| Objective:Root canal is filled using AH-Plus combined with thermoplastic gutta-percha technology,and then,observing the condition and change trend of apical microleakage after post space preparation at different time points within one week,finding the time node for the difference of apical microleakage.This provides an experimental basis for the best post space preparation timing after root canal filled using AH-Plus in clinical work.Methods:(1)Tooth collection:collecting 110 maxillary single canal premolars due to orthodontic subtraction with complete apical development and the root canal curvature <10°were measured by Schneider method.(2)Grouping: according to the timing of the post space preparation after filling using AH-Plus combined with thermoplastic gutta-percha technology,the teeth were randomly divided into 11 groups(0h group(immediate group),8h group,1d group,2d group,3d group,4d group,5d group,6d group,7d group,non-prepared group and control group),10 teeth each group.The control group was divided into negative control group and positive control group,each group had 5 teeth.(3)Tooth processing: cutting off the crown to make the root remains 15 mm,using ProTaper prepares the root canal to F3(30#),and root canal filling using AH-Plus combined with thermoplastic gutta-percha technology(except the control group).(4)Post space preparation and making transparent tooth: according to the corresponding time of each group,the teeth were prepared with 5mm filling material left at the apex.The prepared teeth were put back into the incubator with 100% humidity and 37 C.After the last group is completed,making all the teeth immersed in Indian Ink for 1 week,and then making them transparent.(5)Data collection and statistical analysis: we can measuring the length of dye penetration using Vernier caliper under the microscope.Import all the data into SPSS21.0 for analysis,the results of each group were represented by `x±S,and the comparison was used by analysis of variance,therefore,we can valuing the degree and difference of the apical microleakage after post space preparation.Results:1.Compare the apical microleakage after post space preparation at different times using AH-Plus and thermoplastic gutta-percha technology,the apical microleakage was relatively small in the non-prepared group(0.80±0.47mm)and the 0h group(0.82±0.46mm).The apical microleakage increased gradually with the delay of post space preparation time,and the largest apical microleakage was in the 7d group(2.65±0.39mm).The results of analysis of variance showed that the microleakage values of each group were statistically different(F=29.573,P<0.001).2.The pairwise comparison between the groups showed that there was no statistical difference in apical microleakage between the groups of non-prepared,0h,8h,1d,2d and 3d(P>0.05),but there was a significant difference in apical microleakage compared with the groups of 4d,5d,6d and 7d(P<0.001).There was no significant difference in microleakage between the 5d and 4d groups(P>0.05).and there was no significant difference in microleakage between the 5d,6d and 7d groups(P>0.05).However,there were statistically significant differences in microleakage between the 4d group and the 6d and 7d groups(P<0.001).Conclusion:The apical microleakage caused by post space preparation within 3 days after root canal filling using AH-Plus and thermoplastic gutta-percha technology is small.From the 4th day after filling,there will have large apical microleakage after post space preparation,and the maximum apical microleakage will occur after one week.Therefore,it is suggested that post space preparation should be conducted within 3 days after root canal filling using AH-Plus sealer combined with thermoplastic gutta-percha technology in future clinical work.This can produce smaller apical microleakage,so as to ensure the tight sealing of the root canal system,prevent pathogens entering the root canal from the periapical tissue and causing re-infection,and improve the success rate of repair treatment. |
PDF Full Text Request