Free Restorative Materials MCQs with Answers

• A. 300 mw/sm2
• B. 350 mw/cm2
• C. 400 mw/cm2
• D. 450 mw/cm2

Explanation: A quartz-tungsten-halogen curing unit should provide at least about 300 mW/cm² to polymerize composite adequately.

• A. Low compressive strength
• B. High water absorption
• C. High abrasive resistance
• D. High polymerization shrinkage

Explanation: Inorganic fillers give composite resin greater resistance to abrasion than unfilled acrylic resin.

• A. Zinc oxide
• B. Methyl methacrylate
• C. Phosphoric acid
• D. Eugenol

Explanation: Phosphoric acid selectively dissolves the superficial mineral of enamel, creating microporosities for micromechanical bonding.

• A. Is fiber optic
• B. Need no protection while in use
• C. Will cure composite upto a depth of 5 millimeter thickness
• D. Should be held at a millimeter distance from the restoration

Explanation: The curing tip should be held very close, approximately 1 mm from the restoration, because light intensity falls rapidly with distance.

• A. Amalgam alloy
• B. Unfilled resin
• C. Composite resin
• D. Direct filling gold

Explanation: Unfilled resin has a relatively high coefficient of thermal expansion, so temperature changes produce greater dimensional mismatch and…

• A. Increased thermal conductivity
• B. Decreased thermal conductivity
• C. Decreased wear resistance
• D. None of the above

Explanation: Composites generally have lower wear resistance than amalgam, particularly in high-stress or posterior applications.

• A. Increasing the mechanical strength
• B. Decreasing the coefficient of thermal expansion
• C. Reducing the polymerization shrinkage
• D. All of the aboveConsult Online Doctors

Explanation: The inorganic filler strengthens the composite, lowers its coefficient of thermal expansion, and replaces some resin volume, thereby…

• A. Polymerization shrinkage is greater if bonded surface area is lesser than unbounded surface area
• B. Polymerization shrinkage is high if within the enamel margins
• C. Acid etching and priming will decrease polymerization shrinkage
• D. Microleakage can occur because of polymerization shrinkageTry Prep Courses

Explanation: Polymerization shrinkage causes greater stress when the bonded surface area is large relative to the free, unbonded surface area, not when…

• A. TEGDMA
• B. Ti02
• C. BIS-GMA
• D. None of the above

Explanation: Titanium dioxide is an opaque pigment that masks the underlying tooth structure and gives composite its opacity.

• A. 30 seconds
• B. 60 seconds
• C. 90 seconds
• D. 120 seconds

Explanation: The conventional enamel acid-etching time is about 30 seconds, which produces microporosities for resin retention.

• A. BIS GMA
• B. Polymethyl methacrylate
• C. Benzoin methyl ether
• D. Silica filter

Explanation: Bis-GMA is a common dimethacrylate resin monomer in composite resins, many bonding agents, and resin-based occlusal sealants.

• A. Silica glass
• B. Barium glass and strontium glasses
• C. Organic matrix
• D. Fluoride particles

Explanation: Barium and strontium glasses contain high-atomic-number elements that absorb X-rays and make composite radiopaque.

• A. 90
• B. 343
• C. 67
• D. 450

Explanation: Dental amalgam has a Knoop hardness of approximately 90 KHN in commonly cited dental-materials tables.

• A. 50 - 60 KHN
• B. 40 - 48 KHN
• C. 15 - 20 KHN
• D. 25 - 35 KHN

Explanation: Microfilled composites contain smaller and less heavily loaded filler particles, giving them a lower Knoop hardness than hybrid…

• A. Investment
• B. Models
• C. Casts
• D. Dies

Explanation: Investment expansion is useful because it compensates for the solidification shrinkage of the casting alloy.

• A. Using asbestos linear
• B. Placing the sprue at least one quarter inch away form the end of casting ring
• C. Preventing rapid heating the investment in burnout oven
• D. Using a short and wide sprue

Explanation: Back-pressure porosity results when air or gases cannot escape from the mold as molten alloy enters it.

• A. Produce a smoother casting
• B. Increase setting expansion
• C. Decrease setting expansion
• D. Increase thermal expansion

Explanation: A thinner gypsum investment mix contains more water, which increases porosity after drying and reduces the effective gypsum concentration.

• A. Gypsum
• B. Silica content
• C. Carbon content
• D. Copper

Explanation: The gypsum binder is the principal source of strength in a gypsum-bonded investment, while silica mainly provides refractory behaviour and…

• A. Type 1
• B. Type 2
• C. Type 3
• D. Type 4

Explanation: Type I inlay wax is intended for the direct technique, where the wax pattern is formed directly in the prepared tooth.

• A. Gypsum bonded
• B. Phosphate bonded
• C. Silica bonded
• D. None of the above

Explanation: Cobalt-chromium alloys melt at high temperatures, so gypsum-bonded investments cannot withstand casting temperatures reliably.