Impression Material (Compound and Z.OE) MCQ PDF

**What is the purpose of impression materials in dentistry?** - A\) To create a positive replica of oral structures - B\) To register or reproduce the form and dimensions of teeth and oral tissues - C\) To serve as a filling material - D\) To create temporary crowns\ **Answer: B*...

**What is the purpose of impression materials in dentistry?** - A\) To create a positive replica of oral structures - B\) To register or reproduce the form and dimensions of teeth and oral tissues - C\) To serve as a filling material - D\) To create temporary crowns\ **Answer: B** **What is a primary impression?** - A\) A negative replica of hard and soft oral structures - B\) A first impression that does not record fine details - C\) A model for a single tooth - D\) A final impression that records all details\ **Answer: B** **What material is used to form a positive replica from an impression?** - A\) Die - B\) Stock tray - C\) Model materials - D\) Impression compound\ **Answer: C** **What is a stock tray primarily used for?** - A\) Making a secondary impression - B\) Carrying impression material into the mouth - C\) Creating special trays for individual patients - D\) Tracing borders for an acrylic tray\ **Answer: B** **Which of the following is NOT a desirable property of impression materials?** - A\) Toxicity - B\) Adequate flow - C\) Elasticity - D\) Dimensional stability\ **Answer: A** **Which impression material is classified as non-elastic?** - A\) Polysulfide - B\) Agar - C\) Zinc oxide eugenol - D\) Addition silicone\ **Answer: C** **What type of reaction is involved in setting reversible impression materials?** - A\) Physical reaction - B\) Chemical reaction - C\) Saponification - D\) Chelation\ **Answer: A** **What is the primary use of Type I (low-fusing) impression compound?** - A\) Taking secondary impressions for dentulous patients - B\) Taking primary impressions for completely edentulous patients - C\) Constructing orthodontic appliances - D\) Fabricating indirect restorations\ **Answer: B** **What acts as a plasticizer in impression compound composition?** - A\) Fillers - B\) Thermoplastic resin - C\) Stearic acid - D\) Colouring agents\ **Answer: C** **What is a disadvantage of impression compound?** - A\) Non-toxic - B\) Compatible with die materials - C\) Has adequate shelf life - D\) Dimensional changes on cooling\ **Answer: D** 11. **Which property of impression compound limits its ability to record fine details?** - A\) High fluidity - B\) High flow rate - C\) Inadequate flow rate - D\) Excellent thermal conductivity\ **Answer: C** 12. **How is Type II (tray compound) primarily used?** - A\) As a primary impression material for edentulous patients - B\) For taking final impressions in dentulous patients - C\) As a tray material - D\) For border tracing in acrylic trays\ **Answer: C** 13. **Which of the following is NOT a component of impression compound?** - A\) Thermoplastic resin - B\) Fillers - C\) Eugenol - D\) Coloring agents\ **Answer: C** 14. **What is a characteristic of zinc oxide eugenol impression material?** - A\) Elastic - B\) Used for secondary impressions in edentulous patients - C\) Has a high flow rate suitable for all patients - D\) Used for primary impressions in dentulous patients\ **Answer: B** 15. **What role does filler play in impression compound?** - A\) Increases fluidity - B\) Controls consistency and increases strength - C\) Provides color to the compound - D\) Acts as an irritant\ **Answer: B** 16. **What is the setting reaction type for zinc oxide eugenol?** - A\) Physical reversible reaction - B\) Chemical irreversible reaction - C\) Saponification - D\) Gelation\ **Answer: B** 17. **What should be applied to the patient's lips before taking a zinc oxide eugenol impression to prevent sticking?** - A\) Alcohol - B\) Petroleum jelly (Vaseline) - C\) Cold water - D\) Powder\ **Answer: B** 18. **How is impression compound softened before use?