In processing methyl methacrylate, the resin may show porosity if the flask is placed too soon porosity most likely occur_____________?

Related Mcqs:

1. Polymerisation of heat-cured methyl methacrylate is initiated by______________?

   A. Tertiary amine
   B. Benzoyl peroxide free radical
   C. Hydroquinone
   D. Methyl ether

2. The advantage of unfilled methyl methacrylate is that______________?

   A. It can be finished smoothly
   B. It has a low degree of flow
   C. It’s non-irritation to pulp
   D. It’s wear resistant is high

3. Hydroquinone is added to methyl methacrylate monomer_________________?

   A. To prevent polymerization during storage
   B. To initiate release of free radicalls
   C. To enable polymerization reaction at room temperature
   D. All of the above

4. The accepted polymer to monomer ratio for packing of polymethyl methacrylate resin is____________?

   A. 3:1
   B. 4:1
   C. 10:1
   D. 5:1

5. Along with polymerisation shrinkage, one of the major disadvantages of polymethyl methacrylate as denture base resin are its poor_____________?

   A. Biological properties
   B. Thermal properties
   C. Mechanical properties
   D. Esthetic properties

6. One of the claims for the superiority composite resin restoration over silicate cement restorations is that the resin restorations_____________?

   A. Prevent galvanic action
   B. Are practically insoluble in oral fluids
   C. Adapt to the walls of the cavity better
   D. Have a higher coefficient of thermal expansion

7. To prevent porosity in self-cure acrylic resin, curing should be carried in______________?

   A. Cold water
   B. Hot water
   C. Under tap water
   D. Under vacuum pressure

8. Benzoin methyl ether in a polymer indicates that they may be cured in the presence of________________?

   A. UV light
   B. Visible light
   C. Infrared light
   D. Diketone

9. Which of the following may result if an excessive amount of monomer is incorporated into an acrylic resin mixture ?

   A. Excessive expansion
   B. Low impact strength
   C. Excessive shrinkage
   D. Excessive brittleness

10. Which of the following is NOT true of polymethyl methacrylate ?

    A. Knoop hardness number 18 to 20
    B. Tensile strength of 60 MPa
    C. Density of 1.13 g/cm3
    D. Modulus of elasticity of 3.4 GPa