Glass Ionomer Flashcards
What type of GIC do we have?
RMGIC
GIC
What is glass ionomer composed of?
POWDER (BASE)
LIQUID (ACID)
What is the powder composed of?
Silica
Aluminia
Calcium fluoride
Aluminum fluoride
What is the liquid composed of?
Polyacrylic acid
tartaric acid (increases setting time)
What is the setting rxn for GIC?
It is an acid base reaction that occurs in three stages:
DISSOLUTION
GELATION
HARDENING
Describe the setting of GIC
Dissolution - this is where the acid goes into solution when mixed and reacts with the outer layers of the gland
Gelation = this is where calcium ions form crosslinks and results in initial set of GIC (takes several minutes) and is due to formation of calcium polyacrylate
Hardening = this is final set of GIC that can take up to 7 days and it is where trivalent aluminium ions crosslink to increase strength
What can make GIC weaker?
if water is absorbed via saliva contamination
What is RMGIC composed of?
Powder (base)
Liquid (acid)
What is in the powder of RMGIC
Silica, aluminum, fluoride glass
pigments
barium glass
What is in the liquid of RMGIC?
polyacryclic acid
HEMA
tartaric acid
campherquinone photo initiator
Describe setting rxn of dual curing RMGIC
This is where the initial reaction is and acid base reaction (dissolution occurs)
Then it is light activated which results in formation of free radicals which initiate free radical addition polymerisation forming a resin matrix
acid base rxn continues for several hrs
Describe setting rxn of tri cure RMGIC
This is where acid base rxn occurs as normal (dissolution)
then a redox reaction occurs
light cure results in free radical addition polymerisation and then fomration of resin matrix
What are some properties of RMGIC?
Biocompatible
Good thermal expansion
low thermal conductivity
improved aesthetics (more translucent)
easy to use
fluoride releasing
What are some properties of GIC?
Fluoride releasing
Biocompatible
Good handling characteristics
Low modulus
Good thermal expansion
Low thermal conductivity
aesthetics meh
easy to use - bulk placement, bonds directly with no prep required
