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

Electromagnetic field in human environment and method of its determination

W artykule przedstawione zostały główne źródła pól elektromagnetycznych oraz skala zagrożeń i ochrona przed tymi polami. W drugiej części artykułu przedstawiono natomiast metody pozwalające na graficzną interpretację pól elektromagnetycznych występujących w otoczeniu linii napowietrznych. Naturalne natężenie pola elektrycznego przy powierzchni Ziemi w warunkach dobrej pogody ma wartość od 100 do 150 V/m. Z kolei w warunkach burzy może dochodzić do około 20 kV/m. Wartości naturalnego pola magnetycznego zależne są od szerokości geograficznej i mogą zawierać się w przedziale od 20 do 60 A/m. Do źródeł pól elektromagnetycznych (PEM) zaliczyć można wszystkie urządzenia i instalacje elektryczne, które użytkowane są w energetyce, w przemyśle, w budynkach mieszkalnych i użyteczności publicznej, jak również w transporcie.Paper presents examples of sources of electromagnetic fields and possible dangers involved. Last chapters of paper presents methods leading to graphical interpretation of fields around high-voltage lines. Natural intension of electric field over Earth assumes value of 100-150 [V/m] but by thunderstorm reaches 20 [kV/m]. Earth's magnetic field is optimal for existence of life and its growth. The magnetism of earth reaches 47 [µT]. Live organisms induces a slight magnetic field, that is contrary the magnetic field of the earth. There are many sources of electromagnetic fields, electric installations used in buildings, industry, transport, and wide range of house devices