811. Which of the following hardness tests uses a hardened steel ball indenting tool?
A. Rockwell hardness test
B. Vickers hardness test
D. Knoop hardness test
E. Bierbaum hardness test
812. The green strength of a gypsum product refers to its?
A. wet strength
B. actual strength
C. dry strength
D. apparent strength
813. Which of the following would retard the setting reaction of zinc oxide -eugenol?
B. High humidity
C. Glacial acetic acid
D. Primary alcohols
E. None of the above
814. The cross linking reaction of poly-sulfide elastomers can be made more effective by the addition ofasmall amount of
815. The sprue former should he attached to the wax pattern?
A. on a flat surface
B. in an area where the anatomy is not critical
C. at the thinnest point
D. on any proximal surface
E. at the point of greatest bulk
816. The film thickness for a luting cement should not be greater than?
A. 100 micrometer
B. 1.5 um
C. 25 um
D. 500 um
817. In PFM (porcelain fused to metal) restorations, the porcelain bonds to metal by?
B. chemical bonding
C. compressive bonding
D. a11 of the above
818. What should be the relation of the modulus of elasticity of a cement base and that of therestorative material?
A. There is no relation at all
B. The restorative material must have a higher modulus
C. The cement base must have a higher modulus
D The modulus must be equal
819. The property of flow is most important in?
B. zinc oxide -eugenol cements
D. gold alloys
820. Whenliquefying agar hydrocolloid gel. it should not be boiled for more than 10 minutes, as thismay result in?
A. decrease in strength
B. incorporation of undesirable stresses
C. leaching out of the plasticizer
D. all of the above
E none of the above