[The problem of standards for composites]

The bending strenght to the breakage point was determined for five different composites. The testing instrument was set up in accordance with standard specifications under application of pressure. It could be established that the bending strength to the breakage point depends on the intensity and duration of the force. Values were 10% to 20% higher than with polymerized samples without pressure. Long-term studies carried out approximately 24 hours after the sample had been produced showed the highest values for bending strength to the breakage point. These values dropped about 20% during the course of 8 to 10 days. The influence of storage conditions was also determined. In these tests, the bending strength to the breakage point dropped 20% to 30% after 24 hours.