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Several calcium silicate cement (CSC) types with improved handling properties have been developed lately for root-end filling applications. While sealing ability is important, a high biocompatibility and antimicrobial effects are critical. This study aimed to conduct a comparative evaluation of the antimicrobial efficacy and sustained antibacterial effectiveness against Enterococcus faecalis (E. faecalis) of commercially available CSCs mixed with distilled water (DW) and chlorhexidine (CHX). Various products, viz., ProRoot mixed with DW (PRW) or with CHX (PRC), Endocem mixed with DW (EW) or with CHX (EC), and Endocem premixed (EP) syringe type, were used. While antibacterial activity against E. faecalis was evaluated using a direct contact method, the specimens were stored in a shaking incubator for 30 d for antibacterial sustainability. The cytotoxicity was evaluated using a cell counting kit-8 assay in human periodontal ligament stem cells. The antibacterial activities of EP, EW, and EC were greater than those of PRC and PRW (p < 0.05). The antibacterial sustainability of EP was the highest without cytotoxicity for up to 30 days (p < 0.05). In conclusion, the pre-mixed injectable type EP was most effective in terms of antibacterial activity and sustained antibacterial effectiveness without cytotoxicity.

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In this in vitro study, we assessed the antibacterial efficacy of four endodontic sealers-resin AH26, EndoRez, calcium hydroxide (Apexit), and pure zinc oxide-against Enterococcus faecalis. The agar diffusion test was employed to evaluate the antibacterial efficacy of the sealers in vitro, with distilled water serving as a control. The sealers were prepared following the manufacturer's instructions and placed in wells of 50 agar plates, each inoculated with 15 samples of Kocuria rhizophila and Staphylococcus aureus. Inhibition zones were assessed after 72, 120, and 168 hours of anaerobic incubation at 37°C for 196 hours. Kruskal-Wallis and Friedman tests were used for data analysis. Positive control plates exhibited bacterial growth in all specified periods. AH26 demonstrated significantly higher antibacterial effectiveness against both bacterium types compared to the other sealers (P<0.01). Pure zinc oxide exhibited moderate antibacterial activity, while Apexit and EndoRez showed the lowest activity against S. aureus and no activity against K. rhizophila. AH26 had the highest antibacterial effect, and EndoRez had the lowest (P<0.05). In terms of inhibiting bacterial growth, the effectiveness of root canal sealers was ranked as follows: AH26 > Pure Zinc Oxide >Apexit/EndoRez.

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PURPOSE: This study aimed to compare the antibacterial effectiveness of passive ultrasonic irrigation (PUI), Er,Cr:YSGG laser (WTL), and photon-induced photoacoustic streaming (PIPS) using an Er:YAG laser against Enterococcus faecalis biofilms in the apical third of root canals. METHODS: Root canals of 70 single-rooted human teeth were instrumented and infected with E. faecalis for 3 weeks to form biofilms. The samples were randomly divided into five groups as follows: (i) PUI + 3% NaOCl (n = 16); (ii) Er,Cr:YSGG laser (n = 16); (iii) PIPS + 3% NaOCl (n = 16); (iv) positive control group (n = 10); and (v) negative control group (n = 10). The bacterial content in the root canal was sampled using (a) the paper-point sampling method before (S1) and after (S2) treatment and (b) pulverising the apical 5 mm of the root. The number of bacteria recovered from each group was counted as colony-forming units (CFUs). The amount of reduction between the groups was compared with the Kruskal-Wallis test and post-test Dunn's multiple comparisons tests. The significance level was set at 5% (p < 0.05). RESULTS: The samples from the paper-point sampling method showed that the amount of bacteria before (S1) and after treatment (S2) was significantly different between PIPS and WTL, as well as between the PUI and WTL groups. In contrast, no significant difference was found between the PIPS and PUI groups. From the pulverised samples, the results indicated no significant difference among all experimental groups in the amount of bacterial reduction in the apical 5 mm of the root. CONCLUSIONS: PUI and PIPS showed a significantly greater reduction in bacterial content within the main root canal compared with the WTL. There was no difference among all experimental groups in the apical third of the root.

