Comparison of the effects of fluoride varnish containing silver nanoparticles and conventional fluoride varnish on the surface microhardness of tooth enamel.

BACKGROUND: Nano-silver fluoride (NSF) has been introduced to improve enamel lesions. The effective use of varnishes is important in the prevention of dental caries. OBJECTIVES: The study aimed to compare the effect of conventional sodium fluoride varnish with the same varnish containing 1% and 2% silver nanoparticles (AgNP) on the surface microhardness of enamel. MATERIAL AND METHODS: The baseline surface microhardness of 40 premolar teeth was measured using a Vickers microhardness tester. After immersing the samples in a demineralizing agent for 24 h, the microhardness was measured again. In group B, a layer of conventional fluoride varnish was applied to the tooth surfaces using a microbrush with soft bristles, following the manufacturer's instructions. Groups C and D were treated with 1% and 2% NSF varnishes, respectively, while group A received no varnish. Surface microhardness tests were conducted on all specimens, including those previously tested. RESULTS: The microhardness of the enamel surface increased significantly in all 3 test groups compared to the microhardness after demineralization (p < 0.05). CONCLUSIONS: Conventional fluoride varnish and fluoride varnishes containing 1% and 2% AgNP are equally effective in remineralizing initial caries.

Oral administration of silver nanoparticles-adorned starch as a growth promotor in poultry: Immunological and histopathological study.

Silver nanoparticles (AgNPs) have recently emerged as promising growth promoters and immune-lifting agents in the poultry industry. This study investigated the potential impact of AgNP supplementation in the drinking water (DW) of broiler chickens during the fattening period. AgNPs were produced through chemical reduction using starch as a reducing and stabilizing agent. Different concentrations (1-5 ppm) of AgNPs were prepared and added to the DW of five different groups of chickens. Results confirmed efficient and safe application of AgNPs in DW at concentrations up to 2 ppm in term of growth performance (body weight, body weight gain, and feed conversion ratio) and hematological parameters. However, higher concentrations (3-5 ppm) induced dose-dependent mild-to-moderate adverse effects on hematological, biochemical, and oxidative parameters (MDA, TAC, and GSH-px). While growth performance, gene expression of fibroblast growth factor 2 (FGF2), vascular endothelial growth factor A (VEGFA),and insulin-like growth factor (IGF1) in muscle, histopathological and immunohistochemical evaluation of liver, kidney, spleen, bursa, and thymus, and ultrastructural analysis of breast muscle were not significantly affected, even at high concentrations of AgNPs. Therefore, supplementation of AgNPs up to 2 ppm in the DW of broilers is promising.

The effect of the combined use of silver diamine fluoride and potassium iodide in disrupting the plaque biofilm microbiome and alleviating tooth discoloration: A systematic review.

Silver diamine fluoride (SDF) is used in minimally invasive dentistry for arresting dental caries. However, discoloration of teeth is a significant side effect that has limited the use of SDF. Hence, the application of potassium iodide (KI) following SDF has been proposed to ameliorate the staining. Although antimicrobial activity is one of the major mechanisms of the caries-arresting effect of SDF, the antimicrobial potency of SDF/KI combination is unclear. Thus, the primary objective of this systematic review was to appraise the studies on the antimicrobial efficacy of SDF/KI combination on cariogenic microbes. The secondary objective was to summarize the evidence on the potential of KI in reducing the discoloration associated with the application of SDF. Electronic databases of Medline via PubMed, Cochrane Library, Web of Science, and EBSCO host were searched for English language manuscripts from January 2005 to 15th November 2020. The reference lists of these manuscripts were manually searched for additional studies. Twelve studies were included in the final analysis, seven of which have investigated the antimicrobial efficacy of SDF/KI, and the rest have examined the anti-staining potential of KI. The exploratory findings from the reviewed articles revealed the promising antimicrobial potential of SDF/KI on cariogenic microbes associated with dentine caries. There is, however, contradictory evidence on the effect of SDF/KI on tooth color. The reviewed in-vitro studies indicated significant effectiveness of KI in preventing staining. A clinical trial on primary dentition showed 25% reduction in the incidence of staining by SDF after applying KI, while a clinical study on root caries in adults showed no significant effect. Within the methodological limitations of this review, we conclude that for arresting dental caries, SDF could be combined with KI, as there may be a lower likelihood of staining. Further, well-designed clinical trials on the antimicrobial and anti-staining effect of SDF/KI are needed to obtain more robust evidence.

