Novel bioactive nanospheres show effective antibacterial effect against multiple endodontic pathogens.

Aim: The current study evaluated the antibacterial activity of a newly developed quaternary ammonium polymethacrylate (QAPM)-containing bioactive glasses (BGs) via a two-step method by our group, namely BGs-HAEMB, and explored its cytotoxicity and biocompatibility. Methods: The antibacterial effects of the BGs-HAEMB against planktonic bacteria, bacterial biofilm formation, and experimental root canal biofilms of persistent pathogens (Enterococcus faecalis, Streptococcus sanguis and Porphyromonas endodontalis) associated with endodontic infection were evaluated in vitro by agar diffusion tests, direct contact tests and live/dead staining. The cytotoxicity and biocompatibility of BGs-HAEMB were evaluated by CCK-8 assays in vitro and a skin implantation model in vivo. Results: Compared to three clinically used endodontic sealers (Endofill, AH Plus, and iRoot SP), BGs-HAEMB exhibited the relatively strongest antibacterial effect against E. faecalis, S. sanguis and P. endodontalis after sitting for 14 and 28 days (P < 0.01). SEM images and CLSM images also showed that for each tested bacteria, BGs-HAEMB killed the most microorganism among all the experimental groups, regardless of treatment for 7 days or 28 days (P < 0.05). Besides, the BGs-HAEMB-treated groups showed a relatively low cytotoxicity (RGRs ranging from 88.6% to 102.9%) after 1, 3, and 7 days of exposure. Meanwhile, after 28 days of implantation, the inflammatory grade in BGs-HAEMB treated group was assessed as Grade I, in which the average numbers of inflammatory cells (6.7 ± 2.1) were less than 25. Conclusions: BGs-HAEMB exerted a long-term and stable antibacterial effect. The remarkable biocompatibility of BGs-HAEMB in vitro and in vivo confirmed its possible clinical application as a potential alternative in the development of the next generation of endodontic sealers.

Intravenous leiomyoma of the uterus extending to the pulmonary artery: A case report.

BACKGROUND: Uterine intravenous leiomyomatosis is defined as leiomyoma tissue invading the vein outside the leiomyoma. Reports of extension to the right pulmonary artery are relatively rare. CASE SUMMARY: We describe a 31-year-old woman with a benign leiomyoma that extended into the right ventricular lumen, causing mechanical obstruction and corresponding clinical symptoms. Tumors located in the pulmonary artery can cause pulmonary artery obstruction. After diagnosis, surgical treatment should be performed as soon as possible. CONCLUSION: In this case, the uterine leiomyoma extended to the right pulmonary system, which is clinically rare.

Antagonistic interaction between two key endodontic pathogens Enterococcus faecalis and Fusobacterium nucleatum.

Background: Endodontic infections are known to be caused by pathogenic bacteria. Numerous previous studies found that both Fusobacterium nucleatum and Enterococcus faecalis are associated with endodontic infections, with Fusobacterium nucleatum more abundant in primary infection while Enterococcus faecalis more abundant in secondary infection. Little is known about the potential interactions between different endodontic pathogens. Objective: This study aims to investigate the potential interaction between F. nucleatum and E. faecalis via phenotypical and genetic approaches. Methods: Physical and physiological interactions of F. nucleatum and E. faecalis under both planktonic and biofilm conditions were measured with co-aggregation and competition assays. The mechanisms behind these interactions were revealed with genetic screening and biochemical measurements. Results: E. faecalis was found to physically bind to F. nucleatum under both in vitro planktonic and biofilm conditions, and this interaction requires F. nucleatum fap2, a galactose-inhibitable adhesin-encoding gene. Under our experimental conditions, E. faecalis exhibits a strong killing ability against F. nucleatum by generating an acidic micro-environment and producing hydrogen peroxide (H2O2). Finally, the binding and killing capacities of E. faecalis were found to be necessary to invade and dominate a pre-established in vitro F. nucleatum biofilm. Conclusions: This study reveals multifaceted mechanisms underlying the physical binding and antagonistic interaction between F. nucleatum and E. faecalis, which could play a potential role in the shift of microbial composition in primary and secondary endodontic infections.

Bioactive mono-dispersed nanospheres with long-term antibacterial effects for endodontic sealing.

