Effects Of Root Canal Wall With Phenoaldehyde Resin On Coronal Microleakage With Cold Lateral Compaction Technique

Objective: In order to increase the sealing ability of root canal system and provide clinical basis for improving the success rate of root canal treatment,we investigated the effect of root canal wall with phenoaldehyde resin on coronal microleakage.Methods:Sixty-four extracted human permanent teeth with a single straight root canal were selected for this study,sixty of them were assigned to six experimental groups(n=10),Group A1B1,Group A2B1,Group A1B2,Group A2B2,Group A1B3 and Group A2B3.The other four samples were divided into two control groups(n=2),Group C(positive control group)and Group D(negative control group).All crowns were cut off on the vertical axis at cement-enamel junction.Cleaning and shaping with K files using technique followed by using Gates-Glidden drills to flare the coronal.The root canal wall of Groups A1 were sealed with phenoaldehyde resin,while Groups A2,C,D were not sealed.All the teeth in experimental groups were obturated with a root canal sealer and gutta-percha points using the cold lateral condensation technique.ZOE was used in Groups B1,AH Plus sealer was Groups B2 and GuttaFlow was Groups B3.In the control groups,sealers were not used.After obturation,removed gutta-percha points from root orifice with a heat carrier and ensured the length is 10 mm.Then radiographs were taken to evaluate the obturation.All samples were placed in an incubator at the controlled temperature of 37? with 100% humidity for 7 days.The roots in experimental groups and Group C were coated with two layers of clear nail varnish except for the apical 2mm and the root canal orifice,teeth in the negative control group D had the entire root surface coated with nail varnish.Once the nail varnish was absolutely dry,all the teeth were connected to the microleakage test device.Microleakage was measured by detecting the concentration of leaked glucose in apical reservoir at 1,4,7,14,and 21 days with the hexokinase method(HK method)on the AU5800 automatic biochemical analyzer.Because the amount of glucose microleakage was equal to the detected glucose concentration,so as to obtain the amount of glucose exuded from the apical foramen in each teeth.The total number of glucose microleakage from the day 1 to this moment was obtained by summing up all previous measurements in the same sample.Statistical Package for Social Science(SPSS)version 21.0 was used for data processing,and the data were analyzed with ANOVA of 2 ? 3 factorial design,and statistical significance was set at P<0.05.Results:1.No glucose microleakage was detected in the negative control group(Group D)from the 1st day to the 21 st day,while a large amount of glucose microleakage occurred in the positive control group(Group C)at the first day,and the amount continued to increase.2.The effect of root canal wall sealing with phenoaldehyde resin(factor A)on coronal microleakage: no significant difference of coronal microleakage was found between Group A1 and A2 at 1,4,7,14 and 21 days(P>0.05).3.The effect of root canal sealers(factor B)on coronal microleakage: no significant difference of sealing ability was found among test groups at 1,4,7,14 and 21 days(P>0.05).4.The interaction between phenoaldehyde resin and root canal sealers(factor A×B): there was no interaction between the two factors at 1,4,7,14 and 21 days(P>0.05).Conclusions:Root canal wall with phenoaldehyde resin has no effect on coronal microleakage,which can improve the sealing ability of root canal system.