A systematic review of preclinical data regarding commercial silver-coated vascular grafts.

OBJECTIVE: Vascular graft infection (VGI) is a serious complication with high mortality and morbidity rates. Several measures could be taken to decrease this risk, including the use of silver-containing vascular grafts. However, to date, no clinical advantages have been reported. This study reviews the outcome of preclinical studies focusing on the role of commercially available silver-coated grafts in the prevention of VGI. METHODS: A systematic review was performed with a focus on the preclinical role of commercially available silver-coated vascular grafts in the prevention and treatment of VGI. A comprehensive search was conducted in Medline, Embase, and Web of Science. RESULTS: Nine in vitro and five in vivo studies were included. Two commercial grafts were used (INTERGARD SILVER and Silver Graft). In vitro studies used both gram-positive and gram-negative strains. A positive antimicrobial effect was observed in seven of nine studies (77.8%). A delayed antifungal effect against Candida species was observed in vitro, but disappeared when adding serum proteins. In vivo studies witnessed a microbicidal effect in two out of five studies (40%), but only tested a single causative pathogen (ie, Staphylococcus aureus). CONCLUSIONS: Both in vitro and in vivo studies demonstrated conflicting and mixed results concerning the antimicrobial efficacy of commercially available silver-containing grafts in the prevention of VGI. In general, the study setup was heterogeneous in the different articles. Given the lack of convincing preclinical evidence and their poor performance in clinical studies, more data are needed at this time to guide the appropriate use of silver grafts.

Systemic effects and impact on the gut microbiota upon subacute oral exposure to silver acetate in rats.

CONTEXT: The addition of silver (Ag) to food items, and its migration from food packaging and appliances results in a dietary exposure in humans, estimated to 70-90 µg Ag/day. In view of the well-known bactericidal activity of Ag ions, concerns arise about a possible impact of dietary Ag on the gut microbiota (GM), which is a master determinant of human health and diseases. Repeated oral administration of Ag acetate (AgAc) can also cause systemic toxicity in rats with reported NOAELs of 4 mg AgAc/b.w./d for impaired fertility and 0.4 mg AgAc/b.w./d for developmental toxicity. OBJECTIVE: The objective of this study was to investigate whether oral exposure to AgAc can induce GM alterations at doses causing reproductive toxicity in rats. METHODS: Male and female Wistar rats were exposed during 10 weeks to AgAc incorporated into food (0, 0.4, 4 or 40 mg/kg b.w./d), and we analyzed the composition of the GM (α- and ß-diversity). We documented bacterial function by measuring short-chain fatty acid (SCFA) production in cecal content. Ferroxidase activity, a biomarker of systemic Ag toxicity, was measured in serum. RESULTS AND CONCLUSIONS: From 4 mg/kg b.w./d onwards, we recorded systemic toxicity, as indicated by the reduction of serum ferroxidase activity, as well as serum Cu and Se concentrations. This systemic toxic response to AgAc might contribute to explain reprotoxic manifestations. We observed a dose-dependent modification of the GM composition in male rats exposed to AgAc. No impact of AgAc exposure on the production of bacterial SCFA was recorded. The limited GM changes recorded in this study do not appear related to a reprotoxicity outcome.

The toxic influence of silver and titanium dioxide nanoparticles on cultured ovarian granulosa cells.

The application of metal nanoparticles in modern society is growing, but there is insufficient data concerning their influence on reproductive processes and comparison of their biological activity. The present experiments aimed to compare the effects of silver and titanium dioxide nanoparticles (AgNPs and TiO2NPs) on ovarian granulosa cell functions. AgNPs and TiO2NPs were added to culture of porcine granulosa cells at doses 0, 0.01, 0.1, 1 or 10 µg/mL. The mRNAs for proliferating cell nuclear antigen (PCNA), cyclin B1, bax and caspase 3 were quantified by RT-PCR; release of progesterone was analyzed by ELISA. It was shown that both AgNPs and TiO2NPs significantly reduced all the measured parameters. ED50 of the inhibitory influence of AgNPs on the main ovarian cell parameters was higher than ED50 of TiO2NPs. The ability of AgNPs and TiO2NPs to suppress ovarian granulosa cell functions should be taken into account by their application.

