Residual Bacteriome after Chemomechanical Preparation of Root Canals in Primary and Secondary Infections.

INTRODUCTION: Secondary infections may be linked to the presence of residual microorganisms within dental root canals. The purpose of this study was to investigate the bacterial composition of primary and secondary root canal infections before and after chemomechanical treatment. METHODS: Samples were collected before chemomechanical preparation (S1) and before obturation (S2) from 19 subjects (10 primary and 9 secondary infections). DNA was extracted, and the V3/V4 region of the 16S ribosomal RNA gene was amplified using the 347 F/803R primers and paired-end sequenced using the MiSeq (Illumina, San Diego, CA) instrument. RESULTS: Sequencing analysis yielded partial 16S ribosomal RNA gene sequences that were taxonomically classified into 10 phyla and 143 genera. The most prevalent phyla in the S1 and S2 samples were Firmicutes and Bacteroides; however, when comparing between sample groups, Proteobacteria seem to have been enriched in secondary infections. The dominant genera in the primary S1 samples were Bacillus, Streptococcus, and Prevotella, whereas Bacillus, Streptococcus, and Selenomonas dominated the secondary infection S1 samples. Bacillus and Marinilactibacillus were the most dominant genera in the primary and secondary S2 samples. The mean number of operational taxonomic units per sample was 32,656 (±12,124 SD) and 37,113 (±16,994 SD) in the S1 and S2 samples, respectively. Alpha and beta diversities presented the same pattern within samples from both groups. CONCLUSIONS: Great interindividual variations in the bacterial composition of the root canal biofilms were observed. There was no difference in the bacterial composition before and after treatment, although some genera survived and seem to be part of a residual microbiome. Our findings revealed a high diversity of the bacterial communities present in root canal infections after chemomechanical treatment, although the majority of the taxa detected were in low abundance.

Vitamin D3/vitamin K2/magnesium-loaded polylactic acid/tricalcium phosphate/polycaprolactone composite nanofibers demonstrated osteoinductive effect by increasing Runx2 via Wnt/ß-catenin pathway.

Vitamin D3, vitamin K2, and Mg (10%, 1.25%, and 5%, w/w, respectively)-loaded PLA (12%, w/v) (TCP (5%, w/v))/PCL (12%, w/v) 1:1 (v/v) composite nanofibers (DKMF) were produced by electrospinning method (ES) and their osteoinductive effects were investigated in cell culture test. Neither pure nanofibers nor DKMF caused a significant cytotoxic effect in fibroblasts. The induction of the stem cell differentiation into osteogenic cells was observed in the cell culture with both DKMF and pure nanofibers, separately. Vitamin D3, vitamin K2, and magnesium demonstrated to support the osteogenic differentiation of mesenchymal stem cells by expressing Runx2, BMP2, and osteopontin and suppressing PPAR-γ and Sox9. Therefore, the Wnt/ß-catenin signaling pathway was activated by DKMF. DKMF promoted large axonal sprouting and needle-like elongation of osteoblast cells and enhanced cellular functions such as migration, infiltration, proliferation, and differentiation after seven days of incubation using confocal laser scanning microscopy. The results showed that DKMF demonstrated sustained drug release for 144 h, tougher and stronger structure, higher tensile strength, increased water up-take capacity, decreased degradation ratio, and slightly lower Tm and Tg values compared to pure nanofibers. Consequently, DKMF is a promising treatment approach in bone tissue engineering due to its osteoinductive effects.

Perspective: Covid-19; emerging strategies and material technologies.

It will be remembered in history as the event that brought the world together with science and technology; the COVID-19 pandemic has allowed for decades worth of progression in both healthcare policies and technology development. It has been a show of unprecedented global health policies ranging from the legal requirement for public facemask use to the use of tough movement restrictions that has bought the world's economy to its knees. Here, we observe the impact of national lockdowns, facemask usage, and their effect on infection rates. It is clear that healthcare policies alone cannot tackle a pandemic. There is a huge pressure to develop personal protective equipment that not only has the capacity to prevent transmission but also has the ergonomics to be worn for long durations. In this work, we reveal our views and thoughts on the healthcare policies and developing materials and technology strategies that have contributed to reduce the damage of the pandemic, coming from the perspectives of materials scientists and a UK National Health Service consultant doctor.

Accelerated diabetic wound healing by topical application of combination oral antidiabetic agents-loaded nanofibrous scaffolds: An in vitro and in vivo evaluation study.

