| Objective: Glucose quantitative analysis method was used to investigate the effect of cold gutta-percha lateral condensation on coronal leakage after phenol formaldehyde resin infiltrating into the inner and lateral walls of the root canal to seal the root canal wall before solidification,so as to provide relevant experimental basis for improving the success rate of root canal treatment in clinical practice.Methods: The crowns of 49 human permanent teeth with a single root canal were amputated from the cement-enamel junction transversely,and the reserved root length should be at least 12 mm.The root canal preparation was performed by K-type files using routine preparation technique combined with Gates-Glidden burs to flare the coronal.The isolated teeth after root canal preparation were randomly divided into three experimental groups: group A,group B and group C,with 15 teeth in each group,and two control groups:group D(positive control group)and group E(negative control group),with 2teeth in each group.In group B and group C,root canal walls were sealed with phenol formaldehyde resin after root canal drying,group A,D and E did not use phenol formaldehyde resin.When the root canal was filled,group A were filled with AH-plus sealer and cold gutta-percha using the lateral condensation technique.In group B,the root canal was obturated with AH-plus sealer and cold gutta-percha using lateral condensation technique after the phenol formaldehyde resin was completely solidified(about 5 hours).Group C were filled with AH-plus sealer and cold gutta-percha using lateral condensation technique immediately when the phenol formaldehyde resin had not yet solidified.Group D and group E were filled only with cold gutta-percha using lateral condensation technique.After the root canal obturation,the gutta-percha was cut off from the root cross section and the gutta-percha was pressed vertically.Finally,the length of the gutta-percha in the root canal was10 mm.All root canal filled teeth were placed in 37℃ and saturated humidity environment for 7 days until the filling material was completely solidified.Then,two layers of nail polish were applied to the root surface below the cross section and apical foramen above 2mm of the isolated teeth in groups A,B,C and D.In group E,two layers of nail polish were applied on the whole root surface(including root canal orifice and apical foramen).After nail polish was completely hardened,a model for glucose quantitative analysis of root canal microleakage was established,and glucose oxidase method was used to detect the concentration of glucose microleakage from the direction of coronal to the root canal apex on days 1,4,7,14 and 21.SPSS21.0 statistical software was used to conduct one-way ANOVA on the experimental data,and the coronal microleakage value was expressed as((?)±s).The test level was α=0.05 on both sides,and P<0.05 was a significant difference.Results:1.High concentration of glucose was detected in group D(positive control group)on the 1st day,while no glucose exudation was detected in group E(negative control group)from the 1st to the 21 st day.2.Compared with group A(root canal wall sealed without phenol formaldehyde resin)and group B(root canal wall sealed with phenol formaldehyde resin and filled after complete solidification),on day 1,4,7,14 and 21,respectively,the P > 0.05,that is,there was no significant difference in coronal microleakage between group A and group B at the same time point.3.Compared with group A(root canal wall sealed without phenol formaldehyde resin)and group C(phenol formaldehyde resin sealing root canal wall immediately filling),on day 1,4,7,14 and 21,respectively,the P >0.05,that is,there was no significant difference in coronal microleakage between group A and group C at the same time point.4.Compared with group B(root canal wall sealed with phenol formaldehyde resin and filled after complete solidification)and group C(phenol formaldehyde resin sealing root canal wall immediately filling),on day 1,4,7,14 and 21,respectively,the P > 0.05,that is,there was no significant difference in coronal microleakage between group B and group C at the same time point.Conclusions:1.After the root canal wall was sealed with phenol formaldehyde resin and completely solidified,the lateral condensation of gutta-percha had no effect on the coronal microleakage.2.After phenol formaldehyde resin sealing root wall,the lateral condensation with gutta-percha immediately when the phenol formaldehyde resin had not yet solidified had no effect on the coronal microleakag.3.After sealing the root canal wall with phenol formaldehyde resin,no matter whether the phenol formaldehyde resin solidified or not,the lateral condensation with gutta-percha had no effect on the coronal microleakage. |
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