The clinical characteristic selected for this test was the "limit of carvability," the amalgam consistency at which the dentist feels that further carving embodies an excessive risk of fracture. A punch test approximating pure shear loading was selected to measure this property. Results of hand-carving tests made on specimens indicate that the clinical limit of carvability is approximated closely by that time at which the load required for punching is 25.5 lb.
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