الفهرس 
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Abstract
Summary
In recent years, calcium silicate based-sealers attracted much attention owing to their superior properties. The use of calcium silicate-based sealers with a SC obturation technique is popular nowadays. However, the SC technique still has its drawbacks. The use of warm vertical compaction obturation technique with a bio-ceramic sealer may have a negative effect on its fluidity and ability to penetrate deep into dentinal tubules.
There is a gap in the literature regarding the evaluation of the depth of dentinal tubule penetration of these sealers when used with different obturation techniques.
The investigation of the ability of bio-ceramic sealers to be completely removed from the root canals system is of major concern, specifically when these sealers are used with different obturation techniques.
The aim of this study was to compare the effect of different obturation techniques (SC versus WVC) on the sealer penetration into dentinal tubules and its effect on the re-treatability and cleanliness of the dentinal tubules of the teeth after retreatment procedure.
Part I samples (16 roots) were prepared and obturated with either SC or WVC technique. After the complete setting of the sealer, every sample was sectioned into three parts and examined under SEM to evaluate dentinal tubule penetration.
Part II samples (32 roots) were prepared and obturated as previously described. After 21 days, samples were retreated using either Protaper retreatment files or Edge files. Every sample was examined under SEM for evaluation of canal cleanliness. Time taken to reach the full working length and patency was also recorded.
There was no significant difference between SC & WVC regarding dentinal tubule penetration.
Regarding canal cleanliness, there was no difference between different subgroups in coronal region. In the middle third, no difference was found regarding dentinal tubule penetration when there were retreated with the Protaper files. The EdgeFile removed more debris from canals in group II than with canals in group I.
No significant difference between the two retreatment files when used in SC group. While in WVC group, EdgeFile was significantly better than Protaper files in removing more debris from the middle region of the root canals.
In the apical third, Protaper removed more in WVC group rather than in SC group, while EdgeFile showed no significant difference regarding the percentage of remaining debris when any of the two obturation technique was used. EdgeFile was significantly better than Protaper files in removing more debris from inside the root canals.
Conclusion:
Under the circumstances of this study, the following can be concluded:
1- The obturation technique has no impact on dentinal tubule penetration of the sealer.
2- No file in the two selected systems could completely remove the sealer from the canals, especially apically.