Luting

Luting cements
Presented by
Dr. Arunima Upendran
1st MDS

Contents
 Introduction
 History
 Classifications
 Conventional luting cements
 Contemporary luting cements
 Recent advances
 Review of literature
 References

Acid-base reaction—Chemical reaction between a
compound with replaceable hydrogen ions (acid) and
a substance with replaceable hydroxide ions (base)
that yields a salt and water; for aqueous cements, the
liquid is an acid and the powder is a base.

• Luting is derived from a greek word LUTUM –
meaning mud.
• Primarily cements were used to fill the gap
between restoration and tooth structure. There
was no bonding.

1850s
Zinc
oxide
eugenol
1870s
Zinc
phosphat
e
1960s
Zinc
carboxyla
te
1972
Glass
ionomers
1992
Resin-
modified
glass
ionomers

History…
1873- Silicate cement by Fletcher
1873- Zinc oxide and clove oil by Chisolm
1879- Zinc phosphate cement by Dr Pierce
1930- Calcium hydroxide paste by Hermann
1968-Polycarboxilic cement by Dennis Smith
1971-Glass ionomer cement by Wilson and Kent

QUALITIES OF IDEAL
CEMENT
It should have very low resolution ratios within
the liquids inside the mouth.
It should be well adapted to living dental tissues, it
should contain no pulp irritating toxic material and it
should further have anticariogenic qualities.
In order to reach the smallest details between
restoration and tooth, it should possess low
viscosity and film thickness.
It should have sufficient light transparency

5. It should be resistant against mastication
forces and pulling forces formed through the
effect of gummy foods.
6. It should provide sufficient heat insulation
to protect living tooth from thermal effects.
7. It should be able to bond to hard dental
tissues.
8. It should have a long shelf-life.
9. It should give sufficient working time and
be easy to manipulate.

Based on knowledge
and experience of
use (Donovan)
b. Contemporary
(resin-modified
glassionomers,
resin)
a. Conventional
(zinc
phosphate,polyca
rboxylate, glass-
ionomer)

Water based cements
o Glass & Resin modified glass ionomer
o Zinc Polyacrylate
o Zinc Phosphate
Resin based cements
o Composite & adhesive resin
o Compomers
Oil based cements
o Zinc Oxide Eugenol
o Non Eugenol -Zinc Oxide

Water based cements
1) Glass & Resin modified glass ionomer cement :
Class V restoration
- Retention of- Conventional alloy based restoration
Orthodontic bands
Alumina or zirconia based all ceramic restoration
- High strength bases
- Long term provisional restoration
2) Zinc Polyacrylate:
- Retention of -Conventional alloy restoration
-Orthodontic bands
-Pediatric stainless steel crown
3) Zinc phosphate :
- Retention of- Conventional alloy based restoration
-Orthodontic bands

Resin based cements
1. Composite & adhesive resin :
- Bonding- Conventional alloy based restoration
-Ceramic crowns, bridges ,veneers, inlays,
onlays.
- Post & cores
- Retention of - Provisional restoration
- Orthodontic bands
2. Compomers:
- Bonded conventional alloy based restoration
- Retention of - Alumina or zirconia based all ceramic
restoration
- Orthodontic bands

Oil Based Cements
Zinc Oxide Eugenol :
High strength bases
Provisional restoration
Root canal sealers
Gingival tissue packs
Surgical dressing
Non Eugenol -Zinc Oxide:
Provisional restoration
Root canal sealers
Gingival tissue packs
Surgical dressing

Based on the bonding mechanism
(Williams O'Brien. 2002 & Richard van
Noort)
Phosphate based :
Zinc phosphate cement
Modified zinc phosphate cement
 Fluoridated cement
 Copper cement
 Silicophosphate cement
Phenolate based :
Zinc oxide eugenol cement
Reinforced zinc oxide eugenol
EBA and other chelate cements
Calcium hydroxide chelate cement

Polycarboxylate based:
Zinc polycarboxylate cement
Glass ionomer cement
Methacrylate based:
Acrylic cements
BIS-GMA type cements

Classification based on setting reaction
( Skinners)
Acid Base Reaction –
Zinc phosphate
Zinc polycarboxylate
Zinc oxide eugenol
Light / Chemical activities
Polymerization and acid base reaction
Resin modified glass ionomer cement
Compomer
Resin cement.

