| ObjectiveThe residual smear layer is one of the main reasons for the failure of treatment.Removal smear layers from root canal with isthmus is one of the key issues in root canal treatment.The purpose of the present study was to evaluate the efficacy of the XP-endo finisher file on the debris and smear layer removal in premolars with isthmus compared with passive ultrasonic,sonic and conventional irrigation.MethodsExtracted premolars with isthmus which runs between two canals were selected by synchrotron radiation phase contrast CT(SR-PCCT)in this study.The specimens were separated at 1mm above enamelo-cemental junction using a high speed diamond disc under water.A size 10 K-file was placed into root canal until it became visible at the apical foramen by an operating microscope with a 10×magnification.The canal length was determined by subtracting 1 mm from that measurement.Instrumentation of the canal was prepared by using the Pro Taper rotary Ni Ti system up to size 30(F3).The teeth were randomly assigned to five groups(n=25)according to final irrigation protocol:group A,XP-endo finisher file;group B,passive ultrasonic irrigation;group C,sonic irrigation(MM1500);group D,conventional syringe irrigation and group E,control group.After finial irrigation,three-dimensional image reconstruction of the teeth were obtained by synchrotron radiation phase contrast CT.Then,the longitudinal grooves were made through the buccal and lingual surfaces of each root with a diamond disc,and then were split into 2 halves longitudinally by using a chisel and mallet.The specimen was dehydrated with ascending concentrations of ethyl alcohol(30–100 %)and was coated with gold.The upper,middle and lower sections of the isthmus were examined by using a scanning electron microscope(SEM)(SUPRA 55 VP Germany).Scoring of smear layer was performed at a ×1000magnification.All date analyses were performed by IBM SPSS 21.0 software.The differences of smear layer scores among the groups were analyzed by means of the Kruskal–Wallis test and the Mann–Whitney test.The level of significance was set at5 %.ResultsSR-PCCT showed: the dentin debris removal effect of XP-endo Finisher,ultrasonic irrigation,sonic irrigation MM1500 was better than that of 3 % Na Cl O and 17 % EDTA irrigation and control group.Smear layer removal results showed: The smear layer removal effect of group A,group B,group C and group D were better than group E,the differences were statistically significant(P<0.05).Comparison between the groups showed:Group A,group B and group C removed significantly more than group D(P<0.05);the smear layer removal effect of group A was better than group B,group C and group D in the upper and middle sections of the isthmus,the difference were statistically significant(P<0.05);group B and group C had no significant difference(P<0.05);there was no significant difference among group A,group B and group C in the lower sections of the isthmus(P<0.05).ConclusionsThe smear layer removal effect of XP-endo finisher file was the best compared with ultrasonic irrigation and sonic in the upper and middle sections of the isthmus.Due to the narrow root canal space or blocking of root canal bifurcation in the lower segment of the narrow,the removal of the smear layer have similar effect among the XP-endo Finisher file,passive ultrasonic irrigation and MM1500.Normal saline can not remove the smear layer effectively,and the effect of removing the dentin debris is poor.In the process of root canal preparation,3 % Na Cl O and 17 % EDTA solution without using any auxiliary equipment which can enhance cleaning effect removed less smear layer and dentin debris. |
PDF Full Text Request