Spatial Position Regulation of Cu Single Atom Site Realizes Efficient Nanozyme Photocatalytic Bactericidal Activity.

Recently, single-atom nanozymes have made significant progress in the fields of sterilization and treatment, but their catalytic performance as substitutes for natural enzymes and drugs is far from satisfactory. Here, a method is reported to improve enzyme activity by adjusting the spatial position of a single-atom site on the nanoplatforms. Two types of Cu single-atom site nanozymes are synthesized in the interlayer (CuL /PHI) and in-plane (CuP /PHI) of poly (heptazine imide) (PHI) through different synthesis pathways. Experimental and theoretical analysis indicates that the interlayer position of PHI can effectively adjust the coordination number, coordination bond length, and electronic structure of Cu single atoms compared to the in-plane position, thereby promoting photoinduced electron migration and O2 activation, enabling effective generate reactive oxygen species (ROS). Under visible light irradiation, the photocatalytic bactericidal activity of CuL /PHI against aureus is ≈100%, achieving the same antibacterial effect as antibiotics, after 10 min of low-dose light exposure and 2 h of incubation.

Advanced and Readily-Available Wireless-Powered Blue-Light-Implant for Non-Invasive Peri-Implant Disinfection.

Non-invasive light-based antibacterial therapy has a good prospect in non-surgical treatment of peri-implant infections. However, its applications are severely limited by poor penetration of light into human tissues, leading to unsatisfying outcomes. Moreover, as an essential prerequisite for traditional light therapy, lasers can no longer meet the patients' needs for convenient treatment at any time. To break through the spatial and temporal limitations of traditional light therapy, a wireless-powered blue-light zirconia implant for readily available treatment of peri-implant infection is proposed. In space, complete irradiation to complex peri-implant structure is realized by the built-in wireless-powered light source, thus improving the efficacy. In time, wireless-powering allows timely and controllable anti-infection treatment. Blue micro-light emitting diodes are used as therapeutic light sources, which effectively kill peri-implant infection-related bacteria without exogenous photosensitive agents. Porphyromonas gingivalis biofilm on implant surface can be completely killed after 20 min irradiation in vitro. The bactericidal rate of peri-implant methicillin-resistant Staphylococcus aureus infection reaches 99.96 ± 0.03% under 30 min per day blue light exposure in vivo. Within the scope of this study, the treatment of peri-implant infection with blue-light implant has preliminary feasibility, giving a new approach to non-invasive treatment of deep oral infections, including peri-implant infections.

Response of genes related to iron and porphyrin transport in Porphyromonas gingivalis to blue light.

BACKGROUND: Antimicrobial blue light (aBL) kills a variety of bacteria, including Porphyromonas gingivalis. However, little is known about the transcriptomic response of P. gingivalis to aBL therapy. This study was designed to evaluate the selective cytotoxicity of aBL against P. gingivalis over human cells and to further investigate the genetic response of P. gingivalis to aBL at the transcriptome level. METHODS: Colony forming unit (CFU) testing, confocal laser scanning microscopy (CLSM), and scanning electron microscopy (SEM) were used to investigate the antimicrobial effectiveness of blue light against P. gingivalis. The temperatures of the irradiated targets were measured to prevent overheating. Multiple fluorescent probes were used to quantify reactive oxygen species (ROS) generation after blue-light irradiation. RNA sequencing (RNA-seq) was used to investigate the changes in global gene expression. Following the screening of target genes, real-time quantitative polymerase chain reaction (RT-qPCR) was performed to confirm the regulation of gene expression. RESULTS: A 405 nm aBL at 100 mW/cm2 significantly killed P. gingivalis within 5 min while sparing human gingival fibroblasts (HGFs). No obvious temperature changes were detected in the irradiated surface under our experimental conditions. RNA-seq showed that the transcription of multiple genes was regulated, and RT-qPCR revealed that the expression levels of the genes RgpA and RgpB, which may promote heme uptake, as well as the genes Ftn and FetB, which are related to iron homeostasis, were significantly upregulated. The expression levels of the FeoB-2 and HmuR genes, which are related to hydroxyl radical scavenging, were significantly downregulated. CONCLUSIONS: aBL strengthens the heme uptake and iron export gene pathways while reducing the ROS scavenging pathways in P. gingivalis, thus improving the accumulation of endogenous photosensitizers and enhancing oxidative damage to P. gingivalis.

