Dental Cements Flashcards
WHY DENTAL CEMENTS?
(4)
caries
fractures
misalignment
prolong the life of the pulp in the war against oral bacteria- using protective coatings
prolong the life of the pulp in the war against oral bacteria- using protective coatings
(4)
varnish
base
liner
pits and fissure sealants
DENTAL CEMENT
substance that hardens to act as a base, liner, restorative material or luting agent (adhesive) to bind devices and prostheses to tooth structure or to each other
WHAT DO WE WANT A DENTAL
CEMENT TO BE?
(10)
biocompatible
non corrosive and inert
immune to acid attack
dimensionally stable
sets during the dental procedure
low surface tension; handles and palces easily
adapts and adheres to anatomy
insensitive to moisture during procedure
anti microbial/ F release
radiopaque
cost effective
immune to acid attack
insoluble
dimensionally stable
(2)
no cracking of tooth or device by expansion
no leaking because of shrinkage
WHAT MECHANICAL PROPERTIES FOR
THE CEMENT ARE NEEDED?
high values needed for:
(3)
cyclic fatigue
thermal cycling
strength
strength
(4)
tensile
compressive
flexural strength
shear
luting cements
(3)
permanent and provisional indirect restorations
ortho brackets
post and cores
restorative materials
permanent and provisional direct restorations
cavity liners and bases
pulp protection
multiple applications
no one cement can fulfill all requirements
LUTING CEMENT/AGENT
viscous material that fills the microscopic space between the abutment-prosthesis interface; upon setting, it forms a solid that seals the space and retains the prosthesis
Ideal properties of a permanent
luting agent
(8)
deal properties of a permanent
luting agent
1. *Low film thickness (25 m)
2. *Adequate strength (minimum 70 MPa)
3. *Low solubility (0.2% max. @ 24h)
4. *Reasonable setting time (2.5-8.0 min)
5. Adequate working time
6. Biocompatible, does not irritate pulp
7. Cariostatic
8. Adhesion to tooth structure and restorative materials
*ADA and ISO specification requirements
physical bonding
very weak interaction, secondary bonds
-van der waals forces, hydrogen bonds
chemical bonding
strongest bond, primary bonds
-limited occurrence, dissimilar materials
-ex, composite bond to adhesive bond agent
mechanical bonding
interlock undercuts, surface irregularities
-micromechanical retention
-ex: luting agent/tooth/crown, adhesive bond agent/tooth
MICROMECHANICAL RETENTION:
LUTING CEMENT VS ADHESIVE BOND
AGENT
LUTING CEMENT
cement locking into microscopic irregularities in prepared tooth surface and the internal surface of the crown
-non resin cements
-very low bond strength, 1-5 mpa
MICROMECHANICAL RETENTION:
LUTING CEMENT VS ADHESIVE BOND
AGENT
ADHESIVE BOND
AGENT
enamel: resin tags into etched enamel
dentin: hybrid layer
-interdiffusion or micromechanical interlocking of resin with demineralized collagen of intertubular dentin
-20-30 mpa bond strength
Cement
Setting mechanism
CaOH
Acid-base reaction
Cement
Setting mechanism
Zinc oxide (ZO) eugenol
Modified ZO eugenol
ZO non-eugenol
Acid-base
Cement
Setting mechanism
Zinc polycarboxylate Acid-base
Acid-base
Cement
Setting mechanism
Zinc phosphate
Acid-base
Cement
Setting mechanism
Glass Ionomer (GI)
Acid-base
Cement
Setting mechanism
Resin-modified GI
Acid-base AND
polymerization
Cement
Setting mechanism
Resin cement (RC)
Unfilled or Filled
polymerization
LIQUID: ACIDIC COMPONENT
(3)
eugenol/noneugenol oils
polycarboxylic acid
phosphoric acid
POWDER: BASIC COMPONENT
zinc oxide (ZO)
fluroaluminasilicate (FAS) glass
types of luting cements
(4)
- ZINC-OXIDE EUGENOL AND NON-EUGENOL CEMENTS (ZO)
- POLYCARBOXYLIC ACID CEMENTS
- ZINC PHOSPHATE CEMENT
- RESIN-BASED CEMENTS
- POLYCARBOXYLIC ACID CEMENTS
(3)
zinc polycarboxylate cement
glass ionomer cement
resin modified glass ionomer
- RESIN-BASED CEMENTS
(3)
resin modified glass ionomer
unfilled resin cements
filled resin: composite resin cements
ZNO-EUGENOL CEMENTS
types (3)
indications (1)
regular ZEO
reinforced ZEO
ZEO-EBA
temporary/intermediate cementation
INC OXIDE EUGENOL CEMENTS
(ACID-BASE)
composition
powder: zn oxide
liquid: eugenol
modifications
- polymer-reinforced: IRM
- EBA, alumina
INC OXIDE EUGENOL CEMENTS
(ACID-BASE)
low strength
ZOE
-compressive: 2-15
-tensile: 1-2
ZOE (modified)
-compressive: 40-50
-tensile: 3-5
INC OXIDE EUGENOL CEMENTS
(ACID-BASE)
uses
temp or provisional cement and restorations
ZINC OXIDE – EUGENOL
powder
99% ZnO and radiopaque fillers
ZINC OXIDE – EUGENOL
liquid
oil of cloves
85% eugenol
ZINC OXIDE – EUGENOL
rxn products
zinc oxide, zinc eugenolate
needs h2o to set
ZINC OXIDE – EUGENOL
no pulpal irritation
eugenol acts as sedative, obtundent
ZINC OXIDE – EUGENOL
ZEO unmodified, tempbond
temp cement
ZINC OXIDE – EUGENOL
ZOE polymer reinforced
IRM
-temp cement: decrease retention or increase time
-provisional/intermediate restoration
ZINC OXIDE – EUGENOL
not used prior to resin based permanent cement, why?
