materials for cementation Flashcards
define luting cement
is a solid paste
what must the luting cement be
Must not harm the tooth or tissues
Must allow sufficient working time to place the restoration
Must be fluid enough to allow complete seating of the restoration
Must quickly form a hard mass strong enough to resist forces
what does the cement do
Seals the interface between the tooth and the restoration
Acts as a barrier against bacterial microleakage
Holds the tooth and restoration together through some from of attachment:
what type of attachment does the tooth and the restoration bind by
mechanical
chemical
mechanical and chemical
how do we cement
1) Isolate and dry the prep
2) Clean and dry the restoration
3) Mix cement
4) Place the restoration
Seat restoration with thumb and apply pressure
what are the biological properties of a cement
→ No interaction with oral fluids/tissues → Non toxic → Biocompatible → Low allergic potential → Prevention of microleakage → Inhibition of caries/plaque
what are the mechanical properties of a cement
colour stability
radiopacity
why is low film thickness important
improves retention
gives close tooth restoration relationship
what thickness should the low film thickness be
25 microns
why might be the failure of luting cement
micro leakage OR catastrophic failure
what can micro leakage lead to
ingress of bacteria leading to
bacterial disease
describe zinc phosphate
sets by acid base reaction
compressive strength is 80-100 MPa
tensile strength is 5-7Mpa
modulus of elasticity is 13 GPA
what is the reaction between glass ionomer cements
aluminum fluorosilicate glass particles and polyalkenoic acids
describe the reaction of resin modified glass ionomers
leads to formation of a metal polyacylate salt and polymer
acid base reaction
describe RMGIC
less soluble
releases fluoride- good for high caries pt or temporisation