The combination of oral antidiabetic drugs, pioglitazone, metformin, and glibenclamide, which also exhibit the strongest anti-inflammatory action among oral antidiabetic drugs, were loaded into chitosan/gelatin/polycaprolactone (PCL) by electrospinning and polyvinyl pyrrolidone (PVP)/PCL composite nanofibrous scaffolds by pressurized gyration to compare the diabetic wound healing effect. The combination therapies significantly accelerated diabetic wound healing in type-1 diabetic rats and organized densely packed collagen fibers in the dermis, it also showed better regeneration of the dermis and epidermis than single drug-loaded scaffolds with less inflammatory cell infiltration and edema. The formation of the hair follicles started in 14 days only in the combination therapy and lower proinflammatory cytokine levels were observed compared to single drug-loaded treatment groups. The combination therapy increased the wettability and hydrophilicity of scaffolds, demonstrated sustained drug release over 14 days, has high tensile strength and suitable cytocompatibility on L929 (mouse fibroblast) cell and created a suitable area for the proliferation of fibroblast cells. Consequently, the application of metformin and pioglitazone-loaded chitosan/gelatin/PCL nanofibrous scaffolds to a diabetic wound area offer high bioavailability, fewer systemic side effects, and reduced frequency of dosage and amount of drug.

A novel reusable anti-COVID-19 transparent face respirator with optimized airflow.

This novel face mask is designed to be a reusable respirator with a small and highly efficient disposable fabric filter. Respirator material requirements are reduced by 75% compared to traditional designs and allow repeated cleaning or sterilization. The probability of virus particle inhalation is reduced using novel air filtration pathways, through square-waveform design to increase filter airflow. Air enters the mask from right and left side filters, while the area in front of the mouth is isolated. Clear epoxy is used for a transparent frame, allowing lip-reading, and mask edges contain a silicone seal preventing bypass of the filters. The mask is manufactured using silicone molds, eliminating electricity requirements making it economical and viable in developing countries. Computational fluid dynamics numerical studies and Fluent ANSYS software were used to simulate airflow through the filter to optimize filter air path geometry and validate mask design with realistic human requirements. The breathing cycle was represented as a transient function, and N95 filter specifications were selected as a porous medium. The novel design achieved 1.2 × 10-3 kg s-1, 20% higher than human requirements, with air streamlines velocity indicating local high speed, forcing and trapping virus particles against filter walls through centrifugal forces.

A novel treatment strategy for preterm birth: Intra-vaginal progesterone-loaded fibrous patches.

Progesterone-loaded poly(lactic) acid fibrous polymeric patches were produced using electrospinning and pressurized gyration for intra-vaginal application to prevent preterm birth. The patches were intravaginally inserted into rats in the final week of their pregnancy, equivalent to the third trimester of human pregnancy. Maintenance tocolysis with progesterone-loaded patches was elucidated by recording the contractile response of uterine smooth muscle to noradrenaline in pregnant rats. Both progesterone-loaded patches indicated similar results from release and thermal studies, however, patches obtained by electrospinning had smaller average diameters and more uniform dispersion compared to pressurized gyration. Patches obtained by pressurized gyration had better results in production yield and tensile strength than electrospinning; thereby pressurized gyration is better suited for scaled-up production. The patches did not affect cell attachment, viability, and proliferation on Vero cells negatively. Consequently, progesterone-loaded patches are a novel and successful treatment strategy for preventing preterm birth.

Evaluation of burst release and sustained release of pioglitazone-loaded fibrous mats on diabetic wound healing: an in vitro and in vivo comparison study.

In order to provide more effective treatment strategies for the rapid healing of diabetic wounds, novel therapeutic approaches need to be developed. The therapeutic potential of peroxisome proliferator-activated receptor-γ (PPAR-γ) agonist pioglitazone hydrochloride (PHR) in two different release kinetic scenarios, burst release and sustained release, was investigated and compared with in vitro and in vivo tests as potential wound healing dressings. PHR-loaded fibrous mats were successfully fabricated using polyvinyl-pyrrolidone and polycaprolactone by scalable pressurized gyration. The results indicated that PHR-loaded fibrous mats expedited diabetic wound healing in type-1 diabetic rats and did not show any cytotoxic effect on NIH/3T3 (mouse embryo fibroblast) cells, albeit with different release kinetics and efficacies. The wound healing effects of fibrous mats are presented with histological and biochemical evaluations. PHR-loaded fibrous mats improved neutrophil infiltration, oedema, and inflammation and increased epidermal regeneration and fibroblast proliferation, but the formation of hair follicles and completely improved oedema were observed only in the sustained release form. Thus, topical administration of PPAR-γ agonist in sustained release form has high potential for the treatment of diabetic wounds in inflammatory and proliferative phases of healing with high bioavailability and fewer systemic side effects.