ZNO-EUGENOL
(6)
+ obtundent
+ slow setting
excess eugenol is irritant
shrinkage
low strength
solubility
excess eugenol is irritant
(2)
cytotoxic
potential allergen
ZINC OXIDE NON-EUGENOL CEMENTS
(4)
temp cement
eugenol replaced with other oils
used prior to permanent resin based cement
tempbond NE
tempbond NE (2)
slow set
low retention
ZINC POLYCARBOXYLATE CEMENT
(ACID-BASE)
reaciton
zn oxide + polyacrylic acid = zn polyacrylate (powder)
ZINC POLYCARBOXYLATE CEMENT
(ACID-BASE)
low strength
(2)
compressive, 55-67 mpa
tensile, 6-8 mpa
ZINC POLYCARBOXYLATE CEMENT
(ACID-BASE)
biological considerations
(2)
initial pH ~3, similar or lower than Zp PO4
minimal pulp rxn, large molecule not enter tubules
ZINC POLYCARBOXYLATE CEMENT
(ACID-BASE)
dentin bond strength
chelation interaction:
physical bond:
~2 mpa
cement carboxylate and Ca on tooth surface
interaction between - and + charges
ZINC POLYCARBOXYLATE CEMENT
advantages
(2)
-low pulpal irritation
-adhesion to tooth structure (more with enamel than dentin)
ZINC POLYCARBOXYLATE CEMENT
disadvantages (3)
-low strength
-more viscoelastic
-prosthesis dislodgment over time
ZINC POLYCARBOXYLATE CEMENT
marketed as a temp cement
(3)
-ultratemp
-can be used prior to resin cement (no poly inhibition)
-ultratemp rez: resin based
ZINC POLYCARBOXYLATE CEMENT
characteristics
(6)
oldest, still in use
gold standard for new cements
easy to manipulate
working time: 3-6 min
setting time <14 min
indications: luting (non adhesive cementation), fixed pros
ZINC PHOSPHATE (ZNPO4) CEMENT
(ACID-BASE)
reaction
zinc oxide (powder) + phosphoric acid (liquid) = zn phosphate
ZINC PHOSPHATE (ZNPO4) CEMENT
(ACID-BASE)(1878)
micromechanical bond to preparation surface and crown internal surface micro-irregularities
(3)
no chelation interaction
bond strength: 0.5-1.5 mpa
preparation retention and resistance form critical
ZINC PHOSPHATE (ZNPO4) CEMENT
(ACID-BASE)
no longer a major luting agent
(2)
possible current use: cement retained implant crowns
radiographic visibility, easier removal with less damage to implant surface
ZN PHOSPHATE CEMENT
powder
?75% zinc oxide <13% magnesium oxide
ZN PHOSPHATE CEMENT
liquid= aqueous solution of
38-59% H3PO4
2-3% AL phosphate
<9% zn phosphate
ZN PHOSPHATE CEMENT
reaction products
(3)
amorphous Zn3(PO4)4H2O matrix
zinc aluminophosphate matrix
residual zno particles
ZINC PHOSPHATE
exothermic
(3)
use chilled glass slab
mix over large area of slab
mix in increments
ZINC PHOSPHATE
(3)
exothermic
create stringy consistency
remove excess after set
ZN PHOSPHATE CEMENT
(4)
+ thermally protective
acidic
exothermic rxn
some solubility with acids
GLASS IONOMER (GI) CEMENT
(ACID-BASE)
composition
powder: FAS
liquid: polycarboxylic acid/h2o
GLASS IONOMER (GI) CEMENT
(ACID-BASE)
strength
compressive:
tensile:
90-140 mpa
6-7 mpa
GLASS IONOMER (GI) CEMENT
(ACID-BASE)
— release
fluoride
GLASS IONOMER (GI) CEMENT
(ACID-BASE)
bond strength
3-5 mpa
-chelation, cement carboxyl and ca in apatite
GLASS IONOMER
(GI) CEMENT
(ACID-BASE)
posts cementation hypersensitivity
brands (2)
early protection (varnish to prevent dehydration of initially set cement
ketac-cem, glasslute
ACID-BASE CEMENT COMPONENTS
liquid
acidic component
-eugenol/non eugenol oils
-polycarboxylic acid
-phosphoric acid
ACID-BASE CEMENT COMPONENTS
powder
basic component
-xinc oxide
-FAS glass
GLASS IONOMER CEMENT
combo of tech of silicate cememnt and polycarboxylate reaction
GLASS IONOMER CEMENT
glass powder
Ca-F-Al-silicate
-optional Ba, Sr for radiopacity
-optional Ag, Zn
-powder size <25mm
GLASS IONOMER CEMENT
liquid
water solution of
-50% polyacrylic-itaconic copolymer