Alteration of microbiota and immune response of mice gavaged with Klebsiella oxytoca.

Interactions between the microbiota and immune system play a vital role in the host homeostasis. Increasing studies have investigated environmental perturbations affecting the microbiota. However, studies also are needed to model how an organ-specific immune response affects the microbiota to understand the dynamic changes between the immune system and microbiota. We constructed a murine Klebsiella oxytoca infection model, in which mice were gavaged with K. oxytoca, and the microbiota and immune responses of both the digestive tract and respiratory tract were compared for 1-2 weeks after infection. Metagenomic and cytokine analysis of the samples displayed a delayed colonization of K. oxytoca, but an early immune response in the respiratory tract, as compared with that in the digestive tract, suggested niche-specific characteristics of bacterial colonization and the corresponding immune response. Furthermore, we constructed an interaction map of K. oxytoca in both the digestive tract and respiratory tract that furthers our understanding of the host-microbe biology in K. oxytoca-infected hosts.

Clinical Evaluation of 532-nm Green Laser on Dentin Hypersensitivity: A Randomized Double-Blind Clinical Trial.

Objective: The aim of this study was to evaluate the therapies of low-level green laser and chemical desensitizer in the treatment of dentin hypersensitivity (DH). Methods: Forty-eight patients with 96 sensitive teeth were invited to participate in this clinical trial and were randomly divided into three groups. One group was treated with low-level green laser, the second group was treated with desensitizer [sodium fluoride (NaF)], and the third group acted as the placebo group and was treated with distilled water and placebo laser. The wavelength of green laser was 532 nm and the irradiance was 15 J/cm2 per treatment site. Hypersensitivity was assessed by visual analogue scale (VAS) according to cold test and probing at baseline. Immediately, 2 weeks, and 3 months after the application of green laser, NaF, and placebo, the participants' sensitivity level was accessed by new VAS analysis. Results: Forty-five patients with 90 teeth (n = 15 patients/group; 30 teeth/group) were followed up for 2 weeks and 3 months after treatment. There were significant differences in VAS scores between the placebo group and intervention group (green laser group and NaF group; analysis of variance, p < 0.05) at all three time points. The mean pain scores in DH reduced significantly immediately after treatment in the green laser group and NaF group when stimulated by cold and probing, whereas no significant difference was observed with these two therapies after 2 weeks (p > 0.05). After 3 months, mean VAS scores of the NaF group were higher than those of the green laser group (p < 0.01). Conclusions: Therefore, the green laser displayed similar effectiveness as NaF in treatment of DH and could be a promising new therapy to reduce DH.

Effect of Photobiomodulation on Periodontal Ligament Cells Under Inflamed and Nutrient-Deficient Conditions Simulating Damaged Cells of Avulsed Teeth: An In Vitro Study.

