根管镍钛锉几何外形对弯曲根管预备效果影响的研究OA

Objective:To investigate the effect of root canal NiTi instruments geometry on the preparation of curved root canals by evaluating the effect of NiTi instrumentation systems with different geometrical and identical alloy phases and kinematics on the preparation of 3D printed significantly curved root canals.Methods:Twenty 3D printed root canal prepara-tion modules with 30° curvature and 20 with 50° curvature were divided equally into four groups(30° U-Gold group,30° X-Gold group,50° U-Gold group,50° X-Gold group).These groups were subjected to root canal preparation,CBCT scanning,3D reconstruction.The separated root canals were digitally compared with a standard root canal model of the corresponding curvature,cleanliness and transportation were calculated,and statistical analysis was performed.Results:X-Gold cleaned the 30° and 50° curved root canals better than the U-Gold(P＜0.05),with less over-preparation on the inside of the curved root canal than the U-Gold and less under-preparation on the outside of the curved root canal than the U-Gold.The transportation in the middle 1/3 and apical 1/3 of the 30° root canal were less than the U-Gold(P＜0.05),and in the 50° root canal the transportation in the middle 1/3 and apical 1/3 segments were smaller than in the U-Gold(P＞0.05),but not statistically dif-ferent.Conclusion:The geometry of the root canal NiTi instruments has an effect on both cleanliness and transportation of se-verely curved root canal preparations.NiTi instruments with an off-axis,rectangular cross-sectional geometry are more suitable for the preparation of severely curved root canals because they clean the curved canals better and produce less deflection in the middle and apical third of the canal than NiTi instruments with a coaxial,modified triangular cross-section.