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Biotransformation of selenite by microorganisms is an effective detoxification (in cases of dissimilatory reduction, e.g., to Se0) and assimilation process (when Se is assimilated by cells). However, the current knowledge of the molecular mechanism of selenite reduction remains limited. In this study, a selenite-resistant bacterium was isolated and identified as Proteus sp. YS02. Strain YS02 reduced 93.2% of 5.0 mM selenite to selenium nanoparticles (SeNPs) within 24 h, and the produced SeNPs were spherical and localized intracellularly or extracellularly, with an average dimension of 140 ± 43 nm. The morphology and composition of the isolated and purified SeNPs were characterized using dynamic light scattering (DLS), scanning electron microscopy (SEM) with energy-dispersive X-ray (EDX) spectrometry, and Fourier transform infrared (FTIR) spectroscopy. FTIR spectroscopy indicated the presence of proteins, polysaccharides, and lipids on the surface of the isolated SeNPs. Furthermore, the SeNPs showed excellent antimicrobial activity against several Gram-positive and Gram-negative pathogenic bacteria. Comparative transcriptome analysis was performed to elucidate the selenite reduction mechanism and biosynthesis of SeNPs. It is revealed that 197 genes were significantly upregulated, and 276 genes were significantly downregulated under selenite treatment. Gene ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses revealed that genes associated with ABC transporters, sulfur metabolism, pentose phosphate pathway (PPP), and pyruvate dehydrogenase were significantly enhanced, indicating selenite is reduced by sulfite reductase with PPP and pyruvate dehydrogenase supplying reducing equivalents and energy. This work suggests numerous genes are involved in the response to selenite stress, providing new insights into the molecular mechanisms of selenite bioreduction with the formation of SeNPs.

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AIM: To evaluate the antibacterial effect of sonic- and ultrasonic-activated irrigation on bacterial reduction of a dual-species biofilm in root canals compared to nonactivated irrigation in a laboratory study. METHODOLOGY: Two hundred and forty extracted human single-rooted maxillary anterior teeth were divided into two main groups (G, n = 120) according to the initial preparation size of the root canal (G1: size 25, 0.06 taper, G2: size 40, 0.06 taper). Root canals were inoculated with Enterococcus faecalis and Streptococcus oralis. After 5 days, G1 received combined instrumentation (up to size 40, 0.06 taper) and irrigation/activation, whereas G2 received solely irrigation/activation protocols. In both groups, irrigation was performed with sodium hypochlorite (NaOCl 1%) or physiological saline (NaCl 0.9%), using nonactivated syringe irrigation, sonic activation (2 x 30 s) or ultrasonic activation (2 x 30 s). Logarithmic reduction factors (LRFs) of colony-forming units were analysed separately for dentine-adherent and planktonic bacteria immediately after irrigation/activation protocols (time-point 1) or after 5 days of further incubation (time-point 2) by analysis of variance (anova) and post hoc tests (Tukey's HSD, t-test). The significance level was set at 0.05. RESULTS: In G1 subgroups (combined instrumentation with irrigation/activation), LRFs were significantly affected by the applied irrigation solution (p < .0001), but not by the activation method (p > .05; anova). In G2 subgroups (solely irrigation/activation), both, irrigant solution and activation, significantly affected LRFs (p < .0001, anova). Sonic activation resulted in significantly higher LRFs than ultrasonic activation (p < .0001) which had significantly greater reductions than nonactivated irrigation (p < .05; Tukey's HSD). At T2, strong bacterial regrowth was observed in all groups; however, a significant bacterial reduction was detected for factors instrumentation, irrigant solution and activation (p < .0001; anova). Similar LRFs were found for dentine-adherent and planktonic bacterial cells in all groups (r = 0.91 at T1, r = 0.8 at T2). CONCLUSIONS: In this laboratory study on extracted maxillary anterior teeth high-frequency sonic activation resulted in a greater bacterial reduction compared to ultrasonic activation in groups receiving solely irrigation/activation protocols; however, irrigation using NaOCl and ultrasonic activation also contributed significantly to bacterial reduction compared to the control groups.