Endodontic sealers with antibacterial capability play an important role in preventing reinfection of an endodontically treated root canal and improving the long-term success of root canal treatment. However, current endodontic sealers rapidly lose their antibacterial properties after fixation. In this work, we designed and synthesized quaternized mono-dispersed bioactive nanospheres as a potential substrate for the development of a long-term antibacterial endodontic sealer with excellent cytocompatibility and biocompatibility. First, mono-dispersed silica-based bioactive glass nanospheres (SBG-NS) were prepared via a modified sol-gel process. Next, a series of quaternary ammonium methacrylate salts (QAMs) with broad antibacterial spectra were synthesized and grafted onto the surfaces of the SBG-NS via a two-step coupling approach. The antibacterial effect of the quaternary ammonium polymethacrylate (QAPM)-containing SBG-NS (SBG-QAPM) against persistent microorganisms associated with infected root canals was evaluated using a direct contact test. Evaluations of the SBG-QAPM cytocompatibility and biocompatibility were performed using LIVE/DEAD staining, 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl-2, 5-tetrazoliumbromide (MTT) assay, and a calvarial implantation model. The results showed that the SBG-QAPMs had the strongest long-term antibacterial effect against the Enterococcus faecalis, Streptococcus mutans, and Streptococcus sanguis during the study period, the best cytocompatibility, and the lowest systemic inflammation compared to three commercial products: ProRoot MTA, Endomethasone C, and AH Plus. In addition, the SBG-QAPMs showed excellent stability in aqueous solution. This work indicates that the SBG-QAPMs are promising substrates for the development of long-term antibacterial endodontic sealers.

Bactericidal Effect of Er:YAG Laser-Activated Sodium Hypochlorite Irrigation Against Biofilms of Enterococcus faecalis Isolate from Canal of Root-Filled Teeth with Periapical Lesions.

OBJECTIVE: This study was to evaluate the bactericidal effect of Er:YAG laser-activated sodium hypochlorite irrigation (Er:YAG + NaOCl) on biofilms of Enterococcus faecalis clinical isolate. BACKGROUND DATA: It was reported that Er:YAG + NaOCl had effective bactericidal effect on laboratory-adapted E. faecalis strain, while no study has reported its effect on the clinical isolate. METHODS: Eighteen E. faecalis strains were isolated from 39 root-filled teeth with periapical lesions, and their biofilm formation abilities were evaluated using the crystal violet staining method. Extracted human root canals were prepared to a 40#/.04 K3 instrument and contaminated with the E. faecalis isolate that presented the strongest biofilm formation ability for 4 weeks. The infected canals then received treatments of syringe irrigation with normal saline (NS) or NaOCl, ultrasonic activated irrigations US + NS and US + NaOCl, and Er:YAG laser-activated irrigations Er:YAG + NS and Er:YAG + NaOCl. The root canals were examined using scanning electron microscopy (SEM). The bacterial reductions were evaluated using the cell count method. RESULTS: SEM results showed that biofilm-like structures formed on the root canal walls after 4-week bacterial incubation. Er:YAG + NaOCl completely removed the E. faecalis biofilm from the root canal wall and made it the cleanest and most smooth surface among the treatment groups. Bacterial reductions in the treatment groups were presented in a descending order of Er:YAG + NaOCl (98.8%), US + NaOCl (98.6%) > NaOCl (94.0%) > Er:YAG + NS (91.9%) > US + NS (78.1%) > NS (51.1%) (p < 0.05). CONCLUSIONS: The Er:YAG + NaOCl showed an effective bactericidal effect on biofilms of E. faecalis isolate, which may be considered an effective protocol for root canal treatment.

Erbium:Yttrium Aluminum Garnet Laser-Activated Sodium Hypochlorite Irrigation: A Promising Procedure for Minimally Invasive Endodontics.

OBJECTIVE: This study was to evaluate the potential of Erbium:Yttrium Aluminum Garnet laser-activated sodium hypochlorite irrigation (Er:YAG + NaOCl) for minimally invasive endodontics (MIE). BACKGROUND DATA: Er:YAG laser irradiation can dramatically enhance the penetration of NaOCl, which may be a promising protocol for MIE. METHODS: Extracted human teeth were contaminated with Enterococcus faecalis for 4 weeks. The infected canals were then shaped to different apical terminal working widths (ATWW, 15#/0.04, 20#/0.04, 25#/0.04, 30#/0.04, and 40#/0.04) and treated with either Er:YAG + NaOCl (0.3 W, 20 sec) or NaOCl alone. Then, the ATWW were fixed at 15#/0.04, and the canals were treated with Er:YAG + NaOCl at 0.3 W for 40 and 60 sec, or at 0.5 and 1.0 W for 20 sec. Finally, bacterial reductions were evaluated using the cell count method. RESULTS: Er:YAG + NaOCl showed a higher disinfection efficacy at each ATWW compared with NaOCl alone (p < 0.001). The maximum bacterial reduction was 99.9% for the 40#/Er:YAG + NaOCl group and 93.6% for the 40#/NaOCl group. To achieve similar disinfection efficacy, the Er:YAG + NaOCl group needed a smaller ATWW than the NaOCl group. At a fixed ATWW, increasing the output power of the Er:YAG laser was more effective than increasing the radiation time to improve the disinfection efficacy of Er:YAG + NaOCl. The 15#/Er:YAG + NaOCl group reached the maximum bacterial reduction of 99.2% when the Er:YAG laser was activated at 1.0 W for 20 sec. CONCLUSIONS: The 15#/Er:YAG + NaOCl with the Er:YAG laser irradiation at 1.0 W for 20 sec may be considered a promising procedure for MIE.