不同根管处理方法对根管壁抗折力影响的研究

目的　比较预备与不预备的根管以及预备后充填与不充填的根管抗折力。方法　将 30颗人尖牙随机分为 2个实验组和 1个对照组 ,每组 10颗。实验组从牙颈部截去牙冠后进行根管预备。第 1组以Ultra为封闭剂 ,采用冷侧压方法充填 ;第2组根管预备后不充填 ;第 3组根管不作任何处理。所有标本进行抗剪切强度试验。结果　第 2组与其他 2组间差异有显著性 (P <0 .0 0 1) ,抗折应力值最低 (12 6 .182MPa) ;第 1组抗折应力值最大 (15 3.4 97MPa) ;第 1组和第 3组之间无统计学差异 (P>0 .0 5 )。结论　预备后不充填的根管抗折力低于未处理组和完善根管治疗组。使用封闭剂根充后的管壁抗折力增强。

The Effect of Different Root Canal Treatment Methods on the Root Resistance to Fracture

Objective To compare the resistance to fracture of the root canals after instrumentation or not.Methods Thirty canines with single canal were selected.The crowns of all teeth were sectioned at the cementoenamel junction and the teeth were randomly divided into two experimental groups and one control group,and each group had 10 teeth.After the two experimental groups being prepared by step-back technique ,the root canals of group 1 were obturated with gutta-percha cone and Ultra sealer using cold lateral condensation technique;the root canals of group 2 were instrumented but not obturated;the root canals of group 3 were neither instrumented nor obturated.All the samples were tested for stress and the resistance force to fracture was measured.Results Group 2 was significantly different from the others(P<0.001),and the resistance to fracture was the lowest (126.182 MPa). The resistance to fracture of group 1 was the highest(153.497 MPa).The difference between group 1 and group 3 was not significant(P>0.05).Conclusion The root canals that were instrumented but not obturated were significantly weakened.The root canals that were instrumented and obturated with gutta-pucha and sealer were significantly strong.