dental materials MCQs – Page 11

Practise focused dental materials questions with marked answers for exam preparation and subject revision.

dental materials Mcqs
501. Chemical tempering in porcelains is done to interrupt crack propagation by______________?
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A. Dispersion of crystalline phase

B. Inducing residual compressive strength

C. All of the above

D. Transformation toughening

502. High strength amalgam is achieved by_____________?
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A. Maximum matrix and minimum alloy phase

B. Minimum matrix and maximum alloy phase

C. Minimum alloy phase

D. Maximum matrix phase

503. Copper content in low copper amalgam is________________?
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A. 29%

B. 12-30%

C. 19%

D. 6%
504. Porosity in porcelain can be prevented by_______________?
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A. Rapidity of firing

B. All of the above

C. High firing temperature

D. Thoroughness of condensation
505. Absorption of mercury in the human body occurs least from_____________?
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A. Gastro-intestinal Track

B. Lungs

C. Kidneys

D. Skin

506. What is the most frequently used restorative material ?
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A. Gold

B. Composite

C. Silicate

D. Amalgam
507. Amalgam achieves 70% of the strength by____________?
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A. 16 hours

B. 4 hours

C. 8 hours

D. hours

508. All of the following is used as accelerator in zinc oxide eugenol cement except_____________?
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A. Acetic acid

B. Calcium chloride

C. Zinc acetate dehydrate

D. Bromoglycerine
509. The maximum shrinkage during firing proces in ceramic occurs in__________________?
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A. Low Bisque stage

B. High Bisque stage

C. Fusion stage

D. Medium Bisque stage
510. The melting point of titanium is __________ degree celsius?
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A. 1056

B. 1886

C. 1668

D. 1560

511. Which is the cement with adhesive properties ?
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A. Zinc oxide eugenol

B. Zinc polycarboxylate

C. SIlicate

D. Glass ionomer

E. Both B & D
512. Water of reaction needed to react completely with 100 g of calcium sulphate hemihydrates to convert it to calcium sulphate dihydrate______________?
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A. 22.2ml

B. 18.6ml

C. 30.4ml

D. 45.3ml

513. In spherical alloys as compared to lathe cut____________?
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A. Less condensing force is required

B. More condensing force is required

C. Both require same condensing force

D. Manipulation is easy

514. Compared with dental alloys, CERAMICS show____________________?
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A. Low esthetic value

B. Susceptibility to brittle fracture

C. High hardness

D. High ductility

515. Which component of zinc oxide-eugenol cement gives its strength ?
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A. Rosin

B. Zinc oxide

C. Zinc acetate

D. Oil of cloves

516. MEchanism of adhesion of GIC restoration with tooth surface is by mean of ______________?
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A. C=C double bond

B. Polymer chains

C. Chelates with Metal Ions

D. Carboxyl group
517. The tow cements which hold with the tooth are_______________?
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A. GIC and polycarboxylate

B. GIC and silicate

C. ZnPO4 and silicate

D. GIC and ZnPO4

518. The main components is sillicophosphate cement________________?
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A. Silicate and GIC

B. Zinc phosphate and SIlicate

C. Zinc phosphate and GIC

D. ZOE and Silicate

519. The opacity in ceramics is achieved by adding_______________?
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A. Titanium oxide

B. Silica

C. Copper oxide

D. Boric oxide

520. Increased amount of powder in zinc phosphate cement mixture will cause_______________?
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A. Decreased strength

B. Decreased solubility

C. Decreased film thickness

D. Increased setting time

521. Best marginal seal is provided by____________?
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A. Zinc phosphate

B. Zinc oxide eugenol

C. Gutta-percha

D. Resin

522. When Gold fused with porcelain is fired at very high temperature greenish discoloration of cervical margin is due to________________?
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A. Disintegration of opaque layer

B. High firing temperature

C. Presence of copper

D. Formation of excess oxides

523. Which of the following releases single wavelength of energy ?
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A. QTH

B. PAC

C. Argon lasers

D. LED

524. Which of the following cements bonds to tooth structure, which has an anticariogenic effect, has a degree of translucency and does not irritate the pulp ?
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A. Resin cement

B. Silicate cement

C. Polycarboxylate cement

D. Glass ionomer cement
525. The first porcelain tooth material was introduced by______________?
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A. DeChemant

B. Plateau

C. Ash

D. McClean

526. Mercury is toxic because it_____________?
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A. Binds to sulfhydryl groups

