Glass Ionomer Lining Materials Flashcards
Describe the working and setting time of glass ionomer
Light cured and so are command set
This gives a long working time and a short setting time (30s)
Compare the thermal conductivity and diffusivity of glass ionomer to dentine
Lower than dentine for both GIC and RMGIC
Compare the thermal expansion of glass ionomer to dentine
Similar to dentine
Compare the compressive strength of glass ionomer to dentine and other lining materials
Compressive strength is >170MPa which is lower than dentine but higher than any of the ZnO based materials
Why does glass ionomer have a good marginal seal
There is a chemical bond to dentine and enamel
They seal dentinal tubules which decreases microleakage and helps prevent post treatment sensitivity
Compare the solubility of glass ionomer to other lining materials
Solubility is greater for conventional GIC than RMGIC
GIC materials are less soluble than any other liners apart from zinc phosphate cement
RMGIC is less soluble than any other cement
What happens during the polymerisation reaction RMGICs
Benzoyl iodides and benzoyl bromides are released which are cytotoxic and can be effective against residual cavity bacteria
Why must RMGICs always be completely cured
Any unreacted HEMA may damage the pulp
Why are GIC materials cariostatic
Fluoride is released
Why are GIC materials used often as linings for composite resin
GICs are the only lining able to bond to composite resin
What lining materials should be used in the dental hospital
RMGIC such as vitrebond for amalgam and larger cavities to be filled with composite
Calcium hydroxide should be used when the cavity approaches the pulp - acts as a direct or indirect pulp cap
What should you do after placing calcium hydroxide
Cover it with RMGIC prior to a final restoration being placed
This protects the calcium hydroxide and prevents dissolution beneath the restoration
