Free Restorative Materials MCQs with Answers

• A. Utility wax
• B. Inlay wax
• C. Carding wax
• D. Sticky wax

Explanation: Boxing wax is also called carding wax because it is used to form the wax wall around an impression before pouring the cast.

• A. Paraffin
• B. Carnauba
• C. Canadelila
• D. Gum dammar

Explanation: Gum dammar improves the toughness of inlay wax and reduces its tendency to flake or crumble during carving.

• A. Galvanic current caused by gold onlay occluding with a large restoration
• B. Retained cement in gingival sulcus
• C. Excess acid in mix
• D. Supracocclusion of restoration

Explanation: A sharp shooting pain whenever dissimilar metallic restorations contact can result from galvanic current, with saliva acting as the…

• A. Candellila wax
• B. Paraffin wax
• C. Carnauba wax
• D. Gum dammar

Explanation: Paraffin wax forms the major portion of inlay wax, while harder waxes such as carnauba and candelilla modify its hardness and softening…

• A. Bowen
• B. Buonocore
• C. G.V. Black
• D. William H Taggart

Explanation: William H. Taggart introduced the lost-wax casting technique for cast inlay restorations in 1907.

• A. Make inlay wax patterns
• B. Temporarily cement inlays:
• C. Invest inlay patterns
• D. Box models

Explanation: Inlay wax is a pattern material that is shaped directly or indirectly into the form of the restoration and then invested for casting.

• A. Strength
• B. Expansion components for casting shrinkage
• C. Decrease strength
• D. Contraction

Explanation: Quartz is a refractory component of dental investment and undergoes thermal expansion when heated.

• A. More porous investment in the mould
• B. Hollow sprue pin
• C. Narrow sprue diameter
• D. Large reservoir

Explanation: A narrow sprue restricts the flow of molten alloy and may prevent the mould from filling completely, producing an incomplete casting.

• A. Shrinkage of alloy on cooling
• B. Investment breakdown
• C. Incomplete gas elimination
• D. Incomplete wax elimination

Explanation: Incomplete wax elimination can leave carbon or wax residues that produce a shiny, glossy casting surface and smooth margins.

• A. 700°C
• B. 1,300°C
• C. 1,063°C
• D. 900°C

Explanation: Gypsum-bonded investments should generally not be heated above about 700°C because the gypsum binder decomposes at higher temperatures and…

• A. Decrease flow
• B. Continuous expansion
• C. Relaxation of the internal stresses
• D. Water loss

Explanation: Wax patterns contain internal stresses that gradually relax, causing distortion if investing is delayed.

• A. Impressions
• B. Casts
• C. Die
• D. Casts and Dies

Explanation: Gypsum products are mainly used to make positive replicas of oral structures, including study casts, working casts and dies.

• A. Regulate setting time
• B. To regulate the setting expansion
• C. Acts as retarder
• D. None

Explanation: Potassium sulfate acts as an accelerator in gypsum, so its main role is to regulate or shorten the setting time.

• A. Slower the hygroscopic expansion
• B. Greater the hygroscopic expansion
• C. Normal setting expansion
• D. No setting expansion

Explanation: Finer silica particles provide greater surface area and promote more interaction with the setting material, increasing hygroscopic…

• A. 1
• B. 4
• C. 12
• D. 25

Explanation: Gypsum products are covered under ADA Specification No. 25, which includes dental plaster, stone, and improved stone.

• A. Modify strength
• B. Modify setting expansion
• C. Modify setting time
• D. Decrease the porosity

Explanation: Modifiers are added mainly to control the setting reaction, especially by accelerating or retarding setting time.

• A. H2O interferes with hygroscopic expansion
• B. H2O inhibits polymerization of dental resin
• C. H2O interferes with Crystallization of dihydrate
• D. Gypsum is slightly soluble in water and the surface of the cast will be eroded

Explanation: Gypsum is slightly soluble in water, so running tap water can dissolve and erode the cast surface.

• A. They are more irregular in shape and porous
• B. They are more regular in shape and highly porous
• C. They are more regular in shape and dense
• D. They are more dense and prismatic in shape

Explanation: Beta hemihydrate particles are irregular and porous, giving them a larger surface area and requiring more water to wet and separate them.

• A. Altering P / L Ratio
• B. Addition of accelerators and retarders
• C. Speed and length of hand spatulation
• D. Altering temperature of mixing water

Explanation: The most controlled way to alter plaster setting time is by adding accelerators or retarders.

• A. Stone
• B. Plaster
• C. Investment
• D. All of the above

Explanation: Plaster and stone are gypsum products, while investment is a gypsum product when it is gypsum-bonded and contains gypsum as its binder.