CAJ | 학술논문

目的：测量下颌第二恒磨牙 C 型根的根管壁厚度。方法：采集到中国汉族患者拔除的 C 形根下颌第二恒磨牙40颗。显微 CT 扫描后采用 Mimics 10．01软件进行三维重建；沿着牙体长轴从釉牙骨质界（CEJ）到根尖顶每隔1 mm 连续虚拟横切牙根模型，观测牙根横截面上 C 形根管的类型（范兵分型），测量唇、舌侧以及近、远中参考位点的根管壁厚度。双因素方差分析及 LSD-t 检验比较不同方位的根管壁厚度。结果：40个下颌第二恒磨牙 C 形根被虚拟切割为370个根管横截面，其中C1根管126个（34．1％），C2根管46个（12．4％），C3根管160个（43．2％）。除了 CEJ 下10 mm 水平，舌侧根管壁最小厚度均值总是小于颊侧，而两者又均小于近、远中参考位点处的根管壁厚度。除了 CEJ 下12 mm 水平，4个测量位点根管壁厚度均值间的差异均有统计学意义（P ＜0．05）。C2和 C3根管的颊侧壁最小厚度在近中区最多见，C1根管颊、舌侧以及 C2、C3根管的舌侧壁最小厚度多位于中央区。结论：下颌第二恒磨牙 C 型根管舌侧根管壁较薄，是根管及桩道预备的危险区。
목적：측량하합제이항마아 C 형근적근관벽후도。방법：채집도중국한족환자발제적 C 형근하합제이항마아40과。현미 CT 소묘후채용 Mimics 10．01연건진행삼유중건；연착아체장축종유아골질계（CEJ）도근첨정매격1 mm 련속허의횡절아근모형，관측아근횡절면상 C 형근관적류형（범병분형），측량진、설측이급근、원중삼고위점적근관벽후도。쌍인소방차분석급 LSD-t 검험비교불동방위적근관벽후도。결과：40개하합제이항마아 C 형근피허의절할위370개근관횡절면，기중C1근관126개（34．1％），C2근관46개（12．4％），C3근관160개（43．2％）。제료 CEJ 하10 mm 수평，설측근관벽최소후도균치총시소우협측，이량자우균소우근、원중삼고위점처적근관벽후도。제료 CEJ 하12 mm 수평，4개측량위점근관벽후도균치간적차이균유통계학의의（P ＜0．05）。C2화 C3근관적협측벽최소후도재근중구최다견，C1근관협、설측이급 C2、C3근관적설측벽최소후도다위우중앙구。결론：하합제이항마아 C 형근관설측근관벽교박，시근관급장도예비적위험구。
Objective:To analyze the wall thickness of C-shaped canals in permanent mandibular second molars.Methods:40 ex-tracted permanent mandibular second molars with C-shaped root were collected from native Chinese and were scanned by micro-CT scan-ner.The specimens were reconstructed three-dimensionally by software Mimics 10.01.The roots were sliced from cemento-enamel junc-tion (CEJ)to apex with 1 mm intervals.The cross-sectional root canal configurations were classified into 5 types according to the Fan's Classification.The minimum buccal wall thickness (MBWT),minimum lingual wall thickness(MLWT)and their locations,as well as the wall thickness at the mesial and distal reference sites were detected.Two-way ANOVA and post hoc LSD-t tests were used to com-pare the mean thickness at 4 sides.Results:Among 370 cross-sections of 40 C-shaped roots,C1,C2 and C3 canals were observed on 126(34.1%),46 (12.4%)and 160 (43.2%)sections respectively.Except at the 10 mm level,the mean MLWT was always lower than MBWT;and the MLWT and MBWT were always lower than the wall thickness at the mesial and distal reference sites.The differ-ence was statistically significant (P <0.05)along the root length above the 12 mm level.The MBWT of the C2 and C3 canals was more likely located at the mesial region,and the MBWT of the C1 and the MLWT of C1,C2 and C3 was more frequently located at the center region.Conclusion:The lingual wall of C-shaped canal in mandibualr second molars was the thinnest zone among four sides,and care should be taken during root canal instrumentation and post space preparation to avoid perforation.