Classification (E.C. Combe 6th
edition)
Acid base reaction cements.
Zinc phosphate
Zinc polycarboxylate
Zinc oxide eugenol
Silicate
Polymerising materials
Acrylic polymer
Cyanoacrylates
Dimethacrylate polymers
Polymer ceramic composites
.

Other materials
i) Calcium hydroxide
ii) Guttapercha
iii) Varnishes

Characteristics of Abutment -
Prosthesis Interface
• When two relatively flat surfaces brought into contact,
space exists on microscopic scale, there are peaks and
valleys
• There are only point contacts along the peaks
• Main purpose of cement is to fill this space completely
• If cement is not fluid enough voids can develop around
deep valleys

Procedure for cementation of
prostheses
• To be effective a Type-I cement must be fluid and be
able to flow into a continuous film of 25 um thick or less
without fragmentation
• The cement paste should coat the entire inner surface of
the crown and extend slightly beyond the margin. It
should fill about half of interior crown volume
• Moderate finger pressure should be used to displace
excess cement and to seat the crown

 Variables that can facilitate seating of prosthesis include
• Using a cement of lower viscosity
• Increasing the taper of preparation
• Decreasing the height of crown preparation
• Vibration

Removal of excess cement
• Removal of excess cement depends on properties of
cement used –
• If cement sets to a brittle state and does not adhere to
surrounding surfaces,tooth and prosthesis, it is best
removed after it sets . This applies to Zinc phosphate
and ZOE cements
• For cements which are capable of adhering chemically
like GIC, polycarboxylate and resin cement ,coat
surrounding surface with petroleum jelly and remove
excess as soon as seating is completed

Dislodgment of prosthesis
• Recurrent caries may occur
• Disintegration of cement can result from
fracture or erosion of cement
• In oral environment , cement layer near the margin can
dissolve and erode leaving a space. This space can be
susceptible to plaque accumulation and recurrent caries

Introduced in 1903 as anterior filling materials.
Silicates are attacked by oral fluids and in time degrade,
They may not be considered permanent restoration.
The uses of silicate cements diminished with the advent
of composite resins and development of GIC.

Composition
Powder:
Silica
Alumina
Fluoride compounds
Calcium salts
Liquid :
Phosphoric acid
Water
Buffer salts
 Fluoride Flux - To permit proper sintering of the other
ingredients.

Setting Reaction
cement matrix inclusive of Fl salts
Metal ions precipitate as phosphate
Powder attacked by acid liquid releasing Ca, Al, Flions
Powder mixed with liquid

Advantages
It exhibit good esthetic
qualities .
Anticariogenic property.
Analogues to topical
applied fluoride solution.
Disadvantages
It lacks stability in oral
fluids with loss of esthetic
qualities
Rubber dam is essential
for successful silicate
restoration.
Irritant to pulp.
33

• Oldest of the luting cement -1878
• Longest clinical track record
• Serves as a standard with which newer materials can be
compared
• Supplied as a powder and liquid.

POWDER
– Zinc oxide - 90%
– Magnesium oxide – 9-10 %
– Bismuth trioxide, Barium oxide – traces
sintered at temperatures between 1000deg Celsius
and 1400 deg Celsius -> cake -> fine powder
particle size -> setting time

Liquid
– Phosphoric acid
– Water
– Aluminium Phosphate
– Zinc Phosphate (some times)
Water controls the ionization reaction of acid - in turn
influence the rate of acid base reaction
Acid content of the liquid - 33% approximately.

