UNASSIGNED: Thirty-two single-rooted human-extracted premolars were used. They were mounted in wax, and preoperative cone-beam computed tomography (CBCT) scans were taken with 11 × 8 Field of view (FOV). The evaluation of the pericervical dentin thickness was done at the cementoenamel junction level. After pre-CBCT, the 32 samples were divided into four groups (n = 8) - Group A: fixed tapered hand files, Group B: variable regressive tapered TruNatomy, Group C: progressive tapered ProTaper Gold, and Group D: fixed tapered HyFlex EDM. Following instrumentation, postoperative CBCT scans were taken to evaluate pericervical dentin thickness. Obturation was done and access cavity was restored with composite. Fracture strength was checked for all the samples using \"universal testing machine\" until fracture, and calculated in newtons (N).
UNASSIGNED: Student\'s t-test and ANOVA test, along with Tukey\'s post hoc analysis, were used for comparing mean values between the groups, and P < 0.05 was considered statistically significant.
UNASSIGNED: The results of this study showed that there is no statistically significant difference in preserving pericervical dentin with file system of different types of taper and fracture resistance between the groups.
UNASSIGNED: Within the limitations of the study, it was concluded that different types of file taper systems used for root canal preparation have no significant effect on the preservation of pericervical dentin and fracture resistance of teeth.
■使用了32个单根人类提取的前磨牙。它们装在蜡中,术前锥形束计算机断层扫描(CBCT)扫描11×8视场(FOV)。在牙釉质交界处进行宫颈牙本质厚度的评估。在预CBCT之后,将32个样本分为四组(n=8)-A组:固定锥形手档,B组:可变回归锥形真理,C组:渐进锥形ProTaperGold,和D组:固定锥形HyFlex电火花加工。在仪器之后,术后进行CBCT扫描以评估宫颈牙本质厚度。完成填充,并用复合材料恢复进入腔。使用“万能试验机”检查所有样品的断裂强度,直到断裂,并以牛顿(N)计算。
■学生t检验和方差分析检验,以及Tukey的事后分析,用于比较组间的平均值,P<0.05被认为具有统计学意义。
■这项研究的结果表明,在保留不同类型的锥度和抗骨折性的文件系统的子宫颈牙本质方面,各组之间没有统计学上的显着差异。
■在研究的局限性内,结论不同类型的牙锥度系统用于根管预备,对保存颈管牙本质和牙齿抗折能力无明显影响。