** - A\) Mixing with cold water - B\) Heating in a thermostatically controlled water bath - C\) Adding a catalyst - D\) Exposing to air\ **Answer: B** 19. **What happens to impression compound when it cools in the mouth?** - A\) It becomes more fluid - B\) It shrinks and hardens - C\) It retains its shape but softens - D\) It evaporates\ **Answer: B** 20. **Which material is used for taking border tracing in an acrylic tray?** - A\) Zinc oxide eugenol - B\) Type II impression compound - C\) Alginate - D\) Agar\ **Answer: B** 21. **The chemical reaction of zinc oxide eugenol involves which two processes?** - A\) Dehydration and precipitation - B\) Hydrolysis and chelation - C\) Gelation and saponification - D\) Polymerization and crystallization\ **Answer: B** 22. **How can the setting time of zinc oxide eugenol be accelerated?** - A\) Cooling the mixing pad - B\) Decreasing humidity - C\) Adding zinc acetate - D\) Increasing the base-to-catalyst ratio\ **Answer: C** 23. **What is the primary use of eugenol-free paste?** - A\) For dentulous patients - B\) For patients with eugenol allergy - C\) For tray construction - D\) As a border tracing material\ **Answer: B** 24. **What is a disadvantage of zinc oxide eugenol impression material?** - A\) High dimensional stability - B\) Compatible with cast materials - C\) Causes irritation in some patients - D\) Can be used with undercuts\ **Answer: C** 25. **Which substance in zinc oxide eugenol helps reduce its burning sensation?** - A\) Silica - B\) Oil of cloves - C\) Inert oils - D\) Kaolin\ **Answer: C** 26. **Which impression material type is NOT elastic?** - A\) Polyether - B\) Silicone - C\) Alginate - D\) Impression plaster\ **Answer: D** 27. **Which impression material is reversible and undergoes a physical setting reaction?** - A\) Zinc oxide eugenol - B\) Agar - C\) Polyether - D\) Polysulfide\ **Answer: B** 28. **What is the role of gum rosin in zinc oxide eugenol?** - A\) Provides color - B\) Acts as a plasticizer - C\) Increases strength - D\) Enhances setting time\ **Answer: B** 29. **Which material classification involves elastomers?** - A\) Non-elastic impression materials - B\) Elastic impression materials - C\) Physical reaction materials - D\) Thermoplastic materials\ **Answer: B** 30. **What is the effect of increasing the catalyst proportion in zinc oxide eugenol mixing?** - A\) Increases setting time - B\) Decreases setting time - C\) No effect on setting time - D\) Causes physical setting reaction\ **Answer: B** 31. **Which impression material has a high coefficient of thermal expansion?** - A\) Impression compound - B\) Polyether - C\) Alginate - D\) Zinc oxide eugenol\ **Answer: A** 32. **What color is the base paste of zinc oxide eugenol impression material?** - A\) Blue - B\) Red or brown - C\) White - D\) Green\ **Answer: C** 33. **What is a common setting time for Type II zinc oxide eugenol?** - A\) 5 minutes - B\) 10 minutes - C\) 15 minutes - D\) 20 minutes\ **Answer: C** 34. **What component in the impression compound helps increase hardness and stability?** - A\) Plasticizers - B\) Waxes - C\) Fillers - D\) Coloring agents\ **Answer: B** 35. **Why is it essential to pour an impression compound immediately after removal from the mouth?** - A\) To avoid thermal expansion - B\) To avoid shrinkage - C\) To retain elasticity - D\) To prevent discoloration\ **Answer: B** 36. **Which component in zinc oxide eugenol acts as a filler to increase strength?** - A\) Silica - B\) Zinc oxide - C\) Gum rosin - D\) Eugenol\ **Answer: A** 37. **Which type of impression material is typically used for primary impressions in edentulous patients?** - A\) Polyether - B\) Alginate - C\) Type I impression compound - D\) Addition silicone\ **Answer: C** 38. **What does "chelation" refer to in the setting reaction of zinc oxide eugenol?