Biological Effects and Toxicity of Compounds Based on Cured Epoxy Resins

The aim of this work was to investigate selected biological and toxicity properties of cured epoxy resin-based compounds based on a bisphenol A epoxy resin, cold-cured by a polyamide and containing two types of metal powders (aluminum and copper). This study involved cytotoxicity analysis, pH measurements, absorbance measurements and sterilization. The cytotoxicity analysis was conducted to determine the harmful degree of the cured epoxy resin. Aimed at identifying toxic agents in cured compounds, the cytotoxicity analysis involved absorbance measurements in an entire wavelength range. Cytotoxicity and absorbance results demonstrated that the extracts of all the tested resin samples had no cytotoxic effects on the cells of living organisms. The absorbance values obtained over the entire wavelength range did not point to the formation of aggregations, which proved that no toxic agents harmful to living organisms were extracted from the resin samples. Based on the results obtained, it can be concluded that all tested compounds, based on epoxy resins, which are also used as adhesives in various applications, are essentially safe materials when using such formulations in a cured state

European student wellness, stress, coping, support and perceptions about remote dental training during COVID-19

Objectives: The aim of this study was to compare wellness, stress, ability to cope, social support and perceptions about remote training amongst European dental students during COVID-19. Methods: 1795 undergraduate dental students from six countries and eight dental schools participated. The anonymous survey collected data about different aspects in each of the following domains: wellness, stress, ability to cope, social support and perceptions about remote training. Complex multi-item scales were used for all domains. Results: There were differences amongst countries in all the domains. Overall, student stress scores were lower than either their coping or support scores. The highest wellness score (mean ±sd) was observed in Romania: 62.5% ± 11.2% whilst the highest mean stress scores were observed in Albania: 46.3% ± 11.7% and Lithuania: 42.2% ± 13.8%. Overall, student stress and coping ability scores were lower and their support scores higher. About 10% of students did not have any support. In the linear multivariable regression analysis, significant predictors of wellness were being female (β = 0.073), not being in a graduating year (β = 0.059), having less stress (β = 0.222), ability to cope (β = 0.223) and having support (β = 0.179). The student positive perceptions about remote training were predicted by less stress (β = 0.080), coping (β = 0.182) and support (β = 0.057). Conclusions: Students varied in wellness, stress, coping, social support and perceptions of remote training. Also, there were significant differences amongst students from different countries. Coping was the best predictor of both student wellness and their positive perceptions about remote training

A Short Review of the Toxicity of Dentifrices—Zebrafish Model as a Useful Tool in Ecotoxicological Studies

This review aims to summarize the literature data regarding the effects of different toothpaste compounds in the zebrafish model. Danio rerio provides an insight into the mechanisms of the ecotoxicity of chemicals as well as an assessment of their fate in the environment to determine long-term environmental impact. The regular use of adequate toothpaste with safe active ingredients possessing anti-bacterial, anti-inflammatory, anti-oxidant, and regenerative properties is one of the most effective strategies for oral healthcare. In addition to water, a typical toothpaste consists of a variety of components, among which three are of predominant importance, i.e., abrasive substances, fluoride, and detergents. These ingredients provide healthy teeth, but their environmental impact on living organisms are often not well-known. Each of them can influence a higher level of organization: subcellular, cellular, tissue, organ, individual, and population. Therefore, it is very important that the properties of a chemical are detected before it is released into the environment to minimize damage. An important part of a chemical risk assessment is the estimation of the ecotoxicity of a compound. The zebrafish model has unique advantages in environmental ecotoxicity research and has been used to study vertebrate developmental biology. Among others, the advantages of this model include its external, visually accessible development, which allows for providing many experimental manipulations. The zebrafish has a significant genetic similarity with other vertebrates. Nevertheless, translating findings from zebrafish studies to human risk assessment requires careful consideration of these differences

Contemporary Approach to the Porosity of Dental Materials and Methods of Its Measurement

