Fracture toughness measurement of dental ceramics using the indentation fracture method with different formulas.

This study examined fracture toughness (KIC) measurements obtained using the indentation fracture (IF) method with a view to improving their reliability. The KIC values of five dental ceramics were measured using the IF method with five different formulas, and the single-edge precracked beam (SEPB) method was used as a control. The elastic moduli of the dental ceramics were evaluated by dynamic hardness test.