| Summary: | 碩士 === 高雄醫學大學 === 牙醫學研究所 === 98 === Purpose：The objectives of modern root canal therapy was to proper clean and shape the root canal system and complete removing the intracanal infection substance and sealing the system with a permanent sealing. Studies shows the sealer provides the seal and the percentage of the sealer should be as lower as possible in order to increase the long term sealing ability. Although it is difficult to use cold lateral compaction technique in curved canal, but the most clinical dentist still use it . The purpose of this study was to use two different tapered root canal enlargement and two different tapered master cone in curved canal obturation using cold lateral compaction technique, in order to find the effect of the taper of the root canal enlargement and the taper of the master cone on the percentage of GP filling using cold lateral compaction technique in curved canal.
Material and Method: 40 simulated canals in resin blocks with 16.5mm in length and a 32 degrees curve were divided to two groups in this study.
In the first group, root canal was prepared by using Gates-Glidden drills and K Flexo file files to an apical size 35 and the 0.1 tapered.
In the secondary groupe, root canal was enlargement by using SystemGP® (Dentsply France SAS) NiTi rotary instruments to an apical size 30 and the 0.06 tapered. Every group were divided into two subgroups (subgroup A and B)，and filled the canal by using 0.02-tapered and 0.06-tapered gutta-percha master cone. Type C NiTi finger spreader (Dentsply,Ballaigues,SWISS) was used for lateral compaction technique, and the compaction force was controlled at 2 Kg. All samples were sectioned at 2mm and 4 mm from the canal terminus by using low speed saw after stewing one week. The horizontal cutting surface was examined under microscope with 50 times magnifying power. The percentages of gutta-percha, sealer or voids to the total root canal area were calculated using software JMP 8.0.The data was to test the significant differences .Among the effect of the taper of the root canal enlargement and the taper of the master cone on the percentage of GP filling with ANOVA and Tukey-Kramer HSD test using JMP6.0 software package.
Result：Between the four groups which were cross-section at 2 mm from the canal terminus, the percentage of the area filled with gutta-percha were significant difference than the other groups (p<0.001).From the result of Tukey-Kramer HSD test, the group IIB was grater than the other three groups, and the group IIA was grater than the group IB. There was no significant different between other gropes. In the groups which was cross-section at 4 mm from the canal terminus, the percentage of GP filling was significant difference between etch groups(p<0.001).The result of Tukey-Kramer HSD test showed group IIB was grater than the others. There was no significant different in other groups. About the percentage of void, there was no significant different between the four groups which were cross-section at 2mm from the canal terminus, but the IIA group in the group which were cross-section at 4mm from the canal terminus was higher than IIB group(p=0.03).
Conclusion: When filling the curved canal by using lateral compaction technique, we could get the best percentage of GP filling if preparing the canal to 0.06-tapered and using 0.06-tapered master cone.
It showed the batter percentages no mater the cross-section at either 2 mm or 4 mm at canal terminus. If we prepared the canals to 0.01-tapered, the tapered sizes of master cons were no influences to the percentages of GP.
ge of GP was no influence by using the 0.02 tapered master cones filling curve canal by later compaction technique if we increased the canal tapered. But if we used 0.06 tapered master cones, the percentages of GP would be significantly decrease. We also found, if we enlarged the root canal to 0.06-tapered and filled with 0.02-tapered master cones, we have larger percentages of voids than using 0.06-tapered master cones at the cross-section at 4 mm of canal terminus
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