Background: The prognosis of replanted teeth is depended on the vitality of periodontal ligament cells residual on the root surface. Photobiomodulation has photobiological effects that can promote cell vitality. The study aimed to explore the effect of photobiomodulation on the periodontal ligament cells under inflamed or starved conditions mimicking clinically damaged periodontal ligament cells of avulsed teeth and provide the adjuvant procedure for tooth replantation. Materials and methods: Normal, starved, or inflamed periodontal ligament cells were irradiated with an 808 nm laser at densities of 0, 1, 3, 5, or 10 J/cm2. The cell counting kit-8 (CCK-8) assay and scratch test were applied to determine the effects on the proliferation and migration of cells. Anti-inflammatory effects were assessed according to the mRNA expression of tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), and interleukin-6 (IL-6) measured by reverse-transcription polymerase chain reaction. Osteogenic capacity was evaluated by alkaline phosphatase (ALP) staining, ALP activity assay, Alizarin Red S staining, and ALP and osteocalcin (OCN) mRNA expression. Results: The CCK-8 assay and scratch test demonstrated that the 808 nm laser significantly promoted proliferation and migration of normal condition periodontal ligament cells at a density of 3 J/cm2 versus 5 J/cm2 under the starved and inflamed conditions. Moreover, the 808 nm laser had anti-inflammatory effects and promoted osteogenesis of periodontal ligament cells at 3 J/cm2 under normal conditions, while photobiomodulation at 5 J/cm2 upregulated the osteogenesis of periodontal ligament cells under starved and inflamed conditions. Conclusions: The photobiomodulation of 808 nm laser reduced inflammation and improved the proliferation, migration, and osteogenesis of normal, starved, and inflamed periodontal ligament cells. These effects required a higher energy density under starved or inflamed conditions compared with normal conditions. The photobiomodulation of 808 nm has a potential application in root surface treatment for replanted teeth.

Effects of Rose Bengal- and Methylene Blue-Mediated Potassium Iodide-Potentiated Photodynamic Therapy on Enterococcus faecalis: A Comparative Study.

BACKGROUND AND OBJECTIVES: This study was performed to compare the use of methylene blue (MB) and rose bengal (RB) in antimicrobial photodynamic therapy (PDT) targeting Enterococcus faecalis (E. faecalis) bacteria in planktonic and biofilm forms with potassium iodide (KI) potentiation. STUDY DESIGN/MATERIALS AND METHODS: E. faecalis bacteria in planktonic form were exposed to antimicrobial PDT protocols activating MB and RB, with or without KI potentiation, following laser irradiation with different exposure times, 60 mW/cm2 laser power, and different photosensitizer agent (PS)/potentiator concentrations to observe relationships among the variables. Two continuous-wave diode lasers were used for irradiation (red light: λ = 660 nm and green light: λ = 565 nm). The pre-irradiation time was 10 minutes. The vitality of E. faecalis biofilm was assessed by confocal laser scanning microscopy, and the morphology was determined by scanning electron microscopy. The effects on the proliferation of stem cells from the apical papilla (SCAPs) were analyzed by cell counting kit-8 assay. The staining effect of antimicrobial PDT on dentin slices was investigated. Statistical analysis using a one-way analysis of variance was done. RESULTS: KI-potentiated RB and MB antimicrobial PDT both effectively eradicated E. faecalis bacteria in planktonic and biofilm forms. The minimum bactericidal concentrations of PSs (±100 mM KI) were obtained through PDT on planktonic E. faecalis, and the optimal light parameters were 60 mW/cm2 , 6 J/cm2 for 100 seconds. KI-potentiated PDT effectively strengthened the ability to inhibit E. faecalis biofilm with 86.50 ± 5.78% for MB (P = 0.0015 < 0.01) and 91.50 ± 1.75% for RB (P = 0.0418 < 0.05) of bactericidal rate, with less toxicity for SCAPs (P < 0.001) and less staining. KI could reduce the staining induced by antimicrobial PDT on dentin slices. CONCLUSION: A combination of KI and antimicrobial PDT may be a useful alternative to conventional disinfection methods in endodontic treatment. MB and RB antimicrobial PDT at much lower concentrations with KI could hopefully achieve disinfection effects comparable with those of 1.5% NaClO while causing few adverse effects on SCAPs. KI helps to avoid staining problems associated with high concentrations of photosensitizer agents. Lasers Surg. Med. © 2020 Wiley Periodicals, LLC.

Antimicrobial Activity of an Implantable Wireless Blue Light-Emitting Diode Against Root Canal Biofilm In Vitro.

