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Objectives: Antibacterial activity against endodontic pathogens is a desirable feature for root canal sealers. The objective of this study was to compare the antibacterial effect of three resin-based endodontic sealers (AH26, Adseal, and Beta RCS) against Enterococcus faecalis in vitro. Materials and Methods: The antibacterial properties of the sealers were assessed against E. faecalis using agar diffusion test (ADT) for fresh state (N=10) and direct contact test (DCT) for freshly-mixed and set states of the materials (N=10). In ADT, the diameter of the zones of inhibition was measured after 24h of contact. In DCT, the colony-forming units of the bacteria were counted after 30 minutes and 180 minutes of exposure. The results were analyzed with two-way ANOVA and independent sample t-test. P<0.05 was considered significant. Results: Regarding DCT results, all test materials indicated an antibacterial effect, both in freshly-mixed and set states. The highest antibacterial effect was related to Adseal, whereas the lowest was observed in Beta RCS. There was a significant difference between all study groups (different sealers, setting states, and contact times; P<0.001), except for freshly-mixed AH26 and Adseal at 180 minutes (P>0.05). According to ADT, AH26 and Adseal represented the widest and the smallest inhibition zones, respectively (P<0.001). Conclusion: Within the limitations of this in vitro study, AH26, Adseal, and Beta RCS showed antibacterial effects against E. faecalis in both freshly-mixed and set states. The antibacterial effect increased over time in all of the studied sealers., Competing Interests: None declared., (Copyright © 2024 The Authors. Published by Tehran University of Medical Sciences.)

Objectives: This study aimed to assess the effect of addition of fluorohydroxyapatite (FHI) on biological and physical properties of mineral trioxide aggregate (MTA) Angelus., Materials and Methods: In this in vitro, experimental study, nano-FHI powder was first synthesized, and the morphology and chemical structure of particles were evaluated by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). Three groups were evaluated in this study: MTA Angelus, MTA modified with 10% FHA, and MTA modified with 15% FHA. After mixing, the materials were applied to ring molds (10 mm diameter, 1 mm height), and the setting time of the three groups was evaluated according to ISO6876 and ASTMC266-03 with a Gillmore needle. The pH was measured using a pH meter at 24 and 48 hours and 7 days after mixing. The cytotoxicity of the materials was assessed in freshly mixed form and after 1 and 7 days using the methyl thiazolyl tetrazolium (MTT) assay according to ISO10993-5. Data were analyzed by one-way and repeated measures ANOVA and Tukey's test (alpha = 0.05)., Results: The addition of FHA to MTA significantly decreased the initial setting time ( P  < 0.05) and had no significant effect on cell viability (compared with pure MTA Angelus) at 1 and 7 days. However, modified MTA groups in freshly mixed form showed significantly lower cell viability ( P  < 0.05). The pH remained alkaline at all time points., Conclusion: Addition of 15% FHA to MTA Angelus decreased its setting time with no adverse effect on cell viability (except for fresh form) or pH., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2023 Behnam Bolhari et al.)

Objectives: This in-vitro study aimed to evaluate the physical properties of three resin-based root canal sealers, including BETA-RCS, AH26, and Adseal. Materials and Methods: Flowability, film-thickness, solubility, and radiopacity of BETA-RCS, AH26, and Adseal sealers were evaluated according to ISO 6876/2012 specifications. Three samples of each sealer were used to test each of the properties. Results: The results revealed that the flow rate (mm) of BETA-RCS, Adseal, and AH26 were 23.06±1.58, 22.5±4.23, and 21.85±1.71, respectively. Film-thickness values (µm) for BETA-RCS, Adseal, and AH26 sealers were 52.33±2.51, 18.66±0.57, and 52±2, respectively. No significant difference was observed regarding film-thickness between AH26 and BETA-RCS (P>0.05), while Adseal showed significantly lower film-thickness (P˂0.05). The highest and lowest solubility were related to BETA-RCS and Adseal, respectively. However, all sealers had acceptable solubility and radiopacity. Conclusion: The findings of the current study suggested that all three root canal sealers including BETA-RCS, AH26, and Adseal had similar properties based on ISO 6876 standard criteria. As such, they could be viable choices for facilitating effective root canal procedures. Further long-term clinical studies are warranted to assess their performance and success rates in actual endodontic cases., Competing Interests: None declared., (Copyright © 2023 The Authors. Published by Tehran University of Medical Sciences.)

Enterococcus faecalis is the dominant microorganism in chronic apical periodontitis. It is more resistant to local antiseptic agents than other endodontic microorganisms. Currently, mineral trioxide aggregate (MTA) is considered as an ideal material in many endodontic procedures. Some studies have shown that MTA has good antibacterial activity against E. faecalis . However, some studies have investigated the effect of incorporating some materials into MTA on its antibacterial activity against E. faecalis . No study has evaluated the effect of incorporating fluorohydroxyapatite nanoparticles (nano-FHA) on the antimicrobial activity of MTA. Therefore, the present study evaluated the antimicrobial effect of MTA mixed with nano-FHA on E. faecalis in vitro. The study was carried out on 18 samples in three groups: pure MTA, MTA mixed with 10 wt% of nano-FHA, and MTA mixed with 15 wt% of nan-FHA. The effect of nano-FHA on the antibacterial activity of MTA on E. faecalis was evaluated by evaluating the growth inhibition zone around each sample. The antimicrobial effect of samples on inhibiting E. faecalis biofilm formation and inhibiting microbial growth of E. faecalis in the planktonic phase was evaluated by disk agar diffusion (DAD), biofilm inhibition assay (BIA), and direct contact assay (DCA) tests, respectively. All the above tests were analyzed after 24 and 72 hours. Factorial designs were used for statistical analyses. Tukey tests were used for two-by-two comparisons. All the statistical analyses were carried out with SPSS 26. DAD results showed no formation of the growth inhibition zone in all the samples after 24 and 72 hours. The microbial colony counts in the BIA and DCA tests in the groups modified with FHA nanoparticles were significantly lower than the pure MTA group ( P < 0.05). The microbial colony counts increased in all the groups over time ( P < 0.05). Incorporating nano-FHA into MTA improved the antimicrobial activity of MTA against E. faecalis compared to pure MTA. The highest antimicrobial activity was achieved after incorporating 15 wt% of nano-FHA into MTA at the 72-hour interval., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2021 Behnam Bolhari et al.)