Effects of specimen geometry on the measurement of fracture toughness

The objective of this study was to investigate the use of compact test specimen geometries of reduced size for the measurement of fracture toughness, KIc, of dental resin composites. Provisional fracture toughness values were determined for four dental composites by use of a reduced-size compact test specimen. The specimens were volumetrically 8% of the size of compact test specimens used in previous studies on dental composites. The test results and conditions met validity tests. These results were compared with those from previous studies that used large compact test specimens. It is concluded that the reduced-size compact test specimen is an acceptable alternative for measurement of fracture toughness.