Impressions for Removable Partial Dentures Short Question And Answers

Impressions for Removable Partial Dentures Short Question And Answers

Impressions

Multiple Choice Questions

Question 1. The dimensional stability of an impression material depends on all the following factors except _______________ .

1. A by-product of setting reaction.
2. Mixing technique.
3. Storage condition.
4. Continuity of setting reaction.
5. Time length of storage.

Answer. 2. Mixing technique.

Read And Learn More: Fixed Partial Denture Short Essay Question And Answers

Question 2. If you leave a condensation-cured silicone impression material at room temperature for 2 days without any coverage, what kind of error will occur?

1. Only the stone model becomes bigger.
2. Only the restoration becomes bigger.
3. The stone model and the restoration may become bigger and more distorted.
4. No changes will happen.
5. The stone model becomes smaller, but the restoration becomes bigger.

Answer. 3. The stone model and the restoration may become bigger and distorted.

Question 3. Which one of the following impression materials can record only the much compressive form of the tissue?

1. Zinc oxide eugenol.
2. Impression plaster.
3. Light body silicone impression materials.
4. Impression compound.
5. Alginate.

Answer. 4. Impression compound.

Question 4. Which one of the following impression materials should not be used with latex gloves and rubber dams?

1. Addition-cured silicone.
2. Polysulphide.
3. Polyether.
4. Condensation-cured silicone.
5. Zinc oxide eugenol.

Answer. 1. Addition-cured silicone.

Question 5. Which one of the following physical properties can be expected in an impression material without any setting by-products?

1. A higher degree of detail is recorded.
2. Better handling characteristics.
3. Hydrophobic behavior.
4. Better dimensional stability.
5. Better taste and odor.

Answer. 4. Better dimensional stability.

Question 6. Which one of the following impression materials is not suitable as a final impression material for tooth preparations?

1. Polyether.
2. Addition-cure silicone.
3. Condensation-cure silicone.
4. Polysulphide.
5. Alginate.

Answer. 5. Alginate

Question 7. Which is the preferred order (from left to right) for disinfecting an impression?

1. Rinse, spray with disinfectant, pack, and send it to the lab.
2. Rinse, immerse in disinfectant, pack, and send it to the lab.
3. Rinse, immerse in disinfectant, rinse, pack, and send it to the lab.
4. Spray with disinfectant, rinse, pack, and send it to the lab.
5. Immerse in disinfectant, rinse, pack, and send it to the lab.

Answer. 3. Rinse, immerse in disinfectant, rinse, pack, and send it to the lab.

Question 8. What is the setting time of the polysulfide rubber base?

1. 12–14 min.
2. 5 min.
3. 7–8 min.
4. 10 min.
5. 20 min.

Answer. 1. 12-14 min.

Question 9. Choose the material that has poor finish line readability.

1. Polysulfide rubber base.
2. Polyether rubber base.
3. Polyvinyl siloxane.
4. Reversible hydrocolloid.
5. Polymethyl siloxane.

Answer. 4. Reversible hydrocolloid

Question 10. Which is the radiopaque material?

1. Polysulfide rubber base.
2. Polyether rubber base.
3. Polyvinyl siloxane.
4. Reversible hydrocolloid.
5. Polymethyl siloxane.

Answer. 1. Polysulfide rubber base.

Question 11. Which one of the following materials has the poorest moisture tolerance?

1. Polysulfide rubber base.
2. Polyether rubber base.
3. Polyvinyl siloxane.
4. Reversible hydrocolloid.
5. Impression compound.

Answer. 3. Polyvinyl siloxane.

Question 12. Choose the material that has poor odor/taste.

1. Polyether rubber base.
2. Polyvinyl siloxane.
3. Reversible hydrocolloid.
4. Polymethyl siloxane.
5. Polysulfide rubber base.

Answer. 1. Polyether rubber base.

Question 13. To achieve maximum adhesion of the impression material to the tray, allow the tray adhesive to dry for a minimum of ________________.

