In Vitro Effects of Silver Nanoparticles on Pathogenic Bacteria and on Metabolic Activity and Viability of Human Mesenchymal Stem Cells.

The rapid development of nanotechnology has led to the use of silver nanoparticles (Ag-NPs) in various biomedical fields. However, the effect of Ag-NPs on human mesenchymal stem cells (hMSCs) is not fully understood. Moreover, too frequent an exposure to products containing nanosilver in sublethal amounts raises widespread concerns that it will lead to the development of silver-resistant microorganisms. Therefore, this study aimed to evaluate the mechanism of action of Ag-NPs on hMSCs by analyzing the cellular uptake of Ag-NPs by the cells and its effect on their viability and to assess antimicrobial activity of Ag-NPs against emerging bacterial strains, including multidrug-resistant pathogens. For metabolic activity and viability evaluation, hMSCs were incubated with different concentrations of Ag-NPs (14 µg/mL, 7 µg/mL, and 3.5 µg/mL) for 10 min., 1 h and 24 h and subsequently analyzed for their viability by live-dead staining and metabolic activity by the MTS assay. The effect of Ag-NPs on bacterial pathogens was studied by determining their minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). In conclusion, it was observed that exposure of hMSCs to Ag-NPs of size <10 nm has no cytotoxic effect on the metabolic activity of the cells at the concentration of 3.5 µg/mL, with minimal cytotoxic effect being observed at the concentration of 14 µg/mL after 24 h of incubation. Our findings also confirmed that Ag-NPs at the concentration of 4 µg/mL are effective broad-spectrum bactericidal agents, regardless of the antibiotic-resistance mechanism present in bacteria.

Are Teachers Working with Visually Impaired Children Prepared to Be Advocates of Oral Health? Pilot Study.

BACKGROUND: Children and adolescents with visual impairment are at increased risk of oral cavity diseases. Pro-health education in their prevention and the role of educators and school counselors are extremely important in this aspect. The aim of the study was to collect information, and compare and analyze the level of pro-health awareness in the field of oral health prevention among teachers working with visually impaired children in Poland and Slovakia. METHODS: The questionnaire survey covered 109 school educators working with visually impaired children. The survey contained general information about participants concerning their knowledge of oral health, basic information about oral hygiene, and children's care needs in this area. The obtained results were statistically analyzed. RESULTS: The level of knowledge about oral health was assessed by the majority of respondents as rather good (60.56%), 28.44% as very good, and 11.01% as middling. Teaching children about oral hygiene at school was declared by a majority of them and over half of the correct answers were given by only 48.42% of the respondents. CONCLUSIONS: It is advisable to intensify the oral cavity diseases prevention training of teachers working with visually impaired children and youth and there is a great need to organize and carry out educational campaigns in schools for them.

Physicochemical Properties and Surface Characteristics of Ground Human Teeth.

Enamel, dentin and cementum apatite has a complex composition. The lack of complete reports on the chemical composition of all tooth tissues together and the need to create a modern biomaterial that reproduces the correct ratio of individual tooth mineral components prompted the authors to undertake the research. A detailed evaluation of the micro- and macro-elements of tooth powder, using various methods of chemical analysis was conducted. All four groups of human sound teeth were crushed using the grinder. A fine powder was implemented for the FTIR (Fourier Transform Infrared Spectroscopy), ICP (Inductively Coupled Plasma Optical Emission Spectometry) and for the potentiometric titration, SEM and mercury porosimetry analyses. The obtained studies indicate that there is no significant correlation in chemical composition between the different teeth types. This proves that every removed, crushed tooth free of microorganisms can be a suitable material for alveolar augmentation. It is essential to know the chemical profiles of different elements in teeth to develop a new class of biomaterials for clinical applications.

Oral Hygiene Considerations in Adult Patients with Leukemia during a Cycle of Chemotherapy.

