Fundamental studies of impression method. Part 3 Seating speed and holding pressure of impression tray.

In construction of the full denture, it is important for the improvement of masticatory function and prevention of injury to the soft tissue to explicate the relationship between the impression methods and contour variations of the master cast.In this study, the impression pressure is devided between the seating speed and holding pres. sure of the impession tray, and the three dimensions repositioner and simulation model as the edentulous alveolar ridge are used for impression in the denture construction. It is investigated with three dimensional measurement of the master cast and pressure distribution in the impression tray measured by the diaphragm pressure sensor that the seating speed and holding pressure are influenced on the reproductivity of simulation model.As the result of this investigation, it is revealed that the seating speed and holding pressure of impression tray influence contour variations of the master cast irrespective of displaceability of impression objective. But when the soft tissue as impression objective has large displaceability, it is necessary to consider the form and location of the stopper and holding pressure of impression tray, because of deformation of stopper area according to holding pressure.