Objective: We developed an implantable wireless blue micro light-emitting diode (micro-LED) device and evaluated the utility of continuous antimicrobial blue light (aBL) irradiation emitted from this micro-LED for root canal disinfection. Methods: An implantable wireless blue micro-LED device (peak wavelength: 410 nm, maximum power: 15 mW) was developed to be placed in the root canal. Optical transmission of the device in human dentin tissue was simulated using Monte Carlo ray-tracing method. The bactericidal effect of low-level aBL on planktonic root canal infection-related bacteria [Enterococcus faecalis, methicillin-resistant Streptococcus aureus (MRSA), and Prevotella intermedia] was evaluated by colony counting. The biocompatibility of continuous low-level aBL exposure was evaluated by infrared thermal imaging and cell viability tests. Thirty extracted intact human single-rooted teeth were prepared and the root canals were infected with E. faecalis for 14 days to form biofilm. The infected root canals were randomly divided into three groups (n = 10), and treated with normal saline (group NS), calcium hydroxide (group CH), and micro-LED device (group aBL) for 3 and 7 days. The bactericidal effect of each group was evaluated by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). Results: Monte Carlo simulation showed that blue light irradiation of the micro-LED device decreased exponentially with the light transmission distance through human dentin tissue. Planktonic E. faecalis, MRSA, and P. intermedia were significantly eliminated after irradiation with 432, 36, and 1.35 J/cm2 aBL, respectively (p < 0.05). Infrared thermal imaging and cell viability tests showed that continuous aBL exposure is biocompatible in vitro. CLSM and SEM analyses revealed that the micro-LED device had a greater antimicrobial effect than CH on E. faecalis biofilm in the root canal. Conclusions: The wireless blue micro-LED device is a promising and user-friendly approach for root canal disinfection that will facilitate infection control in the root canal using aBL.

Photobiomodulation therapy for management of inferior alveolar nerve injury post-extraction of impacted lower third molars.

PURPOSE: Inferior alveolar nerve (IAN) injury is one of the most serious complications after extraction of impacted lower third molars. Photobiomodulation (PBM) therapy has been noted to reduce pain and inflammation while promoting tissue healing. This study examined the efficacy of PBM therapy tested in a case series of patients with postoperative IAN injury. MATERIAL AND METHODS: 20 patients with post-extraction IAN injury were involved in this study and divided into two groups. In the study group, PBM therapy (808-nm laser, 16 mW, 3 J/cm2) was used every other day for 2 weeks solely on post-extraction sockets in 10 patients diagnosed with IAN injury. In the control group, mecobalamine was prescribed to 10 patients with IAN injury. Objective and subjective recovery of IAN paresthesia was evaluated using clinical neurosensory testing and visual analog score. RESULTS: All patients showed improvement in both objective and subjective examination. Notably, the visual analog score was significantly improved after PBM treatment compared to the mecobalamine treatment (p < 0.05). CONCLUSION: PBM therapy with 808-nm laser appears to be an effective approach to manage paresthesia post-IAN injury following impacted third molar surgery. Given the limited sample size in this study, large-scale, placebo-controlled, multi-center randomized controlled trials are needed for further validation of this innovative treatment.

Potassium iodide enhances the photobactericidal effect of methylene blue on Enterococcus faecalis as planktonic cells and as biofilm infection in teeth.

OBJECTIVE: To explore the effectiveness, biosafety, photobleaching and mechanism of antimicrobial photodynamic therapy (aPDT) using methylene blue (MB) plus potassium iodide (KI), for root canal infections. METHODS: Different combinations and concentrations of MB, KI and 660 nm LED light were used against E. faecalis in planktonic and in biofilm states by colony-forming unit (CFU), confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM). Human gingival fibroblasts (HGF) were used for safety testing by Cell Counting Kit-8 (CCK8) and fluorescence microscopy (FLM). The photobleaching effect and mechanisms were analyzed. RESULTS: KI could not only enhance MB aPDT on E. faecalis in both planktonic and biofilm states even in a hypoxic environment, but also produced a long-lasting bactericidal effect after end of the illumination. KI could accelerate photobleaching to reduce tooth staining by MB, and the mixture was harmless for HGFs. Mechanistic studies showed the generation of hydrogen peroxide and free iodine, and iodine radicals may be formed in hypoxia. CONCLUSION: aPDT with MB plus KI could be used for root canal disinfection and clinical studies are worth pursuing.