** - A\) A physical change - B\) A reversible reaction - C\) A bonding reaction between zinc oxide and eugenol - D\) A color change reaction\ **Answer: C** 39. **Which of the following can increase the setting time of zinc oxide eugenol?** - A\) Adding more catalyst - B\) Heating the spatula - C\) Adding wax to the mixing pad - D\) Mixing faster\ **Answer: C** 40. **What is the ideal setting time for Type I zinc oxide eugenol?** - A\) 5 minutes - B\) 7 minutes - C\) 10 minutes - D\) 12 minutes\ **Answer: C** 41. **What is a key feature of eugenol-free paste?** - A\) Contains ethoxy benzoic acid instead of eugenol - B\) Contains gum rosin instead of eugenol - C\) Has a physical setting reaction - D\) Sets at room temperature only\ **Answer: A** 42. **What is one way to prevent dimensional changes in impression compound?** - A\) Use at room temperature only - B\) Avoid immediate pouring after impression - C\) Gradual cooling in the mouth using water spray - D\) Let it air dry before pouring\ **Answer: C** 43. **Which impression material requires controlled temperature for softening?** - A\) Polyether - B\) Alginate - C\) Impression compound - D\) Zinc oxide eugenol\ **Answer: C** 44. **Which is NOT a type of tray material?** - A\) Impression compound - B\) Hydrocolloid - C\) Tray compound - D\) Alginate\ **Answer: D** 45. **What is the most common color for Type II zinc oxide eugenol catalyst paste?** - A\) White - B\) Blue - C\) Red or brown - D\) Green\ **Answer: C** 46. **Which impression material is known for poor thermal conductivity?** - A\) Agar - B\) Zinc oxide eugenol - C\) Alginate - D\) Impression compound\ **Answer: D** 47. **Why should vaseline be applied to lips before using zinc oxide eugenol?** - A\) To improve flow - B\) To prevent sticking - C\) To increase adhesion - D\) To cool the material\ **Answer: B** 48. **Which material has a reversible setting reaction?** - A\) Alginate - B\) Polyether - C\) Agar - D\) Zinc oxide eugenol\ **Answer: C** 49. **What is the role of a special tray?** - A\) To create primary impressions - B\) To carry material for secondary impressions - C\) To replicate all oral details in one step - D\) To act as a model tray\ **Answer: B** 50. **Which impression material cannot record undercuts?** - A\) Polyether - B\) Zinc oxide eugenol - C\) Addition silicone - D\) Agar\ **Answer: B** 51. **Which component controls the setting time in zinc oxide eugenol?** - A\) Wax - B\) Silica - C\) Filler amount - D\) Zinc acetate as an accelerator\ **Answer: D** 52. **Which setting reaction is irreversible?** - A\) Physical - B\) Reversible - C\) Chemical - D\) Thermal\ **Answer: C** 53. **What type of reaction does polyether undergo when setting?** - A\) Physical - B\) Chemical - C\) Thermal - D\) Expansion\ **Answer: B** 54. **Which impression material type requires a separating medium with the cast?** - A\) Polysulfide - B\) Zinc oxide eugenol - C\) Polyether - D\) Silicone\ **Answer: A** 55. **What kind of impression material is polyether?** - A\) Non-elastic - B\) Reversible hydrocolloid - C\) Elastic - D\) Thermoplastic\ **Answer: C** 56. **Which material is commonly used to form a primary model?** - A\) Alginate - B\) Zinc oxide eugenol - C\) Polyether - D\) Addition silicone\ **Answer: A** 57. **What type of tray is used to create customized impressions for individual patients?** - A\) Stock tray - B\) Special tray - C\) Perforated tray - D\) Rim-lock tray\ **Answer: B** 58. **Which material is softened by heat and hardens by cooling?** - A\) Agar - B\) Alginate - C\) Impression compound - D\) Polyether\ **Answer: C** 59. **Which impression material requires a water bath for softening?** - A\) Zinc oxide eugenol - B\) Type II impression compound - C\) Alginate - D\) Polyether\ **Answer: B** 60. **What component is added in impression compound for consistency and increased strength?** - A\) Thermoplastic resin - B\) Waxes - C\) Plasticizers - D\) Fillers\ **Answer: D** 61. **Which of these is an elastic impression material?