Preliminary study of the forces developed by practitioners during amalgam condensation.

The aim of this preliminary study was to analyze, in vitro, the forces developed by practitioners during amalgam condensation. Standardized Class II cavities were drilled into 40 freshly extracted teeth. The forces exerted during condensation were then measured by means of a new device, the Endographe, and plotted online or offline as a function of time on Endogrammes. The work techniques of the different practitioners revealed similarities. The mean values of the vertical forces (+/- SEM) were: 15 +/- 2 N for manual compaction of capsule amalgam; 8 +/- 3 N for manual compaction of amalgam with a higher mercury-to-alloy ratio; 6 +/- 4 N for mechanical compaction of encapsulated amalgam; and 4 +/- 2 N for mechanical compaction of the modified amalgam. For the horizontal components, the forces were, respectively, 5 +/- 2 N, 0.1 +/- 0.05 N, 3 +/- 1 N, and 0.7 +/- 0.2 N. The mean values of condensation time were 20 +/- 15 s for each incremental application, with a great variation in durations between the beginning and end of condensation. By visually depicting forces as a function of time, the Endographe can be used to analyze the process of amalgam insertion and condensation. Future research will study the relationship between the forces developed during condensation and the adaptation of the amalgam to the walls of the cavity.