1. 15 minutes.
2. 15 seconds.
3. 15 hours.
4. 10 minutes.
5. 10 seconds.

Answer. 1. 15 minutes.

Question 14. Arrange these impression materials in their hydrophobic ascending order.

1. Polysulfide, polyvinyl siloxanes and condensation reaction silicones.
2. Polyvinyl siloxanes, polysulfide and condensation reaction silicones.
3. Polysulfide, condensation reaction silicones and polyvinyl siloxanes.

Answer. 1. Polysulfide, polyvinyl siloxanes, and condensation reaction silicones.

Extended Matching Questions

Question 1. Theme: Impression Materials

A. Polysulfide.

B. Condensation-cured silicon.

C. Addition-cured silicon.

D. Polyether.

E. Compound.

F. Alginate.

G. Agar.

Using a letter from A to G, choose the most appropriate impression material from the list above that best matches each of the following descriptions numbered 1–5 below. You may use each response A–G, once only or not at all.

A radiopaque elastomeric impression material with the highest viscoelastic behavior.

The impression material of choice when there is poor moisture control.

The impression material with the highest dimensional stability.

A thermoplastic impression material.

An impression using a material that can be kept only for 2 hours in a humid environment before preparing the model.

Short Answer Questions

Question 1. 1. List four varieties of addition-cure silicone impression materials based on their consistency.

Light body, medium body, heavy body, and putty.

Question 2. Which one of the above-mentioned types has the highest filler content? What are its advantages and disadvantages compared to others? (One point each)

• Putty.
• Low polymerization shrinkage, low coefficient of thermal expansion.
• Less detailed record, less accuracy.

Question 2. What is the function of these modifiers in agar composition?

• Sodium tetraborate increases the strength of the gel and viscosity of the gel
• Borax retarder
• Potassium sulfate counteracts borax; increases rupture strength, and improves plastic deformation
• Thymol – Bactericidal.

Question 3. 1. You are about to make a final impression and send it to a dental lab to produce a cast partial denture. The impression is expected to reach the lab after three days. There are relatively deep hard and soft tissue undercuts. Which impression material will you use? Why?

• Addition-silicon impression material.
• Good dimensional stability.

Question 2. What kind of error may occur when the impression is debonded from the tray? How this can be prevented?

The impression will be distorted.
It can be prevented by using a perforated tray or using tray adhesive.

Question 3. Explain one technique to minimize the distortion of an impression when removing it from the patient’s mouth.

Fast removal (sharp tug) of the impression from the mouth.

Fill in the blanks

Question 1. Impression materials can be classified as readily wettable by gypsum ___________ and resistant to wetting ___________.

Answer. hydrophilic, hydrophobic

Question 2. The use of a ___________ is effective in reducing both the contact angle and the number of voids trapped in the resulting cast.

Answer. surfactant on impression surface

Question 3. A material that exhibits this property of becoming more fluid when the shear rate is increased by deforming or “disturbing” it (shaking, spatulating, or injecting through a syringe) is described as ___________.

Answer. thixotropic

Question 4. The mechanisms by which the hydrocolloids can lose water by ___________ or by ___________.

Answer. syneresis [water seeping from the surface], evaporation

Question 5. The mechanism by which the hydrocolloids can absorb water ___________.

Answer. imbibition

Question 6. The dimensions for the tissue stops in a customized tray is ___________.

Answer. 3 x 3 mm

Working cast and dies

Multiple Choice Questions

Question 1. The disadvantage of using a working cast with a separated die is:

1. Poor finishing line.
2. Distortion of the wax pattern.
3. Overextension of the finishing line.
4. Poor esthetics.
5. Weak restoration.

Answer. 2. Distortion of the wax pattern.

Question 2. The Pindex machine in Pindex system of preparing working cast and die is used for:

1. Locating and paralleling the pin holes.
2. Inserting the pins in the pin holes.
3. Gluing the pins in the pin holes.
4. Ditching (trimming) below the finishing line.
5. Splitting the die.