CLASSIFICATION
(Anusavice 9th edition )
Type I
-Fine grained for luting
-Film thickness should be less than 25 um
Type II -
- Medium grained
- Film thickness 40um
- High strenght thermal insulating
base

Physical Properties
Compressive strength
:104MPa
Tensile strength:5.5MPa
Thermal conductivity :
3.11 mcal.cm/cm2.sec.K
• More soluble in dilute organic acids
Low water solubility
0.04wt%
• Quiet stiff & resistant to elastic deformation
• Loss/Gain water content compressive tensile strength.
Modulus of
elasticity:13.7GPa

Biological properties
Acidity of cement is quite high during the time of application -
presence of phosphoric acid 2 min after the start of mixing , Ph is 2
increases rapidly
reaches about 5.5 in 24 hrs Pulpal damage can occur during first
few hours High heat production during setting of the cement can
also cause pulpal injury.

Manipulation
Dispense the cement P/L :1.4
gm / 0.5 ml.
Divide the powder in one
corner of the glass slab into
increments depending on
product.
Dispense the correct amount of
liquid, to area of the slab away
from the powder.
Add the powder to liquid in
portions at 15 sec intervals for a
mixing time 60-120 sec

Mix it over a large area of
the slab with a flexible
metal spatula.
Test the consistency of the
cement before adding
the last portion of powder.
Only part of that portion
of powder may be
necessary to reach the
desired consistency.
The cementing strings
about one inch above the
slab.

• String test – 2-3 cm
• Starts and ends with small increments
• Three consistency- luting ; putty ; band seating

Frozen Slab Technique
Practical way to increase the working time and reduce
the setting time of zinc phosphate cement.
50% increased powder/liquid ratio.
Mixing in a frozen glass slab at 60c or freezed to -100c.
Effective when multiple castings are to be cemented.
Excess of cement is easy to clean up .
But decrease in compressive strength.
 Wt – 4-11 mins
 St 20-40% shortened

SETTING REACTION
and surrounds with un reacted particle
Zinc alumino phosphate gel
Al & Zn ions react with phosphoric acid
Release of zinc ions & reaction of Al with phosphoric acid
Phosphoric acid attacks the surface
Powder & liquid mixed
Thus the set cement is a cored structure consisting primarily of unreacted Zinc Oxide
particles embedded in a cohesive amorphous matrix of zinc aluminophosphate.
Water is critical to reaction

• Changes in composition and reaction rates might occur
due to degradation of the liquid or water evaporation
from the liquid
• Liquid degradation effects are exhibited as clouding of
the liquid
• Loss of water from acid increases the setting time

Applications
• Luting permanent restorations
• Bases
• Cementation of orthodontic bands
• Provisional restoration

Advantages
• High comp str
• Good thermal and
electrical insulator
• Low solubility
Disadvantages
• Brittle
• Low tensi str
• Cannot be used to lute
full ceramic
• No chem adhesion
• Pulp irritant
50

Zinc silico phosphate
 Combination of zinc phosphate & silicate cement.
 Contains small amounts of mercury compounds.

Composition:
Silicate glass & minor amount of zinc oxide,13-25% fluoride
Liquid contains;
50% phosphoric acid,45% water,4-9% zinc, 2% Al.
Advantages :
Better & toughness than zinc phosphate.
Fluoride release & degree of translucency.
Lower solubility & better bonding.
Disadvantages :
Less satisfactory mixing & rheological properties
Leading to higher film thickness & greater potential irritation.
 Used for cementation orthodontic bands & restoring non vital
teeth

• 1960
• First - adhesive bond to tooth structure.
• Supplied as
– Powder and liquid

Powder
• Zinc oxide – 72%
• Magnesium oxide – 7%
• Other oxides like bismuth
and aluminium
• Stannous fluoride -
• Basic ingredient
• Modifier , aids in sintering
• Increase strength,
modifies setting time,
imparts anticariogenic
properties
55

Liquid
• Liqueous solution of polyacrylic acid (32-48%)
Or
• Copolymer of acrylic acid with other unsaturated
carboxylic acids (itaconic , maleic , tricarballylic acids)
• Molecular weight – 25,000 – 50,000 daltons
• Itaconic & tartaric – prevent gelling
• Viscosity of liquid adjusted- molecular size : sodium
hydroxide (ph)

