Assessment of Root Canal Sealers Loaded with Drug-Silica Co- Assembled Particles using In Vitro Tooth Model.

Abstract

OBJECTIVES\nTo assess the antimicrobial activity of root canal sealers modified with novel highlyloaded antimicrobial drug-silica co-assembled particles (DSPs) on Enterococcus faecalis-infected root canal dentin.\n\n\nMETHODS\nDSPs were synthesized through co-assembly of silica and Octenidine dihydrochloride (OCT) surfactant drug (35%w/w OCT). DSPs (1% wt of the total mass of the sealer) were mixed homogenously with either epoxy-resin sealer (AH) (AH Plus®, Dentsply) or calcium silicatebased sealer (BC) (Bioceramic SealerTM, EndoSequence). To assess the antimicrobial activity of DSP loaded sealers, apical third of single rooted teeth were obtained, and infected with E. faecalis for 3 weeks, followed by the application of experimental (DSPs-loaded) sealers or corresponding controls for up to 28 days. Microbiological analysis, and laser scanning confocal and scanning electron microscopy were used to determine Colony Forming Unit (CFU)/mL, percentage of live bacteria, and intratubular bacterial and sealer penetrations. Factorial ANOVA and Tukey s post hock tests were used to assess the antimicrobial effect of DSPs on different sealers.\n\n\nRESULTS\nAll experimental groups showed significant reductions in CFU at all time points compared to positive controls (P<0.05). The addition of DSPs to BC sealer significantly reduced the CFU (2.11±0.13, 2.22±0.19 and 2.25±0.17 at 1, 7 and 28 days respectively) when compared to the unmodified sealer (3.21±0.11, 4.3±0.15 and 4.2±0.2 at 0, 7 and 28 days. DSPs enhanced antimicrobial performance of AH only at 1 day (4.21± 0.17 vs. 5.19±0.12, P<0.05). AH and AH+DSP showed higher bacterial viability compared to BC sealer and BC+DSP at all incubation periods (P<0.05).\n\n\nCONCLUSIONS\nLoading endodontic sealers with DSPs had a material-dependent effect on the antimicrobial properties and could reduce the incidence of secondary infections.