Resins

Question 1

Classification

Answer 1

• Based upon its origin
• Based on Thermal Behavior
• Based on structural units

Question 2

Impression techniques

Answer 2

• Putty wash or reline technique
  
  • single mix
  • multiple mix
• Triple tray or double arch technique
• Triple tray or double arch technique

Question 3

Ideal requirements

Answer 3

• translucent to be esthetic
• color stability especially to withstand changes due to temp and dilute acids
• dimensionally stable
• adequate strength
• reduced water sorption
• insol to oral in oral fluids
• tasteless, odorless, non toxic, non-irritating

Question 4

classification of denture base materials

Answer 4

• based on duration of use
• based on materials used
• based on chemical composition of resins
• based on duration of use (temporary/permanent)
• based on material used (nonmetallic/metallic)
• based on Chemical composition of resin (acrylic, dimethacrylate, composites

Question 5

types of acrylic resin

Answer 5

-based on their mode of activation(heat, chemically, light)
-based on filler particles(unfilled-acrylic, filled-composites)
-

Question 6

stages of polymerization

Answer 6

1. wet sandy stage
2. early stringy stage
3. late stringy stage
4. Dough or gel stage
5. rubbery stage
6. stiff stage

Question 7

processing of Denture base(compression molding technique)

Answer 7

1. preparation of wax pattern
2. Investing
3. wax elimination
4. preparation of mold space
5. packing of resin
6. trial closure
7. Curing: processing of denture base
8. Bench cooling
9. deflasking
10. trimming/polishing

Question 8

• formation of surface cracks on denture base resin
• foggy appearance
• microscoping or macroscopic
• caused by mechanical stress during processing

Answer 8

surface crazing

Question 9

• surface irregularity present on surface of denture
• alters esthetics
• difficult to maintain by patient
• weakens with greater tendency for fracture

Answer 9

porosity

Question 10

• occurs in voids of bubbles
• not present on surface of denture
• confined to thick portion of denture base, not uniform

cause: vaporization of monomer when reaching 100.8 deg
prevent: those w/ excessive thickness should be cured using long low temp

Answer 10

internal porosity

Question 11

• can occur anywhere in denture surface
• resin may appear pale

cause: improper mixing
prevent: proper ratio, proper kneading of dough before packing

Answer 11

external porosity

Question 12

• during packing, the amount of resin does not completely fill mold space
  prevent: trial closure

Answer 12

inadequate pressure

Question 13

crazed dentures which have surface cracks will fractures after a certain time

Answer 13

fatigue failure

Question 14

denture cleansers

Answer 14

1. soap and water
2. alkaline peroxides
3. sodium hypochlorite soln
4. dilute acids
5. denture abrasive paste