Knoop hardness test
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Knoop hard·ness num·ber (KHN),(nūp),
a number obtained by dividing the load in kg applied to a pyramidal diamond of specific size divided by the projected area of the impression: KHN = L/A, where A= the projected area of the impression in mm2 and L = the load in kg; used for measurements of hardness of any materials, especially very hard and brittle substances such as tooth dentin and enamel.
Knoop hardness test(noop),
A test of surface hardness, using a stylus with a pyramidal diamond indenter. The long diagonal of the resulting indentation determines the hardness of the substance.
Knoop hard·ness test(knūp hahrdnĕs test)
Dental measurement to determine hardness of brittle materials; uses a diamond or rhombic indenting tool; test result provides dental clinicians with the Knoop hardness number.