الفهرس 
REVIEW OF LITERATUREOnly 14 pages are availabe for public view
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Abstract
The aim of the present study is to evaluate a new Biosilicate sealer in terms of its Physical properties (pH, Radiopacity, Setting time & Solubility), Bioactivity, Bond strength; Sealing ability & Cytotoxicity.
Materials & Methods:
Eighty discs (Forty each sealer) were subdivided into 4 groups for evaluation of pH, radiopacity, setting time and solubility according to the ISO standards-6876 and the ASTM C266-03. Twenty teeth (Ten teeth each sealer) were decoronated, roots were sliced into discs, their lumens were prepared and filled with sealers; the discs were stored in a phosphate buffered saline to be evaluated under SEM for Bioactivity. Forty teeth were decoronated, instrumented, dried and obturated using lateral compaction technique (Ten teeth each sealer) for evaluation of push-out bond strength and sealing ability using the linear dye penetration method. Twenty discs (Ten each sealer) were prepared for evaluation of cytotoxicity using the MTT assay; at 24 and 72 hours. Data was subjected to statistical analysis.
Results:
Both sealers have shown an alkalizing pH at all observation times, with the BioRoot RCS showing a statistically significantly higher mean value than MTA Fillapex. Both sealers were radiopaque, however BioRoot RCS showed a statistically significantly higher mean radiopacity value compared to MTA Fillapex. MTA Fillapex has mean initial and final setting times statistically significantly longer than BioRoot RCs. A lower percentage weight loss was recorded by MTA Fillapex however the mean difference between both sealers was not statistically significant. BioRoot RCS recorded a greater mean value of the interfacial layer thickness, however the difference between both sealers was non significant. MTA Fillapex showed a greater mean value for the Ca/P ratio, with a non significant difference between both groups. MTA Fillapex displayed a greater mean bond strength value, in the middle and apical thirds; while BioRoot RCS showed a greater value in the coronal third only, the difference between the two sealers was not statistically significant. A greater mean value for linear dye penetration was recorded in MTA Fillapex group with no statistical difference found between both sealers. Both sealers showed a statistically significant reduction in their cytotoxicity over different observation times (24 & 72 hours).
Conclusions:
Under the limitations of the present study, it can be concluded that:
1. pH and Radiopacity of both sealers conform with the ISO standards 6876/2001 and the ANSI/ADA specifications.
2. Setting time and solubility of both sealers did not conform to the ISO standards 6876/2001 and the ANSI/ADA specifications.
3. Both sealers were comparable as regard to their sealing ability & their tendency to deposit bioactive precipitates.
4. Both sealers did not provide adequate bonding at different canal levels.
5. Both sealers showed a decrease in their cytotoxicity with time.
Recommendations:
1. Further lab research work is needed for biosilicate based root canal sealers in order to improve its setting time & reduce its solubility.
2. Additional studies are needed to evaluate the antimicrobial effect of BioRoot RCS due to its high initial pH.
3. Evaluation of the bioactivity of BioRoot RCS at extended time intervals.
4. Analysis of the storage solutions for bioactivity and solubility tests; regarding the dynamic interaction of the material with the surrounding environment (ion leaching, water sorption & solubility at extended time intervals) is essential.
5. Tailoring of specific standardized methodologies regarding biosilicate sealers, as the current ISO standards available are not satisfactory for bioactive materials.
6. Cytotoxicity of both sealers must be tested at extended evaluation times.