All Free Dental Materials MCQs with Answers

• A. Condensation silicone
• B. Alginate
• C. Polysulfide
• D. Addition silicone

Explanation: Polysulfide has the greatest tear strength among the common elastomeric impression materials, making it more resistant to tearing in thin…

• A. Provides gel strength
• B. Acts as an accelerator
• C. Initiating the setting reaction
• D. increasing the working time of alginate impression material

Explanation: Trisodium phosphate reacts preferentially with calcium ions and delays formation of the alginate gel, thereby increasing working time.

• A. Agar
• B. Alginate impression material
• C. Primary impression
• D. Both of the above

Explanation: Agar syringe material is the low-viscosity component used with agar tray material and can also be combined with alginate in a combination…

• A. Low thermal conductivity
• B. High flow property
• C. Degradation is presence of moisture
• D. Remain distortion free up to 72 hrs. pouring can be safely delayed

Explanation: Impression compound has low thermal conductivity, so it takes time to soften and cool.

• A. Mercaptan
• B. A and B
• C. Reversible hydrocolloid
• D. Silicone

Explanation: Heavy- and light-body consistencies are used in elastomeric systems, including polysulfide, formerly called mercaptan, and silicone…

• A. Increase gel strength
• B. Prevent syneresis
• C. Wash off saliva on impression
• D. Prevent distortion

Explanation: Washing an elastic impression removes saliva, blood and other surface contaminants before the cast is poured.

• A. alginate
• B. Alginic acid
• C. Gelatin
• D. Agar

Explanation: Agar is the principal gel-forming constituent of reversible hydrocolloid impression material.

• A. Hydrocolloids
• B. Impression plaster
• C. Elastomer
• D. Impression compound

Explanation: Hydrocolloids undergo a reversible sol-to-gel transformation: heating converts the gel to sol and cooling converts it back to gel.

• A. Reversible hydrocolloid
• B. Mercaptan impression material
• C. Zinc Phosphate cement
• D. Zinc oxide-eugenol

Explanation: Vulcanization is the cross-linking process used to set mercaptan, or polysulfide, impression material.

• A. Oral mucosal tissues
• B. Dental hard tissues
• C. Oral mucosal tissues and dental hard tissues
• D. None of the above

Explanation: An impression records both the oral soft tissues, such as mucosa, and hard tissues, such as teeth and prepared surfaces.

• A. Gelation
• B. Water absorption
• C. Shrinkage
• D. Seen as water loss

Explanation: Syneresis is the expulsion of liquid from a hydrocolloid gel, so it appears as water loss and causes shrinkage.

• A. Agar-agar
• B. Alginate
• C. Zinc oxide eugenol
• D. Plaster of paris

Explanation: Agar-agar is preferred for duplicating casts because it is a reversible hydrocolloid that can reproduce fine detail and be liquefied for…

• A. Marcaptan group
• B. Silane group
• C. Hydroxyl group
• D. Virryl group

Explanation: The base paste of condensation silicone contains hydroxyl-terminated dimethyl siloxane, which reacts during condensation polymerisation.

• A. Moisture absorption
• B. All of the above
• C. Phenomenon of conversion of gel into sol
• D. Temperature lag between gelation and liquefaction temperature

Explanation: Hysteresis is the temperature difference between liquefaction and gelation of a hydrocolloid, allowing the sol-to-gel and gel-to-sol…

• A. They set by condensation polymerisation
• B. They exhibit a very low setting shrinkage
• C. They have a lower tear resistance than polysulphide rubbers
• D. They evolve hydrogen when cast if they are not fully cured

Explanation: Type II silicone is addition-cured silicone and sets by addition polymerisation, not condensation polymerisation.

• A. Cold
• B. Chemical reaction
• C. Heat
• D. Pressure

Explanation: Zinc oxide-eugenol impression paste hardens through a chemical chelation reaction that forms zinc eugenolate.

• A. Plaster of paris
• B. Anti - expansion solution
• C. Soluble plaster
• D. Die stones

Explanation: Potato starch is added to impression plaster to make it soluble, allowing the impression to be removed more easily from the cast.

• A. Inter metallic compounds
• B. Eutectic mixture
• C. Peritectic mixture
• D. Solid solution

Explanation: When components are completely miscible in the liquid state and remain uniformly mixed after solidification, they form a solid-solution…

• A. Grain
• B. Nucleus
• C. Stroma
• D. None of the above

Explanation: A grain is a single crystal region within a polycrystalline metal, with atoms arranged in a specific orientation.

• A. Inter atomic movement
• B. Arrangement of atoms
• C. Inter atomic imbalance
• D. Arrangement of molecules

Explanation: A space lattice is the regular three-dimensional arrangement of atoms in a crystalline solid.