| Summary: | The present study aimed to fabricate and characterise novel algin-incorporated
bioactive glass 58S calcium-silicate root canal sealer (Bio-G) and evaluate its effect
on the dislodgement resistance and dentinal tubule penetration to root dentinal walls
in comparison to commercially available bioceramic-based sealers (BioRoot RCS and
iRoot SP). Three groups of bioactive glass (BG) 58S powders were synthesised using
sol-gel method and characterised using SEM, HRTEM and FTIR for optimisation:
BG-1 (no ammonia), BG-2 (3 ml of ammonia), and BG-3 (5 ml of ammonia).
Optimised BG-3 was used to fabricate the powder form of experimental Bio-G sealer
with the addition of calcium silicate, zirconia dioxide, calcium carbonate and alginic
acid powder. Meanwhile, the liquid form composed of 5% calcium chloride solution.
The experimental 0-5% algin Bio-G sealers were then compared with BioRoot RCS
and iRoot SP. Standardised disc specimens of mixed sealer materials (n=5 per group)
were prepared and placed in an incubator to allow setting before characterising under
SEM, HRTEM, EDS, FTIR and XRD. Next, one-hundred-and-seventy-six mandibular
premolars were randomly assigned (n=16 per group): control, gutta-percha + 0-5%
algin Bio-G, gutta-percha + BioRoot RCS, and gutta-percha + iRoot SP groups, with
the exclusion of the control group in adhesive pattern and dentinal tubule penetration
tests. They were instrumented, obturated and placed in an incubator for 72 hours to
allow sealer set. For the dentinal tubule penetration test, sealers were mixed with 0.1%
of rhodamine B dye. Subsequently, teeth were cut into a 1-mm-thick cross-section at 5-mm and 10-mm levels from the root apex, respectively. Push-out bond strength,
adhesive pattern and dentinal tubule penetration tests were performed. Experimental
Bio-G sealer revealed irregular micro-sized particles with a higher content of oxygen,
silicon, and calcium, as well as trace of aluminium and chloride. Meanwhile, FTIR
and XRD findings suggested that all sealers predominantly contained calcium silicate
hydrate, calcium carbonate, and zirconium dioxide, while calcium aluminium silicate
oxide was detected in 0-5% algin Bio-G. 5% algin Bio-G showed the highest mean
push-out bond strength (p<0.05) with more favourable adhesion pattern, while iRoot
SP showed the greatest sealer penetration (p<0.05). In addition, no significant
association was noted between the dislodgement resistance and dentinal tubule
penetration (p>0.05). In conclusion, the present novel Bio-G sealer demonstrated
desirable particle size distribution and acceptable degree of purity. Algin-incorporated
Bio-G showed favourable adhesive pattern with comparable dislodgement resistance
and dentinal tubule penetration values to commercialised bioceramic-based sealers.
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