Comparison of digital and conventional impression techniques: evaluation of patients’ perception, treatment comfort, effectiveness and clinical outcomes

Background: The purpose of this study was to compare two impression techniques from the perspective of patient preferences and treatment comfort.Methods: Twenty-four (12 male, 12 female) subjects who had no previous experience with either conventional or digital impression participated in this study. Conventional impressions of maxillary and mandibular dental arches were taken with a polyether impression material (Impregum, 3 M ESPE), and bite registrations were made with polysiloxane bite registration material (Futar D, Kettenbach). Two weeks later, digital impressions and bite scans were performed using an intra-oral scanner (CEREC Omnicam, Sirona). Immediately after the impressions were made, the subjects' attitudes, preferences and perceptions towards impression techniques were evaluated using a standardized questionnaire. The perceived source of stress was evaluated using the State-Trait Anxiety Scale. Processing steps of the impression techniques (tray selection, working time etc.) were recorded in seconds. Statistical analyses were performed with the Wilcoxon Rank test, and p < 0.05 was considered significant.Results: There were significant differences among the groups (p < 0.05) in terms of total working time and processing steps. Patients stated that digital impressions were more comfortable than conventional techniques.Conclusions: Digital impressions resulted in a more time-efficient technique than conventional impressions. Patients preferred the digital impression technique rather than conventional techniques

Changes of random vitrinite reflectance of coalified organic matter in the Istebna Beds as evidence of tectonic evolution of the Silesian nappe (western flysch Carpathians)

Organic matter in the Istebna beds occur as dark laminas in sandy mudstones. Coalification degree of organic matter in the Istebna beds is related with orogenic period of the flysch Carpathians. There is no correlation with age of rocks and subsidence processing started during Paleogene. Higher values of vitrinite reflectance in southern part of Silesian Unit have been noticed

Possible interactions between stent and electromagnetic field

Over the past years, an increase in the amount of the electromagnetic sources could be observed. Model presented in this article is limited to the impact of low frequency fields generated by the e.g. electrical power lines or magnetic coils in a bone fractures therapy. Particularly, the effect of the magnetic component of the electromagnetic field on stents will be evaluated. The conductivity of human tissues will be investigated. Yielded results will be used to simplify complicated, three-dimensional problem of the current distribution in stent branches, to one-dimensional one. The merits of the paper is proposing, implementing and using for analysis a numerical model of the stent in magnetic field. The impact of frequency and positioning of stent in the magnetic field will be investigated and current distributions found