The oral cavity is the place where the first symptoms of systemic diseases may appear. Leukemia is the malignancy of the hematopoietic system in which abnormal leukocytes are produced in the bone marrow and these cells spread to the peripheral blood. It is classified clinically on the basis of the duration and nature of the disease (acute or chronic), the type of cell involved (myeloid, lymphoid, or monocytes), and a rise in the number of abnormal cells in the blood. The study aimed to assess and compare the oral hygiene and periodontium status based on the indices in leukemic patients before and after one cycle of chemotherapy and whether the therapy had an impact on the change of these parameters. Dental indices used in clinical diagnostics were calculated: API (approximal plaque index), SBI (sulcus bleeding index), and CPI (community periodontal index). The research project was conducted at the Clinic of Hematooncology and Bone Marrow Transplantation of the Independent Public Clinical Hospital No. 1 in Lublin. The target population consisted of 102 adults with leukemia who were over 18 years of age. The time since diagnosis of the disease ranged from 1 to 10 years. The data were evaluated in the Statistica 12 software with the respective tests. In the majority of patients, both before and after chemotherapy, improper oral hygiene and severe generalized periodontitis were confirmed. The cycle of chemotherapy that was used did not correlate with the change of patients' oral hygiene and periodontium state. Unsatisfactory oral hygiene and periodontal health has to be addressed with urgent dental treatment to avoid systemic complications in leukemic patients.

Selected Applications of Chitosan Composites.

Chitosan is one of the emerging materials for various applications. The most intensive studies have focused on its use as a biomaterial and for biomedical, cosmetic, and packaging systems. The research on biodegradable food packaging systems over conventional non-biodegradable packaging systems has gained much importance in the last decade. The deacetylation of chitin, a polysaccharide mainly obtained from crustaceans and shrimp shells, yields chitosan. The deacetylation process of chitin leads to the generation of primary amino groups. The functional activity of chitosan is generally owed to this amino group, which imparts inherent antioxidant and antimicrobial activity to the chitosan. Further, since chitosan is a naturally derived polymer, it is biodegradable and safe for human consumption. Food-focused researchers are exploiting the properties of chitosan to develop biodegradable food packaging systems. However, the properties of packaging systems using chitosan can be improved by adding different additives or blending chitosan with other polymers. In this review, we report on the different properties of chitosan that make it suitable for food packaging applications, various methods to develop chitosan-based packaging films, and finally, the applications of chitosan in developing multifunctional food packaging materials. Here we present a short overview of the chitosan-based nanocomposites, beginning with principal properties, selected preparation techniques, and finally, selected current research.

Changes of Dentition State in Leukemic Patients during Chemotherapy.

A number of systemic diseases including hematological disorders have manifestations in the oral cavity region. These manifestations may often represent early signs of the underlying hematopoietic disease and occur frequently in leukemia. Despite the fact that leukemia has long been known to be associated with oral health deterioration, the available literature on this topic consists mostly of case reports, without data to conclude these. The aim of the study was to assess dentition state in leukemic patients during one cycle of chemotherapy and its correlation with blood parameters. The study included 102 adults treated because of leukemia at the Clinic of Haemato-Oncology and Bone Marrow Transplantation at the university hospital in Lublin, Poland. The sample group consisted of 51 women and 51 men aged 22 to 72 (54.07 ± 10.33) with following diagnoses: Acute myelogenous leukemia (AML)-55 patients (53.92%), Chronic lymphocytic leukemia (CLL)-17 patients (16.67%), Acute lymphoblastic leukemia (ALL)-16 patients (15.69%), Chronic myelogenous leukemia (CML)-10 patients (9.80%), Acute promyelocytic leukemia (APL) -3 patients (2.94%), Chronic hairy cell leukemia (HCL)-1 patient (0.98%). DMFT index was used to assess dentition state. After the cycle of chemotherapy, their dentition state changed in terms of decayed, missing and filled teeth and correlated with hematological parameters. Adult patients with leukemia have high dental treatment needs, and high number of missing teeth; thus, a comprehensive and fast dental treatment is necessary to avoid systemic complications and ensure better quality of life.