Available as:
• p/l
• P & liquid (freeze dried) + distilled water
• Encapsuled

Manipulation
• A cooled glass slab / powder
• 1.5 parts of powder to 1 part of liquid by weight
• Liquid not dispensed , before the start
• Loss of water, increases viscosity
• Powder is rapidly incorporated into the liquid in large
quantities
• Mixing time is with in 30 – 60 sec ,with half to all of
powder incorporated at once to provide the maximum
length of working time
• Surface - glossy , acid present to provide sufficient
carboxylic groups to bond.

Glossy Appearance
Dull Appearance

Chemical reaction
When acid comes in contact with powder ,
acid reacts and releases zinc, magnesium,
and tin ions
They bond to the polymer chain , through the
carboxyl groups
These ions also react with carboxylic groups
of adjacent poly acid chains
Cross inked salts are formed

Bonding to tooth structure
• Poly acrylic acid reacts with calcium ions via carboxyl
groups on the surface of enamel or dentin.
• Bond strength greater on enamel than dentin.
• Enamel 3.4-13.1MPA Dentin 2.07MPA

Working and Setting time
• Working time : 2.5 min
• Setting time : 6-9 min
• Lowering the temperature of chemical reaction can
increase the setting time.

Mechanical Properties
Compressive strength : 55-67 Mpa
Tensile strength : 2.4-4.4 Gpa
Modules of elasticity is lower then zinc phosphate cement 5.1GPa
More soluble than zinc phosphate cement 0.06%
More soluble in organic acids.
Not as brittle as zinc phosphate cement
Excess removal is difficult.

Biological Consideration
• Pulpal response termed as mild
• Ph of liquid is 1- 1.7
• Freshly mixed cement – 3-4
• After 24 hrs – 5 -6

Applications
• Primarily for luting permanent restorations
• As bases and liners
• Cementation in orthodontic bands
• Peado stainless steel crowns

Advantages
• Chemical bond
• Mild pulp resp
• Anticariogenic
Disadvantages
• Set – rubbery consist
• Short wt & st
• Compre stren poor
compared to znp
66

Introduction
• These cements have been extensively used in dentistry
since 1890’ s
• They are least irritant of all dental cements
• Have an obtundant or sedative effect
• Compatible with the hard and soft tissues of the mouth

Classification
• Type 1 ZOE – for temporary cementation
• Type 2 ZOE – permanent cementation
• Type 3 ZOE – temporary filling material , thermal
insulation
• Type 4 ZOE – Cavity liners

Powder
• Zinc oxide – 69%
• White rosin – 29.3%
• Zinc stearate – 1%
• Zinc acetate – 0.7%
• Magnesium oxide
• Principle ingredient
• Reduce brittleness
• Accelerator , plasticizer
• Accelerator , improves
strength
• Added in some powders
70

• Liquid:
– Eugenol – 85% - reacts with zinc oxide
– Olive oil – 15% - plasticizer

Setting reaction
• First , hydrolysis of zinc oxide to its hydroxide
• Water is essential for reaction to proceed
• reaction is a acid base one,
• Zinc hydroxide combines with eugenol to form a chelate
ZnO + H2O → Zn(OH)2
• ZINC EUGENOLATE
• Forms an amorphous gel, which later tends to crystallize.
• Structure : particles of unreacted zinc oxide embedded in
a matrix of zinc eugenolate
Zn(OH)2 + 2HE → ZnE2 + 2H2O

Manipulation
• p/l ratio 4:1 to 6:1 by wt
• the bulk - incorporated into the liquid -spatulated
thoroughly in a circular motion - a stiff bladed spatula
• Small increments - until the mix is complete –
consistency

• Setting time - 4-10 mins
• Complete setting reaction between zinc oxide and
eugenol takes about 12 hrs
Factors affecting setting time:
• Particle size – smaller particle size, set faster
• Accelerators – alcohol , glacial acetic acid , and small
amounts of water
• Retarders – glycol, glycerine
• Temperature – high temperature , accelerate setting
• Powder/ liquid ratio – higher the ratio, faster the set