B. Inhibits hemoglobin synthesis, producing anemia

C. Complexes with hemoglobinto form methemoglobin

D. Inhibits anaerobic glycolysis

527. The higher the Hg alloy ratio in dental amalgam________________?
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A. More gamma 1 phase formed

B. Lower the creep value

C. Higher the strength

D. More matrix matrial formed
528. Once triturated, the Dental amalgam should be condensed with in_____________?
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A. 5 minutes

B. 3 minutes

C. 15 minutes

D. 6 minutes

529. The principal constituent of set silicate cement matrix is_______________?
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A. Hydrated Aluminium phosphate crystal, CAF2 alluminosiliate gel

B. Hydrated Aluminium Phosphate with calcium fluoride

C. Hydrate Aluminosilicate gel

D. Hydrated Aluminium phosphate

530. High copper amalgam can be produced_____________?
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A. From smooth atomized particles

B. From irregular and spherical particles

C. From lathe cut particles

D. From traditional alloy particles

531. What is the working time of amalgam?
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A. Five to six minutes

B. Seven to eight minutes

C. One to two minutes

D. Three to four minutes
532. Glass ionomer cements are composed of______________?
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A. Alumino silicate powder and phosphoric acid

B. Zinc oxide powder and polyacrylate liquid

C. Aluminosillicate powder and polyacrylate

D. Zinc oxide powder and phosphoric acid

533. Over-trituration of silver alloy and mercury_______________?
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A. Decreases creep

B. Gives al dull and crumbly amalgam

C. Reduces contraction

D. Increases the strength of lathe cut alloy but reduces the strength of spherical alloy amalgam
534. White gold alloy predominantly is______________?
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A. Gold with silver

B. Gold with much of chromium

C. Gold added with palladium

D. Gold added with calcium

535. The malleting force is directed______________?
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A. None of the above

B. Parallel to long axis of crown

C. Perpendicular to the walls

D. 45 to the wall
536. Torsional force is_______________?
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A. Shear

B. Tensile force

C. Transverse bending force

D. Compression

537. The setting time of ZnPO4 cement can be retarded by_____________?
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A. slower addition of powder to liquid

B. mixing powder to liquid, checked by water

C. faster addition of powder to liquid

D. mixing more powder to the liquid

538. Silicate cement is indicated in________________?
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A. Patients with high caries index

B. In the restoration of posterior tooth

C. Mouth breathers

D. None of the above

539. The logical explanation for the unique anticariogenic property of most silicate cements is______________?
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A. That beryllium flux is used in silicates

B. The reduction in enamel solubility due to fluoride uptake by enamel

C. Due to the high silica content

D. That silicates show very little leakage at the margins of the restoration

540. The best tissue tolerated material for crown and bridge_______________?
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A. Highly polished porcelain

B. Highly glazed porcelain

C. Highly polished acrylic

D. Highly polished metal

541. Frozen slab technique of mixing zinc phosphate is used for_______________?
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A. Temporary dressing

B. Cementing crowns

C. cementing orthodontic bands

D. base

542. Porcelain binds to metal in PFM crown by_________________?
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A. Transparency

B. B and C

C. Chemical bond

D. Metallic bind

543. Dispersion of crystalline phase to strengthen ceramics results in_________________?
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A. dispersed porcelain

B. All of the above

C. Glazed porcelain

D. aluminium porcelain
544. Stage recognized in the firing of dental porcelain given below. Which of state is not correct ?
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A. High bisque

B. Low bisque

C. Medium bisque

D. Cold stage bisque
545. Which of the following is the main constituent of porcelain__________________?
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A. Feldspar

B. Kaolin

C. Quartz

D. Clay

546. The carat for Au foil used for restorations is_______________?
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A. 24

B. 20

C. 18

D. 22

547. The most commonly used, most biocompatible and adhesive cement is______________?
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A. Calcium hydroxide

B. Zinc oxide eugenol

C. Glass ionomer

D. Zinc phosphate

548. Which of the following cements is most biocompatible with pulp ?
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A. Zinc oxide eugenol cement

B. Copper cement

C. GIC

D. Zinc phosphate cement

549. When porcelain is basked against metal, it should possess a________________?
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A. Linear coefficient of thermal expansion greater than, but close to that of the metal

B. high fusion expansion

C. high fusion temperature

D. linear coefficient of thermal expansion less than but close to that of metal
550. Strength of zinc phosphate is effected by_______________?
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A. Consistency of mix

B. Alteration of mixing time

C. P:L ratio

D. Temp of glass slab