Treatment for a complicated crown-root fracture with intentional replantation: a case report with a 3.5-year follow up.

Crown-root fractures are always challenging for pediatric dentists because of their complicated treatments and uncertain prognosis. The purpose of this case report was to describe a severe crown-root fracture successfully treated by multidisciplinary approaches including intentional replantation. After a 3.5-year follow up, the patient felt comfortable and satisfied with her tooth, and the prosthesis was functionally and esthetically acceptable. It is recommended that multidisciplinary treatment with intentional replantation is effective and necessary for similar cases to be conservatively managed.

Human Monoclonal Fab Antibodies Against West Nile Virus and its Neutralizing Activity Analyzed in Vitro and in Vivo.

The disease progression with West Nile virus (WNV) infection in humans leads to meningitis or encephalitis and may cause death, particularly among elderly and immunocompromised individuals. Passive immunity using immunoglobulins has shown efficacy in treating some patients with WNV infection, which makes the development of human anti-WNV antibodies significant. The goal of this study was to construct a Fab-specific phage display library against WNV, and to identify and select clones with neutralizing activities. Total RNA was extracted from peripheral blood lymphocytes (PBLs) of two immunized individuals, and RT-PCR was used to amplify the Fab fragments containing the heavy (V(H)) and light (V(L)) chains. The amplified genes were sequentially cloned into the recombinant antibody expression vector pComb3-H, and the Fab-specific phage display library was packaged with helper phage VCS-M13. Five rounds of panning were carried out with WNV E protein domain III, and then binding antibodies were selected by ELISA. Antigen binding specificity, complementarity determining region (CDR) sequence of V(H) and V(L), and neutralizing activity against WNV were analyzed in vitro and in vivo. Eight Fab monoclonal antibodies recognized E protein domain III from a library of 7×10(7) clones/ml. Of the eight, one (Fab 1), exhibited significant neutralizing activity, and completely blocked 100 pfu WNV infection in Vero cells at a concentration 160 µg/ml. In contrast, Fab 13 and Fab 25, showed weaker neutralizing activities, and modestly blocked 100 pfu WNV infections at concentrations of 320 µg/ml and 160 µg/ml, respectively. However, animal studies showed that Fab 1 failed to protect mice from death at the concentration of 160µg/ml indicating that the neutralizing potential of an antibody in vivo is determined by the strength of binding and the abundance of its epitope for the virion.

Identification of a novel missense mutation of MSX1 gene in Chinese family with autosomal-dominant oligodontia.

OBJECTIVES: Oligodontia is defined as the congenital absence of 6 or more permanent teeth excluding the third molar. The occurrence of non-syndromic still remains poorly understood, but in recent years some cases have been reported where mutations or polymorphisms of PAX9 and MSX1 had been associated with non-syndromic oligodontia. The objective of the present work was to study the phenotype and genotype of three generations of a Han Chinese family affected by non-syndromic autosomal-dominant oligodontia. DESIGN: We examined all individuals of the oligodontia family by clinical and radiographic examinations. Based on clinical manifestations, candidate genes MSX1 and PAX9 were picked up to analyse and screen mutations. RESULTS: Dental evaluation showed that the most commonly missing teeth are the mandibular second premolars, followed by the maxillary second premolars and maxillary lateral incisors, and subsequently the maxillary first premolars. The probability of missing a particular type of tooth is not always bilaterally symmetrical, and differences exist between maxilla and mandible. PCR-SSCP analysis and DNA sequencing revealed a novel missense mutation c.662C>A in a highly conserved homeobox sequence of MSX1 and a known polymorphisms c.347C>G. CONCLUSION: Our finding suggests the missense transversion (c.662C>A) and the polymorphisms (c.347C>G) may be responsible for oligodontia phenotype in this Chinese family.

Hyperalgesia in response to traumatic occlusion and GFAP expression in rat parabrachial [correction of parabranchial] nucleus: modulation with fluorocitrate.