Answer. 1. Locating and paralleling the pin holes.

Question 3. The thickness of the relief agent for coating over a die is:

1. 20–40 mm.
2. 60–80 mm.
3. 0–10 cm.
4. 20–40 µm.
5. 60–80 µm.

Answer. 4. 20–40 µm.

Question 4. When a working cast with a removable die is used to prepare a wax pattern, the risk of one of the following errors is highest:

1. Distortion of the wax pattern.
2. Discrepancy between the die and working cast.
3. Discrepancy in the thickness of the die spacer and working cast.
4. Improper reseating of the die on the working cast.
5. Overextension of the finishing line.

Answer. 4. Improper reseating of the die on the working cast.

Question 5. During the die preparation, the finish line should not be highlighted with a sharp colorbrite _____________________ pencil.

1. Red.
2. Black.
3. Blue.
4. Green.

Answer. 2. Black.

Question 6. When a cut was made on the mesial and distal side of each die, the cuts should taper towards each other slightly from:

1. Occlusal to gingival.
2. Mesial to distal.
3. Gingival to occlusal.
4. Distal to mesial.

Answer. 1. Occlusal to gingival.

Question 7. What is the recommended thickness of the working cast to have an adequate handle on the die?

1. 1 inch.
2. 1 feet.
3. 1 centimeter.

Answer. 1. 1 inch.

Short Answer Questions

Question 1. Explain the basic difference between working cast with a separated die and with a removable die.

Working cast with separated die: Preparing a segmental cast (die) and a full arch cast separately in a two-pour technique.

Working cast with removable die: Preparing a full arch cast in a single pour and separating each individual abutment tooth (die) on that cast.

Question 2. Why working die be trimmed under the finishing line?

To gain access for carving the wax on the finishing line.

Question 3. List different techniques of working cast with a removable die (two techniques).

1. Straight dowel pin
2. Curved dowel pin
3. Pindex system
4. Di-lok tray.

Cementation

Multiple Choice Questions

Question 1. The internal configuration in an extra coronal restoration allows:

1. The restoration to the seat completely without binding.
2. Intimate contact of the restoration with the distal wall of the tooth.
3. Intimate contact of the restoration with the occlusal surface of the tooth.
4. An internal surface that is conducive to a weaker cement bond.
5. Intimate contact of the restoration with the mesial wall of the tooth.

Answer. 1. The restoration to the seat completely without binding.

Question 2. The microcrystalline surface layer formed by the abraded surface material, filling into the surface irregularities is known as:

1. Beilby layer.
2. Abraded layer.
3. Filled layer.
4. Surface layer.
5. Lailby layer.

Answer. 1. Beilby layer.

Question 3. In terms of bond strength, which one of the following luting cement should be the material of choice to cement an all-ceramic crown?

1. Zinc polycarboxylate cement.
2. Glass ionomer cement.
3. Zinc phosphate cement.
4. Zinc oxide eugenol cement.
5. Resin cement.

Answer. 5. Resin cement.

Question 4. Which step you will not evaluate before you cement a fixed restoration in the patient’s mouth?

1. Proximal contacts.
2. Internal fit.
3. Margins.
4. Stability.
5. Taper.

Answer. 5. Taper.

Question 5. Which one is not called a defective margin in a fixed restoration?

1. Overextended margins.
2. Underextended margins.
3. Thick margins.
4. Open margins.
5. Closed margins.

Answer. 5. Closed margins

Question 6. What is the obtainable or acceptable marginal gap in the fixed restorations?

1. 30–50 µm.
2. 50–60 µm.
3. 60–70 µm.
4. 70–80 µm.
5. 80–90 µm.

Answer. 1. 30-50 µm.

