Kerala University 2009 B.D.S Dental Surgery , 3, Dental materials - Question Paper

Essay :
I. describe dental composite. Classify dental composite and write in detail on the
composition of a dental composite. (1+2+7)
II. kinds of abrasives used in dentistry. Add a note on the composition of a typical
dentrifice. (6+4)
Short notes : (5×3=15 Marks)
1. Glass ionomer cement – composition, setting reaction, and mechanism of adhesion
to tooth.
2. Phosphate bonded investment.
3. Factors affecting strength of dental amalgam.
Multiple option ques. : (15×1=15 Marks)
1. Eutectic alloy temperature is
a) 649° C b) 779° C
c) 500° C d) 1400° C

2. If the usage test is performed in humans it is called
a) clinical trial
b) level I test
c) level IV test
d) sensitization test
3. Aluwax contains
a) copper
b) silica
c) aluminium
d) zinc oxide
4. In a casting, subsurface porosity can be diminished by controlling the
a) mould temperature
b) sprue length
c) melt temperature
d) rate at which the molten metal enters the mould
5. Procedure which is used to shape the abrasive instruments as well as to remove
clogged debris from the instrument
a) truing
b) dressing
c) sintering
d) buffing -3- 1725
6. Sandwich technique of restoration uses
a) amalgam and glass ionomer
b) polycarboxylate and glass ionomer
c) composite and glass ionomer
d) only composite
7. Radiant energy needed for maximum curing of a two mm thick layer of resin is
a) 16 milli joules / cm2
b) 16,000 milli joules / cm2
c) 1600 milli joules / cm2
d) 160,000 milli joules / cm2
8. Enamel bonding agents are used
a) to enhance the wettability of etched enamel
b) to increase the adhesion of composite to enamel
c) to increase the tag length
d) to improve chemical bonding
9. Setting time of zinc phosphate cement can be retarded by
a) diluting the liquid with small amounts of H2
O
b) accelerating the rate of addition of powder to liquid
c) increasing the ratio of powder to liquid
d) decreasing the rate of addition of powder to liquid
10. Cavity varnish is a material which
a) develops an impermeable resin film
b) develops semipermeable membrane of resin film
c) is a calcium hydroxide powder in an aqueous medium
d) is a eugenol solution in an organic solvent11. E-Z gold is a kind of
a) gold foil
b) crystalline gold
c) powdered gold
d) fibrous gold
12. 24 hour compressive strength is highest for
a) zinc phosphate cement

Earning:   Approval pending.