We have examined, by immunocytochemical methods and nociceptive behavior assessment in rats, whether astrocytes in the parabrachial nucleus (PBN) are involved in the regulation of traumatic occlusion. The expression of glial fibrillary acidic protein (GFAP) in PBN of ipsilateral and contralateral sides was up-regulated 4 h after occlusal changes in molars, reached peak levels at 24 h, and was then gradually down-regulated. PBN astrocytes activated by traumatic occlusion were found to have enlarged cell bodies and thickened processes within 8 h. An inhibitor of glia metabolism (FCA, fluorocitrate) reduced astrocyte activation and significantly attenuated the development of pain hypersensitivity in this model. The results suggested that the GFAP-immunoreactive astrocytes in PBN within the bridge of Varolius were activated by traumatic occlusion, and that they were involved in the transmission and modulation of nociceptive information in the central nervous system. However, although astrocytes in PBN are thus probably involved in causing post-occlusal hyperalgesia, we have not been able to exclude that astrocytes at other locations also contribute to this effect.

Immune responses and protective efficacy induced by 85B antigen and early secreted antigenic target-6 kDa antigen fusion protein secreted by recombinant bacille Calmette-Guérin.

In an attempt to improve immune responses and protective efficacy, we constructed two recombinant bacille Calmette-Guérin (rBCG) strains expressing an 85B antigen (Ag85B) and early secreted antigenic target-6 kDa antigen (ESAT6) of Mycobacterium tuberculosis (MTB) fusion protein. Both rBCG strains have the same protein insertion but in a different order (Ag85B-ESAT6 and ESAT6-Ag85B). The cultured supernatant of rBCG strains and the sera from the mice immunized with the fusion protein Ag85B-ESAT6 or ESAT6-Ag85B formed a band with a fraction size of 37 kDa, equalivalent to the sum of Ag85B and ESAT6. Six weeks after BALB/c mice were immunized with BCG or rBCG, spleen lymphocytes showed significant proliferation in response to culture filtrate protein of MTB. Compared with the BCG group, mice vaccinated with rBCG elicited a high level increase of immunoglobulin G antibodies to culture filtrate protein in the serum. The gamma-interferon levels in the lymphocyte culture medium supernatants increased remarkably in the rBCG1 group, significantly higher than that of the BCG immunized group (p<0.05). Four weeks after vaccination, mice were infected with M. tuberculosis H37Rv and a dramatic reduction in the numbers of MTB colony forming units in the spleens and lungs was observed in the two rBCG immunization groups. Although these rBCG strains were more immunogenic, their protective effect was comparable to the classical BCG strain, and there were no significant differences between two rBCG groups (p>0.05).

[Changes of dentin, dental pulp and periodontium tissue in tail-suspended rats].

OBJECTIVE: To investigate the metabolic changes of calcium and phosphorus in dentin, dental pulp and periodontium in tail-suspended rats, and the functions of TGF-beta 1, c-fos, collagen-I and collagen IV in dentin, dental pulp and periodontium. METHOD: Relative percentage contents of Ca, P in dentin, dental pulp and periodontium were measured with scanning electron microscope and energy spectrum analytical system in 3 groups of rats. The expression of TGF-beta 1, c-fos, collagen-I and collagen IV were also observed. RESULT: In the suspension group, the relative percentage content of Ca declined significantly, while P increased slightly. There were no significant differences of Ca, P in alveolar bone. The expressions of TGF-beta 1, c-fos and collagen-I declined, but the expression of collagen-IV in pulp vessel increased. There were no significant changes of expressions of TGF-beta 1, c-fos, collagen-I and collagen-IV in the vicinity of PDL. After adopting artificial countermeasures, the above expressions restored partly. CONCLUSION: Weightlessness might cause abnormal mineralization in dentin, and 1.5 G artificial countermeasures could eliminate the above changes of mineral metabolism. The poor mineralization of dentin might be associated with the reduced secretion of TGF-beta 1, c-fos and collagen-I in tail-suspended rats.