CONDENSATION PRESSURE DURING AMALGAM PLACEMENT IN PATIENTS

The purpose of this study was to investigate the condensation pressure during amalgam placement in patients. Forty-four practitioners were a sked to fill two class 2 cavities in the lower jaw on their patients i n their own practice with the aid of a force-measuring plugger. This d evice, with semiconductor strain gauges, allowed the dentist to have a n identical tactile feedback as with any other plugger. Three differen t amalgams, with different shapes of alloy particles, were tested. The results showed a maximum condensation pressure of 8.9 +/- 2.4 MPa and 5.5 +/- 1.8 MPa with a small and a large amalgam plugger, respectivel y. Average condensation pressures were 3.7 +/- 1.3 MPa for the small a nd 2.2 +/- 0.9 MPa for the large instrument. The total working time re quired to fill a cavity was on average 131 s; the amalgam was effectiv ely condensed for 44 s. No significant differences between amalgams wi th different shapes of alloy particles, no influence of time of day, a nd no difference between female and male dentists were found. This stu dy showed that the condensation pressure is lower than often recommend ed, and that it is not statistically different from the values obtaine d in a previous laboratory study (1).