Porosity is an important parameter for characterizing the microstructure of solids that corresponds to the volume of the void space, which may contain fluid or air, over the total volume of the material. Many materials of natural and technically manufactured origin have a large number of voids in their internal structure, relatively small in size, compared to the characteristic dimensions of the body itself. Thus, porosity is an important feature of industrial materials, but also of biological ones. The porous structure affects a number of material properties, such as sorption capacity, as well as mechanical, thermal, and electrical properties. Porosity of materials is an important factor in research on biomaterials. The most popular materials used to rebuild damaged tooth tissues are composites and ceramics, whilst titanium alloys are used in the production of implants that replace the tooth root. Research indicates that the most comprehensive approach to examining such materials should involve an analysis using several complementary methods covering the widest possible range of pore sizes. In addition to the constantly observed increase in the resolution capabilities of devices, the development of computational models and algorithms improving the quality of the measurement signal remains a big challenge

Novel Approach to Tooth Chemistry. Quantification of the Dental-Enamel Junction

The dentin-enamel junction (DEJ) is known for its special role in teeth. Several techniques were applied for the investigation of the DEJ in human sound molar teeth. The electron (EPMA) and proton (PIXE) microprobes gave consistent indications about the variability of elemental concentrations on this boundary. The locally increased and oscillating concentrations of Mg and Na were observed in the junction, in the layer adhering to the enamel and covering roughly half of the DEJ width. The chemical results were compared with the optical profiles of the junction. Our chemical and optical results were next compared with the micromechanical results (hardness, elastic modulus, friction coefficient) available in the world literature. A strong correlation of both result sets was proven, which testifies to the self-affinity of the junction structures for different locations and even for different kinds of teeth and techniques applied for studies. Energetic changes in tooth strictly connected with crystallographic transformations were calculated, and the minimum energetic status was discovered for DEJ zone. Modeling of both walls of the DEJ from optical data was demonstrated. Comparing the DEJ in human teeth with the same structure found in dinosaur, shark, and alligator teeth evidences the universality of dentin enamel junction in animal world. The paper makes a contribution to better understanding the joining of the different hard tissues

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

Exploring academic teachers perspectives regarding the impact of using medical simulation in dentistry pre- and post-COVID-19 pandemic: a qualitative study

Abstract Background Medical simulation allows for the achievement of many educational goals and the continued education of some practical skills. The COVID-19 pandemic’s restrictions have led to a major increase in dental education simulations. The aim of this study was to analyse the perspectives of academic teachers towards dental simulation, their concerns and evaluation of this teaching method, as well as their opinion on the use of medical simulation during the COVID-19 pandemic. Method A focus study was conducted in a group of 5 academic teachers, comprising 10% of academic teachers of a Dental Faculty using simulation techniques. Prior to and during the COVID-19 pandemic, the interviewed teachers had expertise with medical simulation in dentistry education methods. A facilitator used pre-planned, open-ended questions about the use of simulation in dentistry also with regard to the COVID-19 pandemic period. The group discussion has been managed, monitored, and recorded. The data analysis model was based on Braun and Clarke’s six phases of thematic analysis. Five thematic domains/fields were evaluated: (1) Simulation as a didactic method; (2) Simulation during COVID-19 pandemic; (3) General observations and expectations with regard to simulation; (4) Teachers in simulation; (5) Concerns in relation to simulation. Two researchers analysed the data. Results Based on interviewed teachers’ perspective the simulation allows students to learn basic and complex skills providing the repeatability of the procedures performed. During Covid-19 the simulation methods undoubtedly filled the gap in the training of future dentists. However, interviewed teachers pointed out the high cost of the methods dictated by the need to prepare the simulation environment at a high level, in order to reflect the real clinical situation. Conclusions The use of simulation methods requires adequate preparation of academic teachers, continuous education and updating of knowledge in the field of medical simulation. The COVID-19 pandemic significantly influenced the growth of dental education simulation techniques as well as staff knowledge of the usage of medical simulation