根管直径和锥度对根尖微渗漏影响的实验研究

目的:探讨根管直径和锥度对根尖微渗漏的影响。方法:选取单根管下颌第二前磨牙为研究对象,根据根尖段直径和锥度分组,选取15颗牙,要求:距离解剖性根尖孔1mm根管直径(近远中径及颊舌径)<0.3mm、根尖段(距离解剖性根尖孔5mm)根管锥度(颊舌向及近远中向)<0.09,作为A组。另选取30颗牙,要求:距离解剖性根尖孔1mm根管直径(近远中径或颊舌径)>0.3mm、根尖段(距离解剖性根尖孔5mm)根管锥度(颊舌向或近远中向)>0.09,随机分为B、C组,另有阳性对照组5颗和阴性对照组5颗。实验牙均用Pro-taper镍钛根管锉统一预备至F3号,A、B组实验牙采用冷牙胶侧方加压法充填,C组采用热牙胶连续波垂直加压充填。经1%美蓝染色后剖开,观测染料渗入长度。结果:A组(1.65±0.61)mm,B组(3.06±0.74)mm,C组(1.79±0.53)mm,方差分析,各组染料渗入差异有统计学意义(P<0.05),两两比较,A组

Experimental Study on Apical Microleakage with Different Diameter and Taper

Objective:To study the apical microleakage of root canals with different diameter and taper after root canal therapy.Methods:The human mandibular second premolars with single root canal were selected.The teeth were divided into three groups according different diameters and tapers of the apical part of root canals.Group A(15 teeth) require mesiodistal(MD) and buccoligual(BL) diameters of root canals at 1mm from apical foramen are less than 0.3mm and MD and BL tapers of root canals at 1mm to 5mm from apical foramen are less than 0.09.Group B(15 teeth) and group C(15 teeth) require MD or BL diameters of root canals at 1mm from apical foramen is larger than 0.3mm and MD or BL tapers of root canals at 1mm to 5mm from apical foramen is larger than 0.09.Another 10 teeth served as the positive and negative controls.All root canals were prepared using Pro-taper instruments to F3.Group A and group B were obturated with cold lateral condensation technique.Group C was obturated with continuous wave vertical condensation technique.Apical microleakage was determined by using dye penetration test and measured by stereomicroscope.Results:Apical microleakage lines of group A had mean length of(1.65±0.61)mm.Apical microleakage lines of group B had mean length of(3.06±0.74)mm.Apical microleakage lines of group C had mean length of(1.79±0.53)mm.Difference between group A and group B was statistical significance.Difference between group B and group C was statistical significance.Conclusion:With cold lateral condensation technique,the apical microleakage of root canals which diameter and taper are larger than file is larger than that one diameter and taper are smaller than file.Continuous wave vertical condensation technique has better apical sealing ability in root canals which diameter and taper are larger than file.