** - A\) Zinc oxide eugenol - B\) Impression plaster - C\) Polysulfide - D\) Impression waxes\ **Answer: C** 62. **Why is zinc oxide eugenol ideal for edentulous patients?** - A\) It records undercuts - B\) It is highly fluid - C\) It has low dimensional stability - D\) It provides accurate detail for tissues without undercuts\ **Answer: D** 63. **What is the function of plasticizers in impression compounds?** - A\) Control hardness - B\) Act as lubricants to control consistency - C\) Act as a retarder - D\) Provide strength\ **Answer: B** 64. **Which impression material is known for its chemical setting through a process called "saponification"?** - A\) Polyether - B\) Agar - C\) Eugenol-free zinc oxide - D\) Alginate\ **Answer: C** 65. **Which of these compounds acts as an accelerator in zinc oxide eugenol?** - A\) Calcium chloride - B\) Talc - C\) Inert oil - D\) Coloring agent\ **Answer: A** 66. **What type of material is used for border molding in denture fabrication?** - A\) Alginate - B\) Zinc oxide eugenol - C\) Tray compound - D\) Addition silicone\ **Answer: C** 67. **Which is a characteristic feature of Type II impression compound?** - A\) Low fusing - B\) Used as tray material - C\) Irreversible reaction - D\) Primarily for secondary impressions\ **Answer: B** 68. **What happens when zinc oxide eugenol is exposed to moisture?** - A\) Sets slower - B\) Sets faster - C\) Reduces dimensional stability - D\) Becomes flexible\ **Answer: B** 69. **Which material is primarily used to study tooth alignment and treatment planning?** - A\) Impression compound - B\) Alginate - C\) Zinc oxide eugenol - D\) Polyether\ **Answer: B** 70. **Why is it important to mix zinc oxide eugenol thoroughly?** - A\) To increase strength - B\) To ensure homogeneous color - C\) To prevent shrinkage - D\) To increase viscosity\ **Answer: B** 71. **What type of reaction occurs in agar when it sets?** - A\) Chemical irreversible reaction - B\) Physical reversible reaction - C\) Saponification - D\) Gelation\ **Answer: B** 72. **Which impression material is commonly used in two layers for better detail?** - A\) Alginate - B\) Impression plaster - C\) Putty wash - D\) Tray compound\ **Answer: C** 73. **Which component in impression compound provides color?** - A\) Thermoplastic resin - B\) Filler - C\) Coloring agents like rouge - D\) Plasticizer\ **Answer: C** 74. **What is the primary purpose of using a stock tray with primary impression material?** - A\) To carry the impression material into the patient\'s mouth - B\) To capture fine detail - C\) To record undercuts - D\) To store the impression\ **Answer: A** 75. **What is the shelf life of an ideal impression material?** - A\) Very short - B\) Should be adequate for storage needs - C\) Infinite - D\) Dependent on exposure to light\ **Answer: B** 76. **Which material is NOT compatible with undercuts?** - A\) Polyether - B\) Agar - C\) Zinc oxide eugenol - D\) Silicone elastomer\ **Answer: C** 77. **What is a key benefit of using zinc oxide eugenol for edentulous patients?** - A\) High elasticity - B\) High dimensional stability - C\) Fast setting time - D\) Low viscosity\ **Answer: B** 78. **Which factor does NOT accelerate the setting of zinc oxide eugenol?** - A\) Heat - B\) Humidity - C\) Increased mixing time - D\) Reducing base ratio\ **Answer: D** 79. **What is one disadvantage of alginate as an impression material?** - A\) Elasticity - B\) Good detail reproduction - C\) Poor dimensional stability over time - D\) Easy to handle\ **Answer: C** 80. **Which type of impression material is ideal for recording fine details and is irreversible?** - A\) Alginate - B\) Impression plaster - C\) Tray compound - D\) Zinc oxide eugenol\ **Answer: A** 81. **Which material is typically used to make a final impression for a patient with shallow undercuts?