Physical properties
• Relatively week cements
• Compressive strength : Ranges from 3-4mpa to 50-
55mpa
• Tensile strength : 0.32 to 5.8mpa
• Modules of elasticity : 0.22 – 5.4 mpa
• Excellent thermal conductivity
• Solubility of the set cement is high - disintegrate in oral
fluids - Solubility is reduced by increasing p/l ratio

Biological properties
• Least irritating of all dental cements
• Ph is 6.6 – 8
• Pulp response is termed as mild
• They inhibit the growth of bacteria , have an anodyne or
soothing effect on pulp , in deep cavities, hence reduces
pain

Modifications of ZOE
Resin Reinforced Zinc Oxide Eugenol Cement
EBA and other Chelate Cements

Modified Materials
• Polymer reinforced ZOE
• introduced in an effort to increase the mechanical
properties of zoe.
• Contains Zinc Oxide and finely divided natural or
synthetic resin like poly methyl methacrylate resulting in
good strength, improved abrasion resistance and
increased toughness
• Luting agent, Base, temporary filling material and as a
cavity liner.

RESIN REINFORCED ZINC OXIDE
EUGENOL CEMENT
 COMPOSITION
POWDER :
Zinc powder – 80.0%
Poly methyl-methacrylate – 20.0%(bond to other
components)
Zinc stearate - traces (accelerator)
Zinc acetate
Thymol & hydroxyquinoline – traces (antimicrobial agent)
LIQUID:
Eugenol – 85%
Olive oil – 15% -(as plasticizer ,masks irritating effect of
eugenol).

PROPERTIES
Film thickness - 25-75 um
Compressive strength - 35-55 MPa
Tensile Strength - 4 MPa
Modulus of elasticity - 2-3000 MPa
Water immersion reduces the mechanical properties due to loss of eugenol.
Mechanical retention of crowns of ZOE cement is less than Zinc phosphate cements.
An 83.5% success rate was noted for polymer reinforced cement after 7 years.
ST 7-9 min
WT 5 min
MT 2 min

EBA AND OTHER CHELATE
CEMENTS
COMPOSITION
Powder
ZnO
Aluminium oxide/other mineral fillers – 20-30%
Polymeric reinforcing agent (poly methyl methacrylate)
Barium sulphate - radiopacity
Liquid
O- ethoxy benzoic acid 50- 60%
Eugenol – Remaining part

PROPERTIES
Working time and setting time – 7-13 min.
Film thickness – 40-70 um
Tensile strength – 6-7 MPa
Modulus of elasticity – 5000 MPa
Shows visco -elastic properties with very low strength and
large plastic deformation at slow rates of deformation at
mouth temperatures (37 C)
This is why EBA cement retention values for orthodontic
bands, although superior to those of other zinc oxide
eugenol type materials, are considerably less than those
of zinc phosphate cement.
Exposing EBA cements to moisture results in greater oral
dissolution than with other cements.

Advantages
• Easy manipulation
• Long working time
• Good flow & strength
characteristics
• minimal irritation to the
pulp
• Best suited to luting of
restorations with good fit
retention where there is
no under stress and for
cavity bases.
Disadvantages
• More critical proportioning
• Hydrolytic breakdown in
oral fluids
• Liability to plastic
deformation
• Less retention than zinc
phosphate cements
84

Applications
Luting agent
Cavity bases

Non- Eugenol cement
(Cavit)
A premixed non eugenol paste used for temporary
restorations & cavity bases.
Contains
Zinc oxide
Zinc sulphate
Calcium sulphate
Glycol acetate
Poly vinyl acetate
Triethanolamine
Red pigments

Setting reaction initiated by saliva & water.
Better sealing into cavity walls due to hydroscopic
properties.
Minimum thickness of at least 3 to 3.5 mm required.
It is not satisfactory material for cementation.
When inserted into dry cavity it creates negative
pressure, causing aspiration of odontoblast leading to
pain.
PH same as ZOE.