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Objetivos: Este estudio tiene como objetivo la comparación de la eficacia antibacteriana sobre el Enterococcus faecalis, de tres cementos selladores de obturación utilizados en la terapia endodóntica, determinada mediante la medición del tamaño del halo inhibitorio. Material y métodos: se realizó un estudio comparativo in vitro, en el cual se utilizó el método de difusión en el agar de Müller- Hinton. Se calculó una muestra de 10 replicaciones por cemento haciendo un total de 30 unidades de estudio (mediante el programa G Power 3.1). Los datos del halo inhibitorio fueron medidos en milímetros después de 24 horas de incubación, a una temperatura de 37°C, los resultados obtenidos se anotaron en una ficha elaborada por el autor, para posteriormente procesarlos mediante el análisis estadístico de Shapiro-Wilk, Kruskal-Wallis y U de Mann Whitney. Resultados: El sellador a base de resina epóxica (TOPSEAL) presentó un halo de inhibición de 7,7 mm, el sellador a base de hidróxido de calcio (SEALAPEX) provocó un halo inhibitorio de 6,0 mm y el sellador a base de óxido de zinc y eugenol (GROSSFAR) presentó un halo de inhibición de 8,4 mm, siendo el de mayor eficacia de los tres selladores utilizados en este estudio. Conclusiones: Con este estudio se llegó a la conclusión que los selladores estudiados no son iguales entre si con respecto a su eficacia antibacteriana contra el Enterococcus faecalis.

Objectives: The aim of this study was the comparison of antibacterial effectiveness of three endodontic sealers, used in endodontic therapy. The antibacterial effectiveness of sealers was determinate by measuring the inhibitory halo against Enterococcus faecalis. Material and methods: A comparative in vitro study was done; the method of agar diffusion of Müller- Hinton was used. A sample of 10 replications for each sealer was estimated with the help the program (G Power 3.1) the total of sample was the 30 units of study. The data of inhibitory halo was measured in millimeters after 24 hours, incubated a temperature of 37°C, the results was registered in a format developed by the author, later the results were processed by statistical analysis Shapiro-Wilk, Kruskal-Wallis and U de Mann Whitney. Results: The resin- based sealer (TOPSEAL) showed an inhibitory halo of 7.7 mm; the hydroxide of calcium - based sealer (SEALAPEX) was of 6.0 mm whereas the oxide of zinc and eugenol - based sealer showed an inhibitory halo of 8.4 mm, this inhibitory halo was the biggest in this study. Conclusions: This study concluded that the sealers used in this study are not equal in their antibacterial effectiveness against Enterococcus faecalis.

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AIM: To compare the characteristics of bioceramic endodontic sealer Endosequence BC sealer with those of AH Plus sealer. METHODOLOGY: Cytotoxicity and genotoxicity were analysed on human gingival fibroblasts submitted to cell culture medium conditioned by sealers using the MTT reduction assay and micronucleus formation test (MNT), respectively. Cells grown on fresh medium served as controls. Cell viabilities were measured at 1, 3, 5 and 7 days. The antibacterial activity was analysed on an Enterococcus faecalis strain (ATCC 29212) using both on agar diffusion test (ADT) and a direct contact test (DCT). The inhibition zones in ADT were measured after 48 h and the colony-forming units counting in the DCT after 1, 24, 72 and 168 h. Data were compared by anova and Tukey's test and MNT by Fisher's exact test (P < 0.05). RESULTS: Cultures submitted to Endosequence BC sealer had a significantly higher number of viable cells (P < 0.01) and less micronucleus formation (P < 0.05) than AH Plus sealer. Endosequence BC sealer exhibited significantly smaller inhibition zones (6.00 ± 0.03 mm) than AH Plus sealer (10.31 ± 0.21 mm) (P < 0.05). Moreover, Endosequence BC sealer had significantly smaller antibacterial activity than AH Plus sealer up to 1 h of direct contact (P < 0.05). On other exposure times, both materials had similar antibacterial effectiveness (P > 0.05). CONCLUSIONS: Bioceramic-based sealer had less cytotoxicity and genotoxicity and similar antibacterial effect against E. faecalis in comparison with AH Plus sealer.