All Free Dental Materials MCQs with Answers

• A. Proportional limit
• B. Ultimate tensile strength
• C. Modulus of elasticity
• D. Flow

Explanation: Stiffness is resistance to elastic deformation and is measured by the modulus of elasticity.

• A. Ternary alloy
• B. Eutectic alloy
• C. Peritectic allowy
• D. Solid solution

Explanation: A solid solution is considered the simplest alloy because atoms of one element are uniformly dissolved in the crystal lattice of another.

• A. 960° Centigrade
• B. 1063° centigrade
• C. 850° Centrigrade
• D. 1123° Centrigrade

Explanation: Silver melts at about 960.8°C, usually rounded to 960°C in dental-materials MCQs.

• A. Vickers's hardness number
• B. Brinell hardness number
• C. Knoop hardness number
• D. Rockwell hardness number

Explanation: For gold alloys, Brinell hardness correlates with strength and can be used to estimate the proportional limit indirectly.

• A. Green flame
• B. Oxidizing flame
• C. Reducing flame
• D. All of the above

Explanation: The reducing zone of the flame is used for melting casting alloys because it limits oxidation of the molten metal.

• A. Sand blasting with aluminium oxide
• B. Cold HF
• C. Cold H2SO4
• D. Warm HCI

Explanation: Cast base-metal alloys are commonly cleaned by sandblasting with aluminium oxide, which removes investment remnants and surface oxides…

• A. a titanium
• B. Nickel-titanium
• C. Chrome-cobalt-nickel
• D. B titanium

Explanation: Nickel-titanium has a low elastic modulus and a very large elastic or superelastic range, allowing substantial recoverable deformation.

• A. Tempering
• B. Age hardening
• C. Work hardening
• D. Precipitation hardening

Explanation: Orthodontic stainless-steel wire is strengthened mainly by work hardening, produced when cold working increases dislocation density.

• A. Is accomplished by soaking the casting in baking soda
• B. Causes porosity in gold
• C. Remove investment from gold casting
• D. Removes surface oxides from gold castings

Explanation: Pickling uses an acidic solution to dissolve surface oxides and tarnish from a casting, particularly after heating.

• A. Austenite
• B. Ferrite
• C. Martensite
• D. Pearlite

Explanation: 18-8 stainless steel is predominantly austenitic because its chromium-nickel composition stabilizes the face-centred cubic austenite…

• A. Inlay wax type-II
• B. Casting wax
• C. Modelling wax
• D. Boxing wax

Explanation: The metal framework pattern of a removable partial denture is made with casting wax, often using prefabricated wax sheets and forms.

• A. 0.4%
• B. 1.4%
• C. 2.4%
• D. 3.4%

Explanation: Gold casting alloys undergo about 1.4% linear contraction on solidification, although the exact value varies with alloy composition.

• A. Cobalt-chrome alloys
• B. Palladium alloys
• C. Wrought alloy
• D. Partial denture casting gold in hardened condition

Explanation: Rigidity for frameworks of identical dimensions depends mainly on the modulus of elasticity.

• A. Molybdenum
• B. Titanium
• C. Germanium
• D. Chromium

Explanation: Titanium can be copy milled as a relatively economical alternative to composite and ceramic materials, especially for dental frameworks…

• A. Alpha form
• B. Gamma form
• C. Beta form
• D. None of the above

Explanation: Austenite is the face-centred cubic, gamma-phase solid solution of carbon in iron.

• A. Carats
• B. Percentage
• C. Fineness
• D. Gram

Explanation: Gold purity in dental alloys is commonly stated as fineness, meaning parts of pure gold per 1,000 parts of alloy.

• A. Austenite to ferrite
• B. Martensite to austenite
• C. Ferrite to austenite
• D. Austenite to martensite

Explanation: When stressed below its transformation temperature, NiTi changes from austenite to stress-induced martensite, allowing temporary…

• A. All of the above
• B. Hygroscopic expansion
• C. Wax expansion
• D. Thermal expansion

Explanation: Casting alloy contraction is offset by expansion of the wax pattern and investment, including thermal and hygroscopic expansion.

• A. 55
• B. 65
• C. 75
• D. 85

Explanation: Under ADA Specification No. 5, dental gold casting alloys contain at least 75% gold plus platinum-group metals.

• A. Annealing
• B. Degassing
• C. Conditioning
• D. Pickling

Explanation: Pickling uses an acid solution to dissolve surface oxides and other contaminants from a casting after removal from the investment.