Zitemp - Quick Set ZOE
Easy mix rapid setting zinc oxide - eugenol cement for
thermal insulation and temporary restoration.
Indications:
• Ideal temporary sealant and filling material for cavities
after removal of carious dentine before permanent
restoration
• Perfect cavity liner
• Temporary fixation of crowns and bridges
• Ideal cavity liner under most restorative
materials

Composition:
• Powder : Zinc Oxide
• Liquid : Eugenol, zinc acetate excipients
 Easy mix powder liquid composition
 Rapid setting
 Effective thermal and chemical insulator
 High compressive strength
 Excellent cavity liner compatible under most restorative
materials

• The invention of glass ionomer cement was done in
1969.first reported by Wilson and Kent in 1971.( ASPA I)
• Luting agent ASPA IVa in 1975 by Crisp and Abel
• Water activated luting cements in 1984 by Mc Lean et al

Other names
• Glass ionomer-term coined by wilson & kent
glass-alumino silicate glass particles
ionomer-poly carboxylic acid.
• ISO terminology- poly alkenoate cement.
• Since its extensive usage to replace the dentin ,has given
different names;
Dentin substitute
Man made dentin
Artificial dentin

Composition
• The glass ionomer powder is an acid soluble calcium
fluoroalumino silicate glass - ion leachable glass.

LIQUID
• Polyacrylic acid --- 45 %
• Water --- 50 %
• Modifiers Itaconic acid --- 05 %
maleic acid
tricarboxylic acid
↓ viscosity , inhibits gelation.
• Tartaric acid.

• The raw materials are fused to a uniform glass by heating
them to a temp.of 1100 °C- 1500°C.
• Lanthanum,strontium,barium or zinc oxide additions
provide radio opacity.
• The glass is ground into a powder having particles in the
range of 15-50 μm.

 ROLE OF COMPONENTS IN POWDER
•The role of Al2O3 & SiO2 of the glass is crucial and is
required to be of 1:2 or more by mass for cement
formation.
•CaF2-Supplemented by the addition of cryolite
(Na3AIF6).
•This flux
-reduces the temperature at which the glass will fuse
-increases the translucency of the set cement.

• Fluoride is an essential constituent which
- Lowers fusion temp., acts as flux
- improves working characteristics & strength
- improves translucency
- improves therapeutic value of the cement by
releasing fluoride over a prolonged period
• Al3PO4-Improves translucency.
Apparently adds body to the cement paste

• The liquid is an aqueous solution of polymers
And copolymers of acrylic acid.
• In most of the current cements,the acid in the form of a
coploymer with itaconic ,maleic ,or tricarboxylic acids.
• polyacrylic acid-is the most important acid
contributing to formation of the cement matrix.
• Water-
• It is reaction medium.
• It serves to hydrate the siliceous hydrogel and the metal
salts formed.
• It is essential part of the cement structure. If water is lost
from the cement by desiccation while it is setting, the
cement-forming reactions will stop.

•Glass ionomer cements are water-based materials
•Plays a role in transporting calcium and aluminium ions to
react with poly acids.
•Types:
- Losely bound water
-Tightly bound water
•With the aging of cement, the ratio of tightly bound to
loosely bound water increases
•Accompanied by an in strength, modulus of elasticity and
in plasticity
•Cement is only stable in an atmosphere of 80% relative
humidity

• In higher humidities the cement absorbs water and the
consequent hygroscopic expansion can exceed the
setting shrinkage.
• Cement can lose water under drying conditions, however
leading to shrinking and crazing.
• Susceptibility to desiccation decreases as the cement
ages
• This is prevented if protected for about 10 to 30 mins
(depends on manufacturer).

