were frequently at lingual sites, with an incidence of 67.3% for the mesial walls and 69.2% for the distal walls. Backward multivariate analysis showed that the root level and groove angle contributed significantly (P < .005) to the minimum mesial wall thickness.
The mesial walls of C-shaped canals in mandibular first premolars are the thinnest zones. The minimum mesial wall thickness decreases with the increased severity of the radicular groove, and it mainly occurs at lingual sites. Care should be taken to avoid perforation at danger zones during shaping and post space preparation procedures.
本研究的目的是使用显微计算机断层扫描成像技术对下颌第一前磨牙C形根管的管壁厚度进行定量评估。重点在于牙根沟与近中管壁厚度之间的关系。
使用显微计算机断层扫描仪对148颗下颌第一前磨牙进行扫描。在对牙齿进行三维重建后，确定29个标本含有C形根管，然后在Mimics 10.01软件（Materialise，比利时鲁汶）中进行分析。在不同牙根水平测量颊侧和舌侧根管壁厚度、近中和远中最小管壁厚度以及牙根沟的深度和角度。使用双向方差分析和事后Tukey真实显著性差异检验来比较各组之间的根管壁厚度。
颊侧和舌侧根管壁明显（P <.005）比近中和远中管壁厚。近中管壁的最小厚度明显（P <.005）低于远中管壁，且位置多在舌侧，近中管壁发生率为67.3%，远中管壁发生率为69.2%。向后多变量分析表明，牙根水平和沟角度对近中最小管壁厚度有显著贡献（P <.005）。
下颌第一前磨牙C形根管的近中管壁是最薄的区域。近中最小管壁厚度随着牙根沟严重程度的增加而减小，且主要发生在舌侧部位。在根管预备和桩道预备过程中，应注意避免在危险区域穿孔。