Question 7. The best instrument used to detect the marginal gap of a metal crown clinically is:

1. William’s periodontal probe.
2. Sharp straight explorer.
3. CPITN probe.
4. Gingival marginal trimmer.
5. Wax carver.

Answer. 2. Sharp straight explorer

Question 8. The long-term success of any cemented fixed restoration is not influenced by:

1. Dispensing of appropriate cleaning aids.
2. Length and width ratio of the preparation.
3. Type of the restorative material.
4. Type of the luting cement.

Answer. 1. Dispensing of appropriate cleaning aids.

Short Answer Questions

Question 1. List any five factors that are essential for the long-term success of the cemented fixed restoration.

• Dispensing of appropriate cleaning aids
• Home care instructions
• Quality of patient’s oral hygiene
• Removal of the excess cement
• Pulpal and periodontal status of the tooth
• Taper of the preparation
• Length and width ratio of the preparation
• Type of the restorative material
• Type of the luting cement.

Question 2. You have prepared a mandibular molar FDI 36 to receive a full gold crown restoration.

Question 1. List down six things that you want to evaluate before you cement it in the patient’s mouth.

• Proximal contacts
• Internal fit
• Margins
• Stability
• Occlusion
• Contours
• Esthetics.

Question 2. On examination, you have found there is a defective margin List the four different types of defective margins in a fixed restoration.

• Overextended margins
• Underextended margins
• Thick margins
• Open margins.

Question 3. You are evaluating a full gold crown received from the laboratory prior to permanently cementing this on a mandibular molar tooth FDI 46.

Which instrument will you use to detect the marginal gap clinically

Sharp explorer.

List four different types of defective margins in a fixed restoration

• Overextended margins
• Underextended margins
• Thick margins
• Open margins.

List two causes for a poorly adapted crown margin.

• Too tight proximal contact prevents the complete seating of the restoration
• Distortion of the restoration
• Internal discrepancies or nodules on the inner side of the restoration.

Question 4. A patient who had his vital tooth FDI 21 prepared for a metal-ceramic crown a week ago attended for cementation of the final crown. The patient reports symptoms in the prepared tooth.

Question 1. What symptoms may force you to delay the permanent cementation?

The patient complained of hypersensitivity/pain following the provisional restoration.

Question 2. What are the possible causes for the patient to become symptomatic?

• Hyperocclusion of provisional restoration
• Deficiency in the provisional restoration
• Pulmonary exposure/trauma during preparation.

Question 3. What clinical investigations would you carry out in sequence for the patient during this appointment?

• Sensibility test, percussion test, and TTP (tooth tender to percussion), if positive
• Periapical radiograph.

Question 4. How will you manage the tooth further if your attempts at non-invasive management are going to fail?

If the non-invasive management fails then the tooth is indicated for root canal treatment

Question 5. List the five preparatory procedures that need to be performed on any type of cemented restoration after it is fabricated from the laboratory.

• Preliminary finishing
• Try-in and adjustment
• Presentation and polishing
• Cementation
• Postcementation finishing.

Question 6. List the four advantages of having a correct internal configuration in a fixed restoration.

• To sit completely without binding
• Provides space for the luting cement
• Allows the margins to lie in intimate contact with the finish line
• Provides an internal surface that is conducive to a strong cement bond.

Question 7. What are the consequences of not having proper proximal contacts before you cement a fixed restoration in the patient’s mouth?

• If it is too tight – interferes with the correct seating of the restoration
  • Produce discomfort to the patient
  • Difficulty to floss
  • Fracture of ceramic in an all-ceramic or metal-ceramic restoration.
• If it is too light
  • Impaction of strands of food which is deleterious to gingiva.

Question 8. Can you explain the steps in doing the occlusal adjustments in a fixed restoration before you cement the crown?

• Compare the occlusal contact in the adjacent tooth before and after placement of the crown with the help of shim stock, if there is a variation correct the crown occlusal surface with the help of articulating papers till the patient can hold the shim stock on the adjacent tooth same way before and after crown placement.
• Then check if the patient can hold the shim stock also with the crown the same way as the adjacent tooth to make sure there is no overreduction in the occlusal surface of the crown.
• Once the centric relation is corrected use two different colors to correct the deflective contacts in the eccentric relation.