Silver diamine fluoride compared to atraumatic restorative technique for the treatment of caries in primary and mixed first phase dentition. / Fluoruro diamino de plata comparado con técnica de restauración atraumática para el tratamiento de caries cavitadas en dentición primaria y mixta primera fase.

INTRODUCTION: Cavitated carious lesions in primary and mixed dentition require prompt treatment to control caries progression. Silver diamine fluoride has emerged as an alternative to the atraumatic restorative technique due to its easy application. However, there is still uncertainty regarding its effectiveness and safety. METHODS: We searched in Epistemonikos, the largest database of systematic reviews in health, which is maintained by screening multiple information sources, including MEDLINE, EMBASE, Cochrane, among others. We extracted data from the systematic reviews, reanalyzed data of primary studies, conducted a metanalysis and generated a summary of findings table using the GRADE approach. RESULTS AND CONCLUSIONS: We identified ten systematic reviews, including two studies overall, which are randomized trials. We concluded that silver diamine fluoride compared to the atraumatic restorative technique may increase the arrest of caries in primary and mixed first phase dentition, however, the certainty of the evidence has been assessed as low. On the other hand, treatment with silver diamine fluoride compared to the atraumatic restorative technique (ART) probably increases the risk of adverse events.

INTRODUCCIÓN: Las lesiones de caries cavitadas en dentición primaria y mixta requieren un tratamiento oportuno, para evitar así la progresión de la caries. El fluoruro diamino de plata ha surgido como una alternativa a la técnica de restauración atraumática debido a su fácil aplicación. Sin embargo, aún existe incertidumbre en relación a su efectividad y seguridad. MÉTODOS: Realizamos una búsqueda en Epistemonikos, la mayor base de datos de revisiones sistemáticas en salud, la cual es mantenida mediante el cribado de múltiples fuentes de información, incluyendo MEDLINE, EMBASE, Cochrane, entre otras. Extrajimos los datos desde las revisiones identificadas, analizamos los datos de los estudios primarios, realizamos un metanálisis y preparamos una tabla de resumen de los resultados utilizando el método GRADE. RESULTADOS Y CONCLUSIONES: Identificamos diez revisiones sistemáticas que en conjunto incluyeron dos estudios primarios, ambos ensayos aleatorizados. Concluimos que el fluoruro diamino de plata en comparación a la técnica de restauración atraumática podría aumentar el arresto de caries en dentición primaria y mixta primera fase, pero la certeza de la evidencia ha sido evaluada como baja. Por otra parte, el tratamiento con fluoruro diamino de plata comparado con la técnica de restauración atraumática (ART) probablemente aumenta el riesgo de eventos adversos.

Injectable polypeptide-engineered hydrogel depot for amplifying the anti-tumor immune effect induced by chemo-photothermal therapy.

The immunosuppressive tumor microenvironment has caused great obstacles to tumor immunotherapy, especially where less tumor-associated antigens are released from tumor sites. Herein, a Ag2S QD/DOX/Bestatin@PC10ARGD genetically engineered polypeptide hydrogel PC10ARGD as a sustained-release material was developed for mammary carcinoma treatment. A near-infrared silver sulfide (Ag2S) QD as a photosensitizer was encapsulated into the hydrophobic cavity formed by the self-assembly of the polypeptide nanogel (PC10ARGD) for photothermal therapy. The water-soluble drug DOX and Bestatin were integrated into the PC10ARGD hydrogel. The photothermal effect could trigger the sustained release of the DOX, which could be applied to initiate in situ vaccination. Bestatin as an immune-adjuvant drug could amplify the body's immune function. The results of in vivo therapy tests exhibited that the Ag2S QD/DOX/Bestatin@PC10ARGD hydrogel with laser irradiation could activate anti-tumor immune effects that inhibit the growth of primary tumors and distal lung metastatic nodules. Meanwhile, a safer lower-temperature with multiple laser irradiation treatment strategy exhibited more effective tumor-killing performance (84.4% tumor inhibition rate) and promoted the penetration of immune cells into the tumor tissue. The CD8+ and CD4+ cytotoxic T cells ratio was increased by 5.3 and 10 times, respectively, thus exhibiting a good prognostic signal. The multifunctional polypeptide hydrogel as a green manufacturing and engineering material is promising to serve as a cancer vaccine for anticancer applications.

