NEET MDS Shorts
743912
Dental MaterialRepair of denture bases should be carried out with cold-cure resins in order to avoid distortion of the denture base
276977
Dental MaterialWater interferes with chemical adhesion of the polycarboxylate cement to enamel
704351
Dental MaterialThe working time for a polysulfide impression material can be safely and effectively increased by cooling the mixing slab to a temperature above the dew point
482940
Dental MaterialThe Vickers hardness test is the most suitable for materials that exhibit
elastic recovery. The Vickers hardness test involves the use of a diamond
indenter in the form of a pyramid with a square base. The test applies a
controlled load to the specimen and measures the depth of the resulting
indentation. It is a micro-indentation hardness test, meaning it is used for
small or thin sections or for precise measurements. This test is particularly
useful for brittle materials, such as ceramics, because it creates a very small
indentation and applies a relatively low load compared to the other methods.
The other options are not as suitable for materials with elastic recovery for
the following reasons:
2. Brinell hardness test: This test uses a spherical indenter, usually a hard
steel or tungsten carbide ball, to press into the material with a significant
load. It is typically used for softer materials and is not as precise for small
indentations or for materials that are prone to plastic deformation, which may
affect the accuracy of the elastic recovery measurement.
3. Knoop hardness test: Similar to the Vickers test, the Knoop test uses a
diamond indenter but in the shape of a rhombic pyramid. Although it is also a
micro-indentation test, the Knoop indenter has a more pointed tip compared to
the Vickers pyramid. This can make it less ideal for certain materials that
exhibit elastic recovery since the sharp tip can cause more plastic deformation
and potentially damage the material.
While all three tests can be used to measure the hardness of materials, the
Vickers test is generally considered the best for materials that exhibit elastic
recovery due to its ability to produce precise and reliable results with minimal
plastic deformation.
791993
Dental Material
The sprue former should be attached to the wax pattern at the area of more bulk
323426
Dental Material
GIC has an anticarious anticariogenic effect,
It binds to tooth structure, Does not irritate the pulp tissue
675564
Dental MaterialPolycarboxylate cement is a luting agent that provides adhesion to calcified dental tissues
890189
Dental MaterialFusion Temperature of Impression Compound should occur above mouth temperature