| Objective: Cortisomol paste and paste AH- plus is a widely used two kinds of clinical root canal filling materials, and has obtained the certain clinical effect.This experiment is to use the two paste for root canal filling in vitro teeth respectively, and then placed at different times after using hand equipment joint chloroform to grubbing tube fillings, by observing the residual quantity of root tube wall fillings and record each root canal working length of the time, contrast analysis AH- plus and Cortisomol paste on the teeth to remove the impact of the change and time, in order to provide the basis for clinical using.Methods: 60 single mandibular premolar, prepared by using stepback technique. Those teeth are out for orthodontic reduction, pulp and root canal without full absorption, without treatment, root development completely. AH-Plus group obturated by laterally condensed gutta-percha using AH-Plus as the sealer. Cortisomol group obturated by laterally condensed gutta-percha using Cortisomol as the sealer.Then Those obturated teeth will be filled in constant temperature box. Each group is divided into three subgroups, each subgroup of 10 teeth in vitro, respectively take out after 3rd day, 7th day and 30 th. Gutta-percha was removed with hand files and chloroform.Following data were recorded : time to reach the working length( T1),time required for the removal of gutta-percha( T2).Then the teeth were vertically split and the cleanliness of the root canal walls was evaluatedby Betti LV method.Results: 1.Comparison between groups working hours: T1 and T2 of Cortisomol group on the 3rd day, 30 th day were significantly less than that of AH-plus group(P < 0.05); On the 7th days there was no statistical significance between groups, but AH- plus group is significantly higher than Cortisomol group; Comparison among Cortisomol and AH-plus groups on the 3 rd day, 7th day and 30 th day, the longer the number of days the greater the values of T1 and T2,the difference was statistically significant(P < 0.05). The statistical result is T1(F = 17.719, 11.073, P < 0.001), T2(F = 67.058, 12.007, P < 0.001). 2.Comparison the difference of root canal wall cleanliness: AH- plus group regardless of 3rd day, 7th day and 30 th, root 1/3 score were the highest in the all. The difference of root canal wall cleanliness was statistically significant on the7 th day of AH-plus group, apical 1/3 respectively compared with root 1/3 and crown 1/3(P < 0.05), and root 1/3 was significantly higher than apical 1/3 and crown 1/3; no significant difference between the latter two parts score. In Cortisomol group, there was no statistical significance. Cortisomol group on the 3rd day, root 1/3 was significantly higher than apical 1/3 and crown 1/3; on 7th day and 30 th, score of the crown 1/3 was the highest, and there was no statistically significant difference. In Cortisomol group, there was no statistical significance.Conclusion: This experiment showed that in the root canal retreatment, Cortisomol groups remove root canal fillings more easily than AH-plus groups, and retreatment of primary root filling in a shorter interval time shows higher removal efficiency.But time is not significant influence on the root tube wall cleanliness. In clinic,cortisomol should be priority used if there existed a risk of retreatment. However, this experimental research was single using the hand instruments on the influence of different root canal filling material removal, and to use different devices with different root canal filling material removal effect still need further research. |
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