Tumor Microenvironment-Activated NIR-II Nanotheranostic System for Precise Diagnosis and Treatment of Peritoneal Metastasis.

Activatable theranostic systems show potential for improved tumor diagnosis and therapy owing to high detection specificities, effective ablation, and minimal side-effects. Herein, a tumor microenvironment (TME)-activated NIR-II nanotheranostic system (FEAD1) for precise diagnosis and treatment of peritoneal metastases is presented. FEAD1 was fabricated by self-assembling the peptide Fmoc-His, mercaptopropionic-functionalized Ag2 S quantum dots (MPA-Ag2 S QDs), the chemodrug doxorubicin (DOX), and NIR absorber A1094 into nanoparticles. We show that in healthy tissue, FEAD1 exists in an NIR-II fluorescence "off" state, because of Ag2 S QDs-A1094 interactions, while DOX remains in stealth mode. Upon delivery of FEAD1 to the tumor, the acidic TME triggers its disassembly through breakage of the Fmoc-His metal coordination and DOX hydrophobic interactions. Release of A1094 switches on Ag2 S fluorescence, illuminating the tumor, accompanied by burst release of DOX within the tumor tissue, thereby achieving precise tumor theranostics. This TME-activated theranostic strategy holds great promise for future clinical applications.

Biodistribution and organ oxidative damage following 28 days oral administration of nanosilver with/without coating in mice.

This study evaluated the biodistribution and organ oxidative effects of silver nanoparticles (AgNPs) coated with/without polyvinylpyrrolidone (PVP) (AgNP-20 and AgNP-PVP) in mice; these were administered by gavage at a dose of 10-250 mg/kg body weight per day for 28 days. The results showed that both the AgNPs could induce subacute toxicity and oxidative damage to mice and were mainly accumulated in the liver and spleen and excreted by feces. AgNPs could be absorbed into blood and might cross the blood-brain barrier, and be distributed extensively in mice. The malondialdehyde content in the liver, lungs and kidneys increased in both AgNP groups, while the content of glutathione decreased, and the activity of superoxide dismutase increased at first and then decreased along with the increased doses. Inflammatory pathological changes in the lung and liver at high dose of both AgNPs were consistent with increases in glutamate pyruvic transaminase, glutamate oxaloacetic transaminase and the total protein in serum detection. The Ag content was detected in organs, with the highest content in the liver, followed by spleen, while the Ag content in feces was about 500 times higher than that in urine. AgNP-PVP could induce higher oxidative stress and subacute toxicity than AgNP-20 at the same dose, which might be related to the higher concentrations and more Ag+ ions released in mice after AgNP-PVP exposure. The data from this research provided information on toxicity and biodistribution of AgNPs following gavage administration in mice, and might shed light for future application of AgNPs in daily life.

Rapid Intestinal Uptake and Targeted Delivery to the Liver Endothelium Using Orally Administered Silver Sulfide Quantum Dots.

Quantum dots (QDs) are used for imaging and transport of therapeutics. Here we demonstrate rapid absorption across the small intestine and targeted delivery of QDs with bound materials to the liver sinusoidal endothelial cells (LSECs) or hepatocytes in vitro and in vivo following oral administration. QDs were radiolabeled with 3H-oleic acid, with a fluorescent tag or 14C-metformin placed within a drug binding site. Three different biopolymer shell coatings were compared (formaldehyde-treated serum albumin (FSA), gelatin, heparin). Passage across the small intestine into mesenteric veins is mediated by clathrin endocytosis and micropinocytosis. 60% of an oral dose of QDs was rapidly distributed to the liver within 30 min, and this increased to 85% with FSA biopolymer coating. Uptake into LSECs also increased 3-fold with FSA coating, while uptake into hepatocytes was increased from 40% to 85% with gelatin biopolymer coating. Localization of QDs to LSECs was confirmed with immunofluorescence and transmission electron microscopy. 85% of QDs were cleared within 24 h of administration. The bioavailability of 14C-metformin 2 h post-ingestion was increased 5-fold by conjugation with QD-FSA, while uptake of metformin into LSECs was improved 50-fold by using these QDs. Endocytosis of QDs by SK-Hep1 cells (an LSEC immortal cell line) was via clathrin- and caveolae-mediated pathways with QDs taken up into lysosomes. In conclusion, we have shown high specificity targeting of the LSEC or hepatocytes after oral administration of QDs coated with a biopolymer layer of FSA or gelatin, which improved the bioavailability and delivery of metformin to LSECs.

