the results of the initial study. It was concluded that the apical fluids, with their primary source being blood serum, diffuse into the empty canal spaces, stagnate, undergo degradation and then act as a physicochemical irritant when they diffuse back into periapical tissues. In support of this theory of stagnation, in 1955 Dow and Ingle showed that the majority of the endodontic failures were...

introduction:  this  in vitro  study compared the apical sealing ability of three common root end filling materials namely mineral trioxide aggregate (mta), intermediate restorative material (irm) and calcium-enriched mixture (cem) cement using a bacterial leakage model.  methods and materials: the study was conducted on 83 single-rooted human teeth. tooth crowns were cut and root canals were p...

background and aims. the most common method for alginate impression disinfection is spraying it by disinfecting agents, but some studies have shown that these impressions can be immersed, too. the aim of this study was to evaluate the dimensional stability of alginate impressions following disinfecting by spray and immersion methods. materials and methods. four common disinfecting agents (sodiu...

objectives: this study aimed to evaluate the effect of storage period on dimensional stability of alginplus and hydrogum 5. materials and methods: in this in vitro experimental study, 60 impressions were taken of an upper jaw typodont, including 10 impressions for each storage period to be tested (12 minutes, 24 and 120 hours) for each type of alginate. then, the impressions were stored in an i...

some manufacturers claim to have produced new irreversible hydro-colloids that are able to maintain their dimensional stability during storage. the present study evaluated the effect of storage time on dimensional stability of three alginates: hydrogum 5, tropicalgin and alginoplast.in this experimental in-vitro trial, a total of 90 alginate impressions were made from a dentoform model using hy...

conclusions within the limitations of this study, disinfectants were able to completely eliminate microorganisms carried by the alginate impressions. however, more efficient disinfection methods are needed to eliminate the risk of cross contamination by condensational silicone impressions. background dental impressions often carry microorganisms that may cause cross-infection from patients to d...

The nonlinear dynamic model of rotor-bearing-seal system with crack in shaft is set up based on the coupling model of nonlinear oil-film force and Muszyska’s nonlinear seal fluid force. The dynamic vibration characteristics of the rotor-bearing-seal system and the effects of physical and structural parameters of labyrinth seal and crack fault on movement character of the rotor were analyzed. Th...

T is estimated that there are several differences between elder and younger people on cognitive and behavioral characteristics toward anthropomorphized artifacts such as robots and animation characters on screens. Robots are expected as one of assistive technologies in home for the elderly, in particular, in industrialized countries including Japan, due to the decrease in rates of childbirth an...