-optional water-soluble polymer
-citric, maleic and tartaric acids
GI CEMENT
(3)
-affixing devices )ortho bands)
-fluoride release
-requires protection from dilution or evaporation during setting
GIC -CLINICAL
(7)
fluidity like Zn PO4
chill the powder and slab
avoid liquid evaporation
remove smear layer created by preparation instruments
dont dehydrate tooth
protect cement from excess or frequency of H2O during set (apply copalite on exterior)
remove excess immediately (avoid adhesion in unwanted areas)
RESIN-MODIFIED GLASS IONOMER (RMGI)
CEMENT (ACID-BASE + POLYMERIZATION)
composition
(3)
powder: FAS glass
liquid
photoactivator (light activated only)
RESIN-MODIFIED GLASS IONOMER (RMGI)
CEMENT (ACID-BASE + POLYMERIZATION)
liquid
polycarboxylic acid/h2o
resin monomers, vary with products
-hema, bis-GMA
-replace some of the h2o of conventional GI
RESIN-MODIFIED GLASS IONOMER (RMGI)
CEMENT (ACID-BASE + POLYMERIZATION)
setting reactions (2)
acid base rxn
monomer polymerization: light, chemical, dual activated
RMGI CEMENT
strength
compressive: 150-200
tensile: 13-24
RMGI CEMENT
fluoride release
from….
RMGI CEMENT
bond strength
5-10 mpa
RMGI CEMENT
powder/liquid system
potential for
brands (3)
dispending error
rely z, fuji plus, CX plus
RMGI CEMENT
paste/paste systems
(6)
2 tube dispenser
mix on pad
quicker dispensing
less dispensing error
mix within 30 s
brands: rely x plus, fuji cem
CEMENTATION WITH RMGI:
POWDER/LIQUID SYSTEM (RELY X)
(11)
- gently shake powder bottle to fluff powder
- dispense powder before liquid
- equal number powder scoops and liquid drops
(3 scoops for crown, 6 for FPD, 2 abutments) - hold bottle vertically to dispense liquid
- mix powder into liquid within 30 s
- load the crown with cement
(spread cement onto all internal surfaces) - working time is 2.5 minutes
- seat the crown
- wait at least 3 min after placement
- after cement is completely set, remove excess (scaler, explorer, knotted floss)
- gingival crevice, remaining cement (any cement that is not removed will be very irritating to the tissue)
- seat the crown
(2)
maintain pressure on restoration while cement is setting
maintain dry field: cotton rolls, suction
RESTORATION CEMENTATION POTENTIAL
PROBLEMS
(5)
premature contacts
pulpitis
loosening of the restoration
recurrent caries
restoration incomplete seating, often linked to other problems
incomplete seating factors
(4)
cement viscosity; pseudoplasticity
vibration
venting, preparation groove
seating force
cement viscosity; pseudoplasticity
restoration morphology
-onlay vs crown, less force required
seating force
excess force leads to dentin rebound and potential restoration. dislodgement
RMGI INDICATIONS
(6)
cavity liners, base
pit and fissure sealants
core buildups
restorative
adhesive
retrograde root filling materials
RMGI INDICATIONS
(6)
cavity liners, base
pit and fissure sealants
core buildups
restorative
adhesive
retrograde root filling materials
adhesive
(2)
ortho brackets, crowns
repair amalgam
resin cements
(5)
1950s, 1970s
based on methyl methacrylate
chemical (self) cure
light cure
dual cure
RESIN CEMENTS
(12)
looks esthetic, transulcent, shades to match tooth
insoluble
fast curing or slow curing formulas
good for ceramic restorations
strong and insoluble
shrinkage: leakage
higher film thickness
more complex clinically
incomplete conversion of monomer
poorer strength, more irritation
odor, allergies
wear of resin
RESIN CEMENT USES
(2)
protheses cementing
ortho brackets
protheses cementing
(3)
metal
polymer
ceramic
COMPOMERS
(3)
combo of resin cements with a dash of GIC
polyacid liquid monomers and resin monomers (water free)
usually light curing