Healthy Kids Cambodia - A novel approach to triage for dental care in a population with extreme caries experience.

OBJECTIVES: To describe the disease experiences and treatment provided according to a set of novel triage criteria among children in the Healthy Kids Cambodia project. METHODS: The present study describes the management of caries using the Healthy Kids Cambodia (HKC) strategy at one school in Phnom Penh, Cambodia. Treatment was provided across three levels of care based on a set of simple screening criteria. All children received Level 1 (L1) care, which included application of 30% silver diammine fluoride (SDF) to arrest dental caries. Level 2 (L2) care involved use of atraumatic restorative treatment (ART) and GIC fissure sealants for children between six and eight years of age, and for older children who had one or more cavitated lesions on permanent posterior teeth. Level 3 care involved conventional dental rehabilitation for those children with cavitated lesions in permanent anterior teeth, acute infections, pulpally involved permanent teeth or carious permanent posterior teeth that were not restorable using ART. Three activities were evaluated: (i) screening of all children at the school using the HKC triage criteria; (ii) a detailed re-examination of children in Grades 3 and 4; and (iii) a clinical audit of treatment provided at Level 3 (L3). RESULTS: 1194 children were screened using the HKC approach, and a sample of 304 8- to 12-year-old children was re-examined. Among those who were re-examined, 48 (15.7%) had been referred for L3 treatment and 88 (28.9%) referred for L2 (only). There was a significant difference in baseline caries experience by referral level, whereby those referred to higher levels of care had more severe caries experience. All children in the L3 category required advanced rehabilitative care. CONCLUSIONS: The application of a triage system by dental students was successful in identifying children in greatest need of complex care (L3). Further research may better validate the system for caries management.

Fluoruro diamino de plata comparado con técnica de restauración atraumática para el tratamiento de caries cavitadas en dentición primaria y mixta primera fase / Silver diamine fluoride compared to atraumatic restorative technique for the treatment of caries in primary and mixed first phase dentition

INTRODUCCIÓN: Las lesiones de caries cavitadas en dentición primaria y mixta requieren un tratamiento oportuno, para evitar así la progresión de la caries. El fluoruro diamino de plata ha surgido como una alternativa a la técnica de restauración atraumática debido a su fácil aplicación. Sin embargo, aún existe incertidumbre en relación a su efectividad y seguridad. MÉTODOS: Realizamos una búsqueda en Epistemonikos, la mayor base de datos de revisiones sistemáticas en salud, la cual es mantenida mediante el cribado de múltiples fuentes de información, incluyendo MEDLINE, EMBASE, Cochrane, entre otras. Extrajimos los datos desde las revisiones identificadas, analizamos los datos de los estudios primarios, realizamos un metanálisis y preparamos una tabla de resumen de los resultados utilizando el método GRADE. RESULTADOS Y CONCLUSIONES: Identificamos diez revisiones sistemáticas que en conjunto incluyeron dos estudios primarios, ambos ensayos aleatorizados. Concluimos que el fluoruro diamino de plata en comparación a la técnica de restauración atraumática podría aumentar el arresto de caries en dentición primaria y mixta primera fase, pero la certeza de la evidencia ha sido evaluada como baja. Por otra parte, el tratamiento con fluoruro diamino de plata comparado con la técnica de restauración atraumática (ART) probablemente aumenta el riesgo de eventos adversos

INTRODUCTION: Cavitated carious lesions in primary and mixed dentition require prompt treatment to control caries progression. Silver diamine fluoride has emerged as an alternative to the atraumatic restorative technique due to its easy application. However, there is still uncertainty regarding its effectiveness and safety. METHODS: We searched in Epistemonikos, the largest database of systematic reviews in health, which is maintained by screening multiple information sources, including MEDLINE, EMBASE, Cochrane, among others. We extracted data from the systematic reviews, reanalyzed data of primary studies, conducted a metanalysis and generated a summary of findings table using the GRADE approach. RESULTS AND CONCLUSIONS: We identified ten systematic reviews, including two studies overall, which are randomized trials. We concluded that silver diamine fluoride compared to the atraumatic restorative technique may increase the arrest of caries in primary and mixed first phase dentition, however, the certainty of the evidence has been assessed as low. On the other hand, treatment with silver diamine fluoride compared to the atraumatic restorative technique (ART) probably increases the risk of adverse events.