** - A\) Polyether - B\) Zinc oxide eugenol - C\) Type II impression compound - D\) Alginate\ **Answer: B** 82. **What does a high coefficient of thermal expansion mean for impression materials?** - A\) They expand slightly in cold temperatures - B\) They undergo shrinkage upon cooling - C\) They are resistant to heat - D\) They become more fluid with heat\ **Answer: B** 83. **Which impression material must be mixed using a flexible stainless steel spatula?** - A\) Alginate - B\) Agar - C\) Zinc oxide eugenol - D\) Polyether\ **Answer: C** 84. **Why is it necessary to disinfect impressions made from zinc oxide eugenol?** - A\) Prevents setting delays - B\) Reduces dimensional changes - C\) Prevents infection transmission - D\) Increases strength of the impression\ **Answer: C** 85. **What is a benefit of eugenol-free paste for patients?** - A\) Reduces odor - B\) Avoids potential burning sensation - C\) Increases setting time - D\) Decreases cost\ **Answer: B** 86. **Which impression material requires a water spray for controlled cooling in the mouth?** - A\) Alginate - B\) Zinc oxide eugenol - C\) Impression compound - D\) Polyether\ **Answer: C** 87. **What is the main function of calcium chloride in zinc oxide eugenol?** - A\) Reduces burning - B\) Acts as a filler - C\) Acts as an accelerator - D\) Provides color\ **Answer: C** 88. **Why is an acrylic special tray used for secondary impressions?** - A\) To ensure a customized fit for the patient\'s mouth - B\) To increase material flexibility - C\) To absorb moisture - D\) To store impression materials\ **Answer: A** 89. **What happens if the proportion of catalyst is increased in zinc oxide eugenol?** - A\) Setting time is increased - B\) Setting time is decreased - C\) Dimensional stability is reduced - D\) It remains unaffected\ **Answer: B** 90. **Which material has a chemical reaction that is less affected by temperature and humidity?** - A\) Alginate - B\) Eugenol-free zinc oxide - C\) Polyether - D\) Agar\ **Answer: B** 91. **What is the common use of alginate in dentistry?** - A\) Final impressions for complete dentures - B\) Primary impressions for study models - C\) Border tracing - D\) Fabricating crowns\ **Answer: B** 92. **What property allows impression compound to be reused?** - A\) High elasticity - B\) Thermoplastic behavior - C\) Chemical setting reaction - D\) Low thermal conductivity\ **Answer: B** 93. **Which substance is added to prevent irritation in zinc oxide eugenol impressions?** - A\) Silica - B\) Kaolin - C\) Inert oils - D\) Calcium chloride\ **Answer: C** 94. **What is a major disadvantage of using impression compound for fine detail reproduction?** - A\) High fluidity - B\) Inadequate flow - C\) Low dimensional stability - D\) Requires heating before use\ **Answer: B** 95. **What setting time adjustment factor should be avoided to prevent excessive quick setting of zinc oxide eugenol?** - A\) Increasing catalyst - B\) Adding fillers - C\) Heating mixing instruments - D\) Using excess water\ **Answer: D** 96. **Which component provides the thermoplastic property in impression compounds?** - A\) Thermoplastic resin and waxes - B\) Fillers - C\) Coloring agents - D\) Inert oils\ **Answer: A** 97. **What makes polyether different from other impression materials?** - A\) Reversible reaction - B\) Chemical setting with high dimensional accuracy - C\) Elasticity with poor dimensional stability - D\) Non-elastic property\ **Answer: B** 98. **How is the border of an acrylic tray typically traced?** - A\) Using a water bath - B\) Applying tray compound - C\) Softening impression plaster - D\) Using polyether material\ **Answer: B** 99. **What color is often used for eugenol-free zinc oxide catalyst paste?** - A\) White - B\) Red - C\) Blue - D\) Green\ **Answer: C** 100. **Which impression material is primarily used for making casts and study models due to its low cost?** - A) Zinc oxide eugenol - B) Alginate - C) Polyether - D) Impression compound\ **Answer: B**