Comparison of Restorative Materials Flashcards
Resin composites can be chemically cured, what does this mean for the dispensary method?
Two paste system
What are some of the disadvantages of two paste resin composites? (5)
What do these disadvantages ultimately effect?
- Mixing is difficult
- Incorporation of air bubbles
- Discolouration with time
- Homogeneous mix is not easy to get
- Degree and time of polymerisation varies throughout the mass
- Effect modulus and strength
What are some advantages of using light cured resins over two pastes? (4)
- Minimal porosity
- Less discolouration
- Virtually command set
- Rapid polymerisation
What are some disadvantages of light cured resins? (5)
- Light sensitive during application
- Thin inhibited layer
- Limited depth of cure
- Cure in increments
- Retina damage from curing light
Why do we use amalgamators instead of manual mixing for amalgams? (2)
- Better mix using amalgamators
- Mercury vapour exposure when manually mixing
Name some advantages of phenolate bonded acid-base cements (3)
- Easy to mix
- Long working time
- Quick set in the mouth
Name the 2 phenolate bonded acid base cements
- Zinc oxide eugenol (ZOE)
- Calcium hydroxide
Name the 2 polycarboxylate bonded acid base cements
- Zinc polycarboxylate cements
- Glass ionomer cements
How would you mix zinc phosphate cements? (3)
- Cooled slab
- Small increments
- Over large area
With a zinc phosphate cement how would decreased powder:liquid affect;
- Compressive strength
- Solubility
- Initial acidity
- Setting time
- Decrease
- Increase
- Increase
- Increase
With a zinc phosphate cement how would increased rate of powder incorporation affect;
- Compressive strength
- Solubility
- Initial acidity
- Setting time
- Decrease
- Increase
- Increase
- Decrease
With a zinc phosphate cement how would increased mixing time affect;
- Compressive strength
- Solubility
- Initial acidity
- Setting time
- Decrease
- Increase
- Increase
- Decrease
With a zinc phosphate cement how would water contamination affect;
- Compressive strength
- Solubility
- Initial acidity
- Setting time
- Decrease
- Increase
- Increase
- Decrease or Increase
List the pH values for the following cements;
- Phosphoric acid solution
- Poly(acrylic acid) solution
- Zinc phosphate cement
- Glass ionomer cement
- Zinc polycarboxylate cement
- ZOE cement
- Calcium hydroxide cement
- 1.5
- 2.5
- 3.0
- 3.5
- 4.0
- 5.0
- 9.0
What happens to the pH of acid-base cements over time? Why?
Increases over time as acid becomes neutralised
Which cement causes severe pulpal irritation?
Zinc phosphate
Which cements cause the least amount of pulpal irritation? (2)
Why do these cements not cause pulpal irritation?
- ZOE cement
- Calcium hydroxide cement
- As not acidic
Which restorative material is the least soluble?
Composites
Which restorative material is the most soluble?
Calcium hydroxide cement
Which restorative material has conductivity properties similar to that of dentine?
ZOE cement
Which restorative material has diffusivity properties similar to that of dentine?
GIC
Which restorative material has the best conductivity and diffusivity properties?
Amalgam
Which restorative material has expansion properties similar to that of a tooth?
GIC
What is the compressive strength of;
Enamel?
Dentine?
- Enamel = 350 MPa
- Dentine = 270 MPa