Clinical and Antimicrobial Efficacy of a Silver Foam Dressing With Silicone Adhesive in Diabetic Foot Ulcers With Mild Infection.

The use of an antimicrobial dressing instead of a non-antimicrobial dressing may increase the number of diabetic foot ulcers healed over a medium-term follow-up period. The study aim was to evaluate the clinical and microbiological efficacy of a silver foam dressing in the management of diabetic foot ulcers. We conducted a single-center, prospective, open, noncontrolled study involving 21 outpatients with diabetic foot ulcers with mild infection. All patients received standard of care for their wounds and a silver foam dressing with silicone adhesive was applied twice per week for wound management during a 6-week treatment period. Soft tissue punch biopsies were taken every second week for qualitative and quantitative microbiological analysis. Wounds were assessed at patient admission, and wound bed tissue was evaluated for presence, quality, and consistency of granulation tissue. Clinical evaluation revealed improvements in wound conditions as a result of treatment with the silver dressing. Wollina wound scores improved significantly, from a mean score of 3.9 ± 1.6 points at inclusion to 6.1 ± 1.3 points at the end of the study (n = 19, P < .001). Treatment with the silver dressing resulted in significant decreases in the bioburden of classically considered diabetic foot ulcer pathogenic organisms such as Staphylococcus aureus, including methicillin-resistant Staphylococcus aureus, Enterobacteriaceae species, Pseudomonas aeruginosa, and other nonfermenting gram-negative bacilli. Findings revealed that the use of silver foam dressing significantly reduced the pathogenic bacterial load and markedly improved the clinical outcome in patients with diabetic foot ulcer with mild infection over a 6-week treatment period.

Multifactorial Painful Leg Ulcers Due to Hyperhomocysteinemia, Plasminogen Activator Inhibitor-1 4G/5G Heterozygote Gene Mutation, and Beta Thalassemia Minor: A Case Report.

Leg ulcers may occur due to many autoimmune, hereditary, inflammatory, and infectious causes including venous, arterial, and neuropathic ulcers. Hyperhomocysteinemia is a metabolic disorder caused by various enzyme defects in methionine metabolism. The most common cause is methylenetetrahydrofolatreductase (MTHFR) enzyme gene mutations. Hyperhomocysteinemia is an independent risk factor for deep vein thrombosis and peripheral arterial disease. The effects of endothelial cell damage on smooth muscle hypertrophy, platelet aggregation, coagulation, and fibrinolysis cause atherogenesis and thrombosis, leading to venous and arterial lower extremity ulcers. In this article, we report the case of a 47-year-old male patient who was admitted to our clinic due to painful leg ulcers that started 1 year ago. He had a history of vena cava inferior thrombosis, deep vein thrombosis, and 40 pack-year smoking. Histopathological examination of punch biopsy taken from ulcerative lesion showed intense inflammatory infiltration in the middle dermis, erythrocyte extravasation, leukocytoclasia, and thrombus formation in a small diameter venule lumen. There were nonspecific findings in direct immunofluorescence examination. He was found as having MTHFR C677T homozygote and plasminogen activator inhibitor-1 4G/5G heterozygote gene mutation with high homocysteine level of 22.90 µmol/L, and he was diagnosed as hyperhomocysteinemia. He was recommended to quit smoking because it triggered thrombosis in hyperhomocysteinemia. Herein, we present a case of hyperhomocysteinemia due to MTHFR mutation, which is one of the rare hereditary thrombophilia causes.

Effective Topical Delivery of H-AgNPs for Eradication of Klebsiella pneumoniae-Induced Burn Wound Infection.

The aim of the present study was to explore the therapeutic efficacy of microemulsion-based delivery of histidine-capped silver nanoparticles in eradicating Klebsiella pneumoniae-induced burn wound infection. The developed microemulsion was characterized on the basis of differential light scattering, phase separation, refractive index, and specific conductance. Emulgel was prepared and characterized on the basis of thixotropy, texture, differential scanning calorimetry, and release kinetics. Emulgel was further evaluated in skin irritation and in vivo studies, namely full-thickness K. pneumoniae-induced burn wound infection treatment via topical route. Efficacy of treatment was evaluated in terms of bacterial load, histopathology, wound contraction, and other infection markers. The developed emulgel provided significant in vivo antibacterial activity of histidine-capped silver nanoparticle preparations via topical route and resulted in reduction in bacterial load, wound contraction, and enhanced skin healing as well as decrement of inflammatory markers such as malondialdehyde, myeloperoxidase, and reactive nitrogen intermediate compared to untreated animals. The present study encourages the further employment of histidine-capped silver nanoparticles along with microemulsion-based drug delivery system in combating antibiotic-resistant topical infections.

