[The tensile strength of amalgam after 15 minutes].

The authors are mainly interested in the investigation of the tensile strength of a setting amalgam acquired after 15 minutes after the end of the trituration. Knowledge about this property is of interest because generally this moment corresponds with the time that a patient is asked to put the amalgam restoration into contact with the antagonist tooth. In two series of experiments eight commercial amalgam alloys, two different trituration techniques (hand and Silamat mixing machine) as well as two condensation techniques (hand and Bergendal vibrator) were tested. The reslts reveal that the tensile strengths of the different treatment combinations of amalgams prepared from Dispersalloy are significantly much higher than the minimum value of 2 MN/m2 which is required by the new stipulations of the A.D.A. specification n degrees 1. Some amalgams do not satisfy this requirement. Although the influence of the trituration technique as well as that of the condensation technique turns out to be significant, apparently the influence of the amalgam alloy is of much greater importance.