The Vitro Study On Effects Of Root Canal Preparation By Different Instrumentation And Irrigation

Background: root canal preparation is crucial step of root canal therapy, including cleaning and shaping of root canal by mechanical instrumentation and irrigation.Objective: to investigate the effects of root canal preparation by different instrumentation and irrigation containing surface active agent(SAA).Methods: Part I : The fresh extracted 60 single-rooted teeth were collected,then random distributed in 6 groups of 10 each. Group 1, the negative control; group 2, reaming instrumentation with reamers only; group 3, reaming and filing instrumentation with reamers and K files; group 4, reaming and filing instrumentation with reamers and H files; group 5, filing instrumentation with K files only; group 6, the ultrasonic instrumentation. The effects of canal preparation were evaluated by Scanning electron microscopic photomicrographs.Part II :Screen the best SAA irrigation from the 3.4%AEO, 2%SDS, l%tween-80. The fresh extracted 60 teeth were random stratified distributed in 6 groups of 10 each. Group 1, the negative control; group 2, screening SAA irrigation; group 3, 10%EDTA; group 4, 10% EDTA+ screening SAA irrigation; groupS, 10% EDTA and 1% NaCLO in turn. Group 6, 1% NaCLO and 3%H2O2 in turn. The effects of canal preparation were evaluated by Scanning electron microscopic photomicrographs.At the same time, the effects of infected and uninfected root canal which have the same baseline were compared.Results: Part I : the debris area of the root canal wall of group 5 was the largest, followed by group 2, group 3, group 1, group 4 and group 6. There was significant difference between the group5/group2/group3 and the other groups(P<0.05). However, there was no significant difference among the last three groups(l,4&6) (P <0.05).Part II: the dentin tuble opening degree of 3.4%AEO is superior to 2%SDS and l%tween-80,and the debris area of AEO group is smaller than the other. The second experiment show that the area of bebris of H2O group is the largest,followed by the mixture of EDTA and AEO, NaCLO and H2O2 inturn, .there was significant difference between any of the above three group and the others. AEO, EDTA; EDTA and NaCLO in turn show good effect. There was no significant difference among the three groups. There was no significant difference between the infected root canal and the uninfected root canal.Conclusion: Part I : the effect of the ultrasonic treatment and the reamer and H file treatment were the best. K file or reamer file can not effectively remove the debris. The result is useful for the canal preparation in endodontic therapy.PartII:the effect of root canal cleaning by 3.4%AEO is superior to 2%SDS and l%tween-80. 3.4%AEO alone is harmless to human and maybe the promising root canal irrigation. When study the effect of the root canal irrigation by SEM, there is no difference between the infected root canal and the uninfected root canal. The smear layer is dramatic relative to mstruments,irrigations, and preparing methods.