Dental pt2 Flashcards
Func dental cements
luting agent (bonding material)
cavity liners
restorative materials
Charac cement
multipurpose material
Types cement
diff cement - diff application - diff physical prop, appropriate clinical manipulative charac
Cond acceptable performance luting, restorative cement
NO dissolution oral envi
strong bond - mech interlocking, adhesion
high strength tension, shear, compression
high fracture toughness
good biocompatibility
Types cements based on matrix forming species
- Phosphate
a. Zn phosphate
b. Zn silica phosphate - Phenolate
a. ZnO eugenol: Simple ZnO eugenol, reinforced ZnO eugenol, EBA ethoxy benzoic acid (Phenolate -> phe -> E -> eugenol)
b. Ca(OH)2 salicylate (pheNO -> OH -> Ca(OH)2) - Polycarboxylate
a. Zn polycarboxylate
b. Glass ionomer - Acrylate
a. Polymethylacrylate
b. Dimethylacrylate: filled, unfilled
Kelate forming rxn
Phosphate
Phenolate
polycarboxylate
Free radical poly
acrylate
Use of Zn phosphate cement
luting agent
cavity liners
Zn phosphate compo.
powder:
ZnO
MgO
Ca(OH)2
pigments
(phOs -> lots of O -> ZnO, MgO, Ca(OH)2)
liquid:
H3PO4
H2O
(phosphate -> phosphoric -> H3PO4 -> have acid, need H2O)
Zn phosphate formation need
Al low level need for formation
Zn: moderator
Zn phosphate cement rxn
ZnO + H3PO4 -> amorphous Zn phosphate + ZnO core
Properties, manipulation Zn phosphate cement
far from ideal - use as standard against new cements
easy manipulation
(1st one of the list -> use as standard)
Properties strength Zn phosphate cement
increase powder p/l - increase strength
recommended p/i ratio: 2.5-3.5g/ml
24h -> min comp strength: 60mpa
(Zinc -> ring -> ring bell -> Lorelai ring -> 25-35 yrs old - dinner 60min -> min comp strength:60MPA)
Properties solubility Zn phosphate cement
23h -> solubility in distilled H2O (0.04-3.3%) for inferior meterial
standard solubility: 0.2%
solubility oral cond: 20-30X >
Properties dimensional change Zn phosphate cement
dimensional change -> slits at tooth - cement; cement - restorations interfaces
Properties pH Zn phosphate cement
freshly mixed: 1-2
setting time: 1-7
1h -> ph4
24h -> ph6-7
(less chua)
Effect of low pH
free acidity mix + osmotic movement fluid thru dentinal tubules -> pain
Prolomged pulpal irritation
Ad, disad Zn phosphate
mixed easily
strong mass from fluid consistency
pulp irritation
NO antibacterial action
brittleness
NO adhesion tooth structure
solubility oral fluids
(first one on the list -> NO antibacterial, pulp irritation)
Types modified Zn phosphate cement
Cu
Ag - silver phosphate
F
Si - silicophosphate - silica glass cement
Cu modified Zn phosphate cement
Cupric oxide CuO
Cuprous oxide Cu2O
Cuprous iodid
Cuprous silicate
Effect Cu modified Zn phosphate cement
highly acidic
-> higher pulpal irritation
higher solubility
lower strength
(Cu - in acid - high acidic - high solubility -> less strength)
Effect F modified Zn phosphate cement
stannous
in orthdontic cement
higher solubility
lower strength
reduce enamel solubility
anticariogenic effect
(F fluoride -> good for teeth -> anticariogenic -> reduce enamel solubility - still high solubility, low strength)
Simple ZnO Eugenol phenolate based cement use
temporary cementation
cavity liner (pediatric dentistry)
(simple , reinforced -> temporary, for kids - cavity liner)
Composition simple ZnO Eugenol phenolate based cement
powder: pure ZnO aka setting accelerators
liquid: purified ZnO + accelerator (alcohol/ acetic acid)
Rxn simple ZnO Eugenol phenolate based cement
ZnO + eugenol -> + H2O -> Zn eugenolate (eugenate)
Volumetric shrinkage ZnO Eugenol phenolate based cement
0.9%
Thermal expansion ZnO Eugenol phenolate based cement
3510^06/Celsius
(around normal temp10^6)
Biologic effect ZnO Eugenol phenolate based cement
deep cavity: anodyne (reduce pain) effect on pulp
direct contact CT: irritant
eugenol: allergen
(eugene - helps heal mentally but irritates physically aka deep cavity - anodyne effect ; direct contact CT: irritant, eugenol: allergen)
Ad simple ZnO Eugenol phenolate based cement
good sealing
resistance marginal penetration
obtundent effect pulp tissue
disad ZnO Eugenol phenolate based cement
low physical prop
(eugene -> cold -> low temp -> low physical prop)
use reinforced ZnO Eugenol phenolate based cement
luting agent (except later restoration)
temporary filling material
cavity liners
(reinforced -> more complicated -> can be used as luting)