Knoop hardness test

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Knoop hard·ness num·ber (KHN),

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

Etymology: Frederick Knoop, 20th century American metallurgist
a method of assessing surface hardness by measuring resistance to the penetration of an indenting tool made of diamond. The test is commonly used for testing the hardness of teeth.

Knoop hardness test



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.
References in periodicals archive ?
In the KNOOP hardness test the modeled shape is an elongated diamond as a result of the indention.
Our results are shown on the selected examples of KNOOP hardness test.
Nyquist, The Measured Knoop Hardness of Hard Substances and Factors Affecting its Determination, Trans.
Titanium diboride has a Knoop hardness of 3400 that is 900 to 1000 points higher than tungsten carbide, so cutting inserts made from titanium diboride fit nicely in a niche above tungsten carbide.
The Mohr or the Knoop hardness scales have been used to compare the hardness of various materials for both materials of construction of the mixer, as well as for the fillers that are being mixed.
DeWald and Ferracane (5) used Knoop hardness (an indentation technique) to study the cure depth of light activated dental composites.
The Knoop hardness number was obtained by the ratio of the load applied to the uncovered projected area of the indentation in [mm.
The Knoop hardness number (KHN) means were subjected to 2-way analysis of variance (ANOVA) and a post-hoc Tukey's test for intergroup comparison.
Dentinal composition and Knoop hardness measurements of cavity floor following carious dentin removal with Carisolv.