The Impact of ZnO Nanofillers on the Mechanical and Anti-Corrosion Performances of Epoxy Composites.

Epoxy resins were reinforced with different ZnO nanofillers (commercial ZnO nanoparticles (ZnO NPs), recycled ZnO and functionalized ZnO NPs) in order to obtain ZnO-epoxy composites with suitable mechanical properties, high adhesion strength, and good resistance to corrosion. The final properties of ZnO-epoxy composites depend on several factors, such as the type and contents of nanofillers, the epoxy resin type, curing agent, and preparation methods. This paper aims to review the preparation methods, mechanical and anti-corrosion performance, and applications of ZnO-epoxy composites.

Endodontic Dentistry: Analysis of Dentinal Stress and Strain Development during Shaping of Curved Root Canals.

Background: Endodontic shaping causes stress and strain in the root canal dentin. Dentin microcracks have the potential to be later followed by root fractures occurring under the occlusal load. The aim of our research was to theoretically determine the values of such dentinal states of stress and strain during the endodontic shaping of curved root canals using finite element analysis (FEA).

Influence of the Thermal Environment on Occupational Health and Safety in Automotive Industry: A Case Study.

Considering thermal environment aspects have a major impact not only on occupational health and safety (OH&S) performance but also on the productivity and satisfaction of the workers, the aim of the case study was to assess the thermal comfort of a group of 33 workers in an automotive industry company, starting with collecting data about the thermal environment from different workplaces, continuing with the analytical determination and interpretation of thermal comfort using the calculation of the Predicted Mean Vote () and Predicted Percentage of Dissatisfied () indices, according to provisions of the standard ISO 7730:2005, and comparing the results with the subjective perception of the workers revealed by applying individual questionnaires. The results of the study represent an important input element for establishing the preventive and protective measures for the analysed workplaces in correlation with the measures addressing other specific risks and, also, could serve as a model for extending and applying to other similar workplaces in future studies. Moreover, the mathematical model and the software instrument used for this study case could be used in further similar studies on larger groups of workers and in any industrial domain.

Microscopic morphological changes of the tooth surface in relation to fixed orthodontic treatment.

Orthodontic treatment has, as any other medical intervention, in addition to its benefits, side effects, some of them being perceived as unavoidable. The aim of this case series was to microscopically evaluate the changes of the tooth surface in relation to fixed orthodontic treatment. A case series study was implemented by the usage of four extracted first maxillary premolars, from patients with previous orthodontic treatment, of 12 and 23 months.

Masticatory tensile developed in upper anterior teeth with chronic apical periodontitis. A finite-element analysis study.

Commonly is accepted that a non-vital tooth has a higher risk of root fracture but there is a relatively little knowledge about the specific biomechanical behavior of non-vital frontal teeth with chronic apical periodontitis. The aim of our study was to evaluate the deformation and tensile generated in these teeth while vertically loading them because it is crucial to assess the moment when the absorbed occlusal forces exceed the elasticity of root dentine. Using the method of finite-element analysis, we highlighted the distribution patterns of the compressive and tension tensile, as well as their concentration areas.