الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Success of endodontic root canal treatment is multifactorial, yet, achieving maximum seal of the prepared root canal, both coronally and apically, remains one of the critical factors for success to prevent re-infection and entomb the remaining bacteria. The widespread use of NiTi files and matched taper gutta percha allowed recruitment of single cone technique as an obturation technique. Also, Introduction of calcium silicate-based materials led to paradigm shift in conventional techniques used for obturation, therefore their effect on different aspects of the root canal treatment was of concern and led to conduction of many studies to evaluate their efficiency.
This study aimed to evaluate the sealing ability and retrievability of a newly introduced bio-ceramic sealer (Well-Root ST) compared to an epoxy resin-based sealer (AH Plus), using single cone technique or cold lateral compaction.
Sixty recently extracted human permanent single rooted mandibular premolars were selected. Teeth were divided into 3 groups (n=20) according to the method of obturation. Each group was further subdivided into 2 subgroups (n=10) according to the method of evaluation. Teeth were decoronated, prepared, obturated, then incubated to ensure complete setting of the sealers.
After incubation, the 30 teeth recruited in groups for evaluation of sealing ability were transversely sectioned to obtain 2-mm thick-section from each third of each root. Sections of samples were observed under stereomicroscope at 40x, then stereomicrographs were captured using digital video camera and studied using ImageJ software to evaluate and assess the percentage of voids in the canal portion of sections.
The 30 teeth recruited in groups for evaluation of retrievability were retreated, then longitudinally sectioned. Sections of samples were observed under digital operating microscope at 16x, then photomicrographs were captured using digital video camera and studied using ImageJ software to evaluate and assess the percentage of remaining obturation material. The mean time required for retreatment was also measured.
The results of sealing ability test showed that there is no statistically significant difference regarding voids’ area percentage between SCT/Well-Root ST and CLC/AH Plus in all canal sections. Yet, there is a statistically significant difference between CLC/Well-Root ST and the other two groups, with the former is the higher. Also, the results showed that the apical section of all groups showed either no voids or lesser area of voids when compared to middle and coronal sections.
The results of retrievability test showed that there is a statistically significant difference between the three study groups regarding the percentage of remaining obturation material. There is no significant difference between the three canal sections of samples in each study group, except for the middle section group in CLC/Well-Root ST group in comparison with the coronal and middle section group of the same study group. In addition, there is a significant difference between the three study groups regarding the mean time required for retreatment procedure.