Cements

Question 0

What are the properties of a GIC cement? (e.g. KetacCem, Fuji I)

Answer 0

1) Working time of about 3 minutes
2) Water loss and absorption can lead to cracks if left to dessicate for more than 10 minutes
3) Chemical bonding to tooth
4) High compressive strength but low mmodulus of elasticity
5) Fluoride release
Patients should limit functional stress for several days after cementation

Question 1

What are the ideal properties for a cement?

Answer 1

1) Biocompatible
2) Sufficient working time
3) Low film thickness
4) Low solubility
5) High compressive and tensile strength
6) Adheres to tooth structure and restorative material

Question 2

What are some properties of RMGIC cements? (e.g. Fuji Plus, Fuji Cem)

Answer 2

1) Less moisture sensitive
2) Susceptibile to dehydration shrinkage
3) Voolummetric expansion over time (also due to hydrophillic nature of resin and long term water sorption) means unsuitable for veneers and ceramic crowns and posts.
4) Film thickness and adhesion siimilarr to GIC.

Question 3

How can resin cements be classified according to bonding procedure?

Answer 3

1) Total etch (Nexus III)
2) One step etch and bond (Panavia F 2.0)
3) Self adhesive resin (RelyX Unicem)

Question 4

What are the advantages of using resin cement?

Answer 4

1) Good compressive and tensile strength
2) Low sollubility
3) Good aesthetics
4) Micromechanical bonding to tooth and chemical bonding to etched and silanated porcelein

Question 5

What are the disadvantages of using a resin cement?

Answer 5

1) Difficultt to remove
2) Post-op sensitivity
3) Technique sensitive
4) Eugenol inhibition of plymerisation