Dr. Johnston (Provisional Restorative material) Flashcards
advs of resin based material
- ease of formation
- translucency
- thermally insulating
disadvs of resin based material
- exothermic reaction
- shrinkage
- variable efficiency
- High co-efficient of thermal expansion
- low toughness
thermoset
irreversible cross linking
category of polymer
thermoplastic
no cross linking and is reversibly controlled by temp
category of polymer
molecule capable of COVALENT BONDING with another monomer
monomer
molecule formed by many monomers
polymer
polymer formed from 2 or more TYPES of monomers
co-polymer
type of polymerization that has NO by products
addition polymerization
*free radical is most common
type of polymerization with by products?
condensation
chemical stages of polymerization
- initiator activation
- monomoer activation
- polymer growth
- termination
types of initiator activation
- heat activation (long working time, uniform and efficient, requires heating EQUIPMENT)
- chemical activation (short working time, not as efficient as heat
- light activation (infinite working time, hard for light to reach bottom of larger restorations)
in the activation of a monomer, what cause the heat of the reaction?
change of a double bond to two single bonds
what is dual functionality?
used in dental resins polymer growth, cause CROSS-LINKING between 2 growing polymers (thermoset)
the greater the size of methacylate monomers, the less shrinkage and heat of retain, but the mechanical properties are _____
lower
what causes a polymer to stop growing?
free-radical transfer
contaminants (eugenol) can cause this prematurely
