A new method to measure the condensation pressure of amalgam under in vivo conditions.

The purpose of this study was to investigate the condensation pressure of amalgam achieved under close to in vivo conditions by 42 general practitioners who were asked to fill a pre-cut standard class 2 cavity in a mannequin head. A measuring device was designed to allow the maximum and average condensation pressures and working and resting periods to be obtained. The results showed a maximum condensation pressure of 9.17 +/- 3.04 MPa and 4.09 +/- 1.41 MPa with a small (diameter, 1.15 mm) and a large (diameter, 1.8 mm) amalgam plugger, respectively. Only one of the 42 dentists reached the recommended condensation pressure of 15 MPa (Jørgensen, 1977). A significant (p less than or equal to 0.001) correlation between the duration of the working periods and the maximum condensation pressure was found (r = 0.61). Further investigations are required to determine the influence of these different condensation pressures on the physical properties of various amalgams.