| Objective:In this study, MTA and root canal filling material as the root canal sealer were applied to help gutta-percha point fill root canals. Compared the condition of apical micro-leakage after filling root canals. At the same time, observed the driving fit condition between the root canal sealers and the root canal wall through Scanning electron microscopy (SEM).Then assessed their sealing ability comprehensively and providing some relating theories, to explore the possibility the MTA is used clinically as root canal sealers.Methods:60fresh secondary single-rooted teeth or premolars were collected, which were removed for periodontal disease and orthodontic requirement. There should be no caries, well-growed root tips and no treatment on dental pulp in these teeth.1-, The tooth canals were prepared with standardized system. Divided the prepared teeth into two experimental groups Group A and B, and control groups Group C and Group D at random,10teeth in each group. Group A and B took MTA and root canal filling material paste added separately gutta-percha point by the way of the cold gutta-percha presses laterally to seal root canals. Group C and D did not take root canal sealers, only seal root canal with standardized system. Among them, group C was the positive control group, group D was the negative control group. After the root canals were well-filled, put all teeth in37℃,100%humidity incubator seven days to ensure the root canal sealers completely solidifying, then took them out.Group A、B、 C smear uniformly2layers of nail polish on root surface at the distance from root foramina more than1mm, while group D smear from the root foramina to root surface, placed them stilly for24hours. Next, deal with these teeth by Indian ink to dye. H2NO3decalcification, Observed and measured the length which the dyestuff seeped into the inside root canal wall under the stereoscopic microscope(X20). The measurement data were taken into statistical treatment with the ANOVA and SNK tests.2、The tooth canals were prepared with Method1. Divided the prepared teeth into A and B two groups, Group A was the experimental group and Group B was the control group,10teeth in each group. Group A and B took MTA and root canal filling material paste added separately gutta-percha point by the way of the cold gutta-percha presses laterally. Crosscut the root from one-third area of the root middle (5-6mm from the apex) and the root apex(2-3mm from the apex). All specimens were dry, sanding, vacuum spraying gold film, get the driving fit condition between the root canal sealers and the root canal wall under the SEM(X100, X500, X1000). Results:1、The length of the seeping colourant of group A、B、C were(0.296±0.155)mm,(0.695±0.238)mm,(1.527±0.375)mm. Negative control group D had no colourant seeping into. Group A had significant differences with group C(P<0.01), Group B had significant differences with group C(P<0.01), Group A had significant differences with group B(P<0.05)。2、Through the SEM, MTA was found to had better sealing ability after root canal filling than root canal filling material. There was no obvious crack.3、Both MTA and root canal filling material had good sealing ability in One-third area of root middle than root apex.Conclusions:MTA used as the root canal filling material, driving fit with the root canal wall tightly, showed better sealing ability. It has good sealing effect on root apex as well. In addition, it could effectively prevent the occurrence of apical micro-leakage. But further observation will need long-time treatment. |
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