الفهرس 
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Abstract
A successful endodontic treatment on several factors, however the most important objective is to achieve a tridimensional RC obturation to provide optimal coronal and apical seal, and entomb the remaining bacteria. After RC chemo-mechanical preparation, GP in conjunction with sealer is the standard material used to fill the canal. It is well known that appropriate physiochemical properties are recommended for RCSs such as low solubility, good sealing ability, bonding to dentin and biocompatibility. Recently with the introduction of calcium silicate materials in endodontics, the need to assess their physical, chemical, and mechanical properties have arouse to determine their efficiency to be used as RCSs.
This study aimed to evaluate the solubility, sealing ability, and dentin bonding strength of a newly introduced BC sealer (CeraSeal) compared to those of MTA-Fillapex, and Adseal.
For solubility testing, twenty-four sealer discs were prepared and incubated until complete setting of the sealers. The discs were divided into three groups (n = 8) according to the sealer’s type and then weighed (initial weight) using a precision balance to 0.0001 g. Then they were immersed in 50 ml of HBSS at 37°C. At 1, 7, 14, 21, and 27 days intervals, the discs were removed from the containers and dried in a drying oven for four days, reweighed, and then re-immersed in a new HBSS. Solubility was calculated as percentage of mass loss on each day and then the mean solubility was taken. Results were tabulated and statistically analyzed.
The results showed that in this study, there was statistically significant difference in the solubility of the three sealers with MTA-Fillapex showing the highest solubility at all times except after 24 hours where CeraSeal had higher solubility. All sealers showed progressively increasing dissolution over time reaching maximum solubility values at day (28). Both MTA-Fillapex and CeraSeal had solubility values which exceeded that recommended by the ISO specification No. 6876:2012 (i.e., 3%).
For the sealing ability evaluation, twenty-four extracted single rooted sound human teeth were decoronated, prepared, and obturated with one of the three sealers (n = 8). Then the roots were covered with three layers of nail varnish sparing the apical 2 mm from the apex. Apical sealing was evaluated using dye penetration test by immersing the apical part in 0.5 ml of 2% Methylene blue solution for 72 hours. Then the nail varnish was removed, the roots were sectioned longitudinally in a labio-lingual direction, and then examined under stereomicroscope to determine the depth of dye penetration into the RC. Results were tabulated and statistically analyzed.
The results showed that in this study, there was statistically significant difference between the tested sealers regarding their apical sealing ability. CeraSeal showed the highest apical microleakage amongst the tested sealers.
For bond strength evaluation, thirty-three extracted single rooted sound anterior teeth were decoronated, prepared, and obturated with one of the three sealers (n = 8). After complete setting, dentin discs 2 mm in thickness with the filling material in their core were obtained from each root third (at 3 mm, 6 mm, and 9 mm from the apex)
Push-out test was done using universal testing machine to measure the maximum load required to displace the material and a stereomicroscope to determine the mode of bond failure. Results were tabulated and statistically analyzed.
The results showed that in this study, there was statistically significant difference between the tested sealers’s bonding strength with the CeraSeal showing least bonding to dentin in all root sections except at the coronal sections. Bond strength in all sealers was highest apically and least coronally with statistically significant differences between the values measured at different root sections.
The major failure mode found for each sealer was Adhesive for MTA Fillapex group, while mixed failure was predominant for CeraSeal and Adseal groups. Each sealer presented different modes of failures in different root sections.
B. Conclusion
Based on the present results, within the circumstances of this in-vitro study, it can be concluded that:
1- Resin-based sealers outperformed CSBSs in terms of solubility, sealing and bonding to RC dentin.
2- CSBSs’ solubility violated the set range by the ISO specification NO. 6876:2012 (3% mass fraction).