| Objectives The in vitro experiments(in vitro as samples),1%,1.5%,2%Tween-80 observed(polyoxye-thylene sorbitol fatty acid ester-80)and 17%EDTA(ethylenediaminetetraacetic acid)+ 1%Na Cl O with ultrasonic irrigation smear layer removal,the corrosion degree and resin type root canal filling paste for root canal filling after root fracture resistance and apical sealing the effect of root canal,for improving the success rate of root canal therapy to provide experimental basis for.Methods Experiment 1 40 single root canal detached premolars were randomly divided into 4 groups.The crown was cut off,and the root canal was prepared to F3 by hand Protaper nickel titanium root canal filing.In the process of root canal preparation,each replacement was used in group A: 17%EDTA+1%Na Cl O ultrasonic rinse;group B: 17%EDTA+1%Na Cl O+1%Tween-80 ultrasonic irrigation;C group: 17%EDTA+1% Na Cl O+1.5%Tween-80 ultrasonic irrigation;D group: 17%EDTA+ 1%Na Cl O+2% Tween-80 ultrasonic flushing,root canal irrigation.The samples were split and one of them was randomly selected to be drilled at 3mm,6mm,and 9mm from the root tip.The nail oil was painted outside the part of the inner wall of the root canal,fixed,dehydrated,dry and spray gold.The root canal smear layer removal and corrosion level of each section were observed under electron microscope with a 2000 fold view.Experiment 2 40 single root canal detached premolars were divided into groups and preparatory methods.Gutta percha root canal filling,confirm the root canal filling tight,zinc polycarboxylate cement filling.The sample was embedded in the hyper anhydrite with the root cross section high out of the gypsum plane 9mm and placed on the DZS-III hard material performance tester.The velocity was adjusted to 1mm per minute until the root fracture records were recorded.Experiment 3 56 single root canals were taken in vitro.The group and preparation method were the same as experiment one,plus two groups of control group X and Y,each group had 8 isolated teeth,X group and Y group were 17%EDTA+ 1% Na Cl O as washing liquid,the root canal preparation method was the same as the experiment.The experimental group and the Y group were filled with root canal filling with the gutta percha lateral pressure method,and the X-ray films were used to confirm the root canal filling.Group X was not filled with root canal.In the experimental group and the X group,the nail oil was coated on the root tip of the root surface of the tooth root with double nail polish,and the root surface of group Y(including the apex hole area)was coated with double nail polish.In the 100% humidity environment,keep it for 7 days in the 37 degree sterile thermostat box.At 1,3,7,14,21 and 30 days,the glucose concentration was measured by glucose oxidase colorimetric assay in all the isolated teeth in the glucose quantitative analysis root canal microleakage model.The glucose oxidase was measured in the glass bottles at 1,3,7,14,21 and 30 days.Results 1 In root 1/3,there was no significant difference in scavenging and corrosion degree of root canal wall(P>0.05),but in root 1/3 and root apex 1/3,with the increase of Tween-80 concentration,the difference of scavenging layer and corrosion degree was statistically significant(P<0.05).2 The differences in flexural strength of the isolated teeth using Tween-80 compared with those without Tween-80 were statistically significant(P<0.05);the flexural strength of 1% Tween-80 and 1.5% Tween-80 increased with the increase of Tween-80 concentration(P<0.05),and the flexural strength of the 2% Tween-80 ultrasonic flushing was lower than the use of 1.5% Tween-80.The difference between the experimental group and the control group was statistically significant(P<0.05).3 The microleakage of the isolated teeth using Tween-80 was smaller than that of the isolated root of Tween-80,and the microleakage of 1% Tween-80 and 1.5% Tween-80 decreased with the increase of Tween-80 concentration,and the difference was statistically significant(P<0.05).The microleakage was lower than that of the experimental group using 1.5% Tween-80 after 2% Tween-80 ultrasonic flushing.Statistical significance(P<0.05).Conclusions 1 According to the analysis of the removal of the root canal smear layer,the higher the concentration is,the cleaner the smear layer is removed.The best removal effect of 2%Tween-80 and 17%EDTA+ 1%Na Cl O is combined with the ultrasonic flushing layer.The higher the corrosion degree,the higher the concentration,the heavier the corrosion degree,and the heaviest corrosion of 2%Tween-80 and 17%EDTA+ 1%Na Cl O.2 As far as the bending resistance of root canal filling is concerned,the higher the anti folding performance is in a certain range,the flexural resistance of 1.5%Tween-80 and 17%EDTA+ 1%Na Cl O combined ultrasonic flushing is the best,but the combined ultrasonic flushing of 2%Tween-80 and 17%EDTA+ 1%Na Cl O is weaker than that of 1.5%Tween-80.3 As for the effect of apex sealing,the better the concentration is,the better the sealing ability is,the best of the apex sealing is 1.5%Tween-80 and 17%EDTA+ 1%Na Cl O,but the combination of 2%Tween-80 and 17%EDTA+ 1%Na Cl O in ultrasonic flushing is better than that of 1.5%Tween-80. |
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