Pontics

Multiple Choice Questions

Question 1. The preferred material of choice on the tissue surface of a pontic is:

1. Polished metal.
2. Polished porcelain.
3. Resin bonded to metal.
4. Polished self-cure resin.
5. Polished heat-cure resin.

Answer. Polished porcelain.

Question 2. The saddle pontic is also called as:

1. Ridge lap.
2. Hygienic.
3. Conical.
4. Ovate.
5. Prefabricated pontic.

Answer. 1. Ridge lap.

Question 3. The Perel pontic is also called as:

1. Ridge lap.
2. Hygienic.
3. Conical.
4. Ovate.
5. Prefabricated pontic.

Answer. 2. Hygienic.

Question 4. The occlusogingival thickness of the hygienic pontic should not be less than:

1. 3.0 mm.
2. 3.0 cm.
3. 3.0 inch.
4. 3.0 m.
5. 3.0 µm.

Answer. 1. 3.0 mm.

Question 5. The preferred pontic design over thin ridges in the non-esthetic zone is:

1. Ridge lap.
2. Hygienic.
3. Conical.
4. Ovate.
5. Prefabricated pontic.

Answer. 3. Conical.

Question 6. The preferred pontic design in the mandibular posterior region is:

1. Ridge lap pontic.
2. Hygienic pontic.
3. Conical pontic.
4. Ovate pontic.
5. Prefabricated pontic.

Answer. 2. Hygienic pontic.

Question 7. What type of pontic design would you use in a patient with a high esthetic demand for a fixed partial denture?

1. The ridge lap pontic.
2. The sanitary pontic.
3. The modified ridge lap pontic.
4. An ovate pontic.
5. Bullet-shaped pontic.

Answer. 3. The modified ridge lap pontic.

Question 8. Which one of the following pontic designs is indicated when replacing a missing upper central incisor for a patient with a high smile line?

1. Ridge lap.
2. Sanitary.
3. Saddle.
4. Ovate.
5. Bullet shaped.

Answer. 4. Ovate.

Question 9. The treatment of choice to correct a reduced pontic space due to tilting of abutment teeth is:

1. Repositioning the teeth orthodontically.
2. Modifying abutment teeth with full coverage retainers.
3. Modifying abutment retainers to eliminate the need for a pontic.
4. Accommodating the pontic in the available space.
5. Increasing the thickness of connectors.

Answer. 1. Repositioning the teeth orthodontically.

Extended Matching Questions

Question 1. Theme: Pontics

A. Saddle pontic.

B. Modified ridge lap pontic.

C. Hygienic pontic.

D. Conical pontic.

E. Ovate pontic.

F. Metal ceramic pontic.

G. Prefabricated pontic facing.

Using a letter from A to G, choose the most appropriate pontic design from the list above that best matches each of the following descriptions numbered 1–5 below. You may use each option once only or not at all.

1. Preferred over thin ridges of the nonesthetic zone.
2. Forms a large concave contact with the ridge.
3. Used only in the nonesthetics zone.
4. Used where esthetics is a primary concern.
5. Has tissue contact which does not extend lingually.

Short note Questions

Draw and explain the different types of ridge deformities given by Siebert

Answer

• 1 – Faciolingual loss of tissue width with normal ridge heigh
• 2 – loss of ridge height with normal ridge width
• 3 – combinations of loss in both dimensions
• 4 – minimal deformity.

Regarding pontic contact with the tissues, which picture is wrong and why?

B – Wrong

Reason – Food entrapment

Fill in the blanks

Question 1. The occlusal forces exerted against the prosthetic appliances has been shown to be ______ lb for removable partial dentures: ______ lb for fixed partial dentures: ______ lb for natural teeth.

Answer. 26, 54.5, 150