A new protocol and standard of care for managing open crown margins.

Open margins on indirect restorations (such as crowns) are the bane of dentists. Judging margins is a subjective undertaking, and there is no agreement among dentists on "how open is open?" Board actions and lawsuits commonly include charges concerning open margins. Immediate replacement of the offending restoration is claimed as the standard of care, particularly when litigation or state dental board actions are involved. However, repair and monitoring of margins are options that have recently become available. These approaches have been widely accepted and are less invasive alternatives to immediate replacement. Silver diamine fluoride (SDF) has provided new options for the management of margins. SDF, which is inexpensive and easy to apply, kills pathogens; hardens softened dentin (making it more acid and abrasion resistant); and does not stain sound dentin, enamel, or porcelain. SDF does stain any caries black. Except for those with demonstrably grossly open margins, restorations with marginal defects can and should be treated conservatively. Repairing or resealing, where possible, along with continued monitoring of all indirect restorations, has now become the standard of care. If caries develops, the tooth can often be conservatively treated by applying a layer of SDF. Only within the esthetic zones would the option of repair or replacement of the restoration be necessary.

Pharmacokinetics, Tissue Distribution and Excretion of Ag2S Quantum Dots in Mice and Rats: the Effects of Injection Dose, Particle Size and Surface Charge.

PURPOSE: We systematically investigated the effects of injection dose, particle size and surface charge on the pharmacokinetics, tissue distribution and excretion of Ag2S quantum dots (Qds) in rats and mice. METHODS: Three different doses of Ag2S Qds with similar size and composition were administrated to rats and mice. The effect of size and surface charge was investigated with the injection of three sizes (5, 15 and 25 nm) of Ag2S Qds possessing similar surface charge, as well as 5 nm Qds with a positive surface charge. RESULTS: Results indicated that pharmacokinetics and biodistribution of Ag2S Qds were strongly dose, particle size and surface charge dependent. By increasing the dose from 0.5 to 4.0 mg/kg, mean residence time (MRT) and apparent volume of distribution at steady state (Vss) were increased while clearance (CL) was decreased. Qds with a negative surface charge had significantly larger MRT and Vss values than positively charged particles, but their CL was about 50% lower than that of positively charged ones. By increasing Qds size from 5 to 25 nm, CL was increased while MRT and AUC were decreased. CONCLUSIONS: This study establishes comprehensive principles for the rational design and tailoring of Ag2S Qds for biomedical applications. Graphical Abstract The effects of injection dose, particle size and surface charge on pharmacokinetics and tissue distribution of Ag2S Qds after intravenous injection into rats and mice were investigated.

In vitro evaluation of drug release and antibacterial activity of a silver-loaded wound dressing coated with a multilayer system.

The goal of the study was to elaborate an antibacterial silver wound dressing covered by a protective coating that would prevent silver diffusion toward skin without losing its biocide properties. Therefore, non woven polyethyleneterephtalate (PET) textiles were pre-treated by two types of polysaccharides - chitosan and cyclodextrin - both crosslinked with citric acid by a pad/dry/cure process. Both types of resulting thermofixed textiles carrying the citrate crosslinks were then impregnated in silver solution followed by a thermal treatment and were finally coated by Layer-by-Layer (L-b-L) deposition of a polyelectrolyte multilayer (PEM) film consisting of anionic water-soluble poly-cyclodextrin and cationic chitosan. The influence of the process parameters was investigated in terms of silver adsorption capacity, PEM system build-up, silver kinetics of release and antibacterial activity. We demonstrate i) the utility of the intermediate thermal treatment step in the reduction of silver leakage in the polyelectrolyte solutions used in the L-b-L process, ii) that silver adsorption on the preliminary thermofixed layers did not affect the PEM system build-up, iii) the slowing down of silver release kinetic thanks to the PEM coating, iv) the preservation of the antibacterial activity despite the PEM coating.