K锉初步预备和扭矩对机用ProTaper抗折性能的影响

目的探讨K锉初步预备和扭矩对机用ProTaper抗折性能的影响。方法分别计算各组机用ProTaper器械折断或变形前所预备的S型树脂模拟根管的数目。结果A1组（模拟根管未经K锉初步预备）S1预备了13个模拟根管；B1组（模拟根管经K锉初步预备）s1预备了36个模拟根管；A2组（低扭矩组）S2预备了17个模拟根管；B2组（高扭矩组）s2预备了18个模拟根管；A3组（低扭矩组）F1预备了14个模拟根管；B3组（高扭矩组）F1预备了14个模拟根管；A4组（低扭矩组）F2预备了6个模拟根管；B4组（高扭矩组）F2预备了6个模拟根管。结论根管经K锉初步预备可降低机用ProTaper器械折断的发生；扭矩的高低对机用ProTaper器械的抗折性能没有明显影响。

Influence of K file preflaring and torque on the separation of ProTaper rotary instruments

Objective This study aims to investigate the influence of K file preflaring and torque on the failure of rotary nickel-titanium ProTaper instruments. Methods An in vitro method was carried out to calculate the mean number of S-shaped simulated root canals before file fracture or deformation under different conditions. Results Group AI（S1 on simulators with no preflaring） shaped 13 blocks, and Group Bl（S1 on manually preflared simulators） shaped 36 blocks. Group A2（S2 with low torque） shaped 17 blocks, and Group B2（S2 with high torque） shaped 18 blocks. Group A3 （F1 with low torque） shaped 14 blocks, and Group B3（F1 with high torque） shaped 14 blocks. Group A4 （F2 with low torque） shaped 6 blocks, and Group B4（F2 with high torque） shaped 6 blocks. Conclusion K file preflaring is a major determinant in reducing the failure of rotary nickel-titanium ProTaper instruments, whereas torque exhibiting no influence on the failure of rotary nickel-titanium ProTaper instruments.