Itaconic acid
• Itaconic acid promotes reactivity between the glass
and the liquid.
• It also prevents gelation of the liquid which can result from
hydrogen bonding between two polyacrylic acid chains

• Maleic acid
• A stronger acid than polyacrylic acid
• Causes the cement to harden and lose its moisture
sensitivity faster.
• More carboxyl (COOH) groups which lead to more rapid
polycarboxylate crosslinking

• Tartaric acid
• The 5% optically active dextro-isomer of tataric acid is
incorporated.
• It is also hardener that controls the PH of the set cement
during setting process, which in turn controls the rate of
dissolution of the glass.
• It facilitates extraction of ions from the glass.
• It typically increases the working time

Cement placement
Conditioning the Tooth Surface
• Dentin conditioning prior to placement of a GIC is done
primarily to remove the smear layer.
• GIC is better able to wet the dentin surface.
• Promotes ion exchange.
• Chemically cleans dentin.
• Increases surface energy.

Manipulation
Full spoon, no excess
Tip liquid bottle to side, then
invert completely
If water / tartaric acid, only 1 drop used

Liquid should not stay on
paper pad longer than
1minute (some of it may soak
into it)
Don’t mix beyond 30
seconds
The objective is – only wet
the particle – no dissolving it.
First half folded into liquid
in 10-15seconds
Second half incorporated in
15 seconds
Small mixing area

Loss of gloss/ slump test
GIC --- 60 – 90 sec
Resin-modified GIC --3 – 3.5 min

Working time & setting time
• It sets rapidly in the mouth that is within 3-5 min and
hardens to form a body having translucency that
matches enamel
• Setting time for type I –GIC – 5 -7 min
• Setting time for type II–GIC --10 min
• Film thickness should not exceed 20μm for luting agents

Setting reaction
•1. acid-base reaction
•2. light activated polymerisation
• ACID – BASE REACTION
• GIC formed by the reaction of three materials
Fluoro alumino silicate glass powder
Poly acrylic acid
Water
• An acid – base reaction occurs between the glass powder
and the ionic polymer.
•Water is essential because that is the medium through
which ion transfer takes place

• Chemistry of cement forming reaction from initial
mixing occurs in various stages
Decomposition of glass & migration of ions
• The glass particles are attacked at the surface by poly
acid which leads to withdrawal of the cations thus the
glass network breaks down to silicic acid.
• Principally Al3+, Ca2+, F-, are released and migrate
into aqueous phase of cement and form complexes

• Initially calcium complexes predominate but later
Aluminium complexes are more.
• pH and viscosity increases
Gelation and vulnerability to water
• At critical pH and ionic conc. Precipitation of insoluble poly
acrylates takes place.
• Initial set occurs due to calcium polyacrylate but
hardening of cement is due to slow formation of
aluminium polyacrylate

• When cement is not fully hardened Al, Ca, F and
polyacrylate ions may leach out leading to irretrievable
loss of cement matrix
• Calcium acrylate is more vulnerable to water. So the
freshly set cements are to be protected.
Hardening and slow maturation
• This process continues for about 24 hrs
• Undergoes slight expansion and increase in translucency
• Cement becomes resistant to dessication and strength
also increases for at least a year

Mechanism of adhesion
• Polyalkenoic acid attacks dentine and enamel: displaces
PO4,Ca ions
• Migrate into cement and develop an ion enriched layer
firmly attached to tooth structure.
• The bond strength to enamel is always higher than that to
dentin because of the greater inorganic content &
greater homogenity.

MECHANISM
• Smith – chelation of calcium(1968)
• Beech –
interaction between apatite and poly acrylic acid
polyacrylate ions
Ionic bonds with calcium ions in enamel and dentin

Acc. to Wilson(1974)
• Initial adhesion is by hydrogen bonding from free
carboxylic groups
Progressively these bonds are replaced by ionic bonds
• Polymeric polar chains of acids bridge the interface
between cement and substrate
Acc. to Wilson, Prosser and Powis(1983)
• Polyacrylate displaces and replaces surface phosphate
and calcium from hydroxyapatite
• An intermediate layer of Ca and Al phosphates and
polyacrylates is formed.

Properties of Glass Ionomer
cement (luting)
1.Setting time(min)
2.Film thickness(μm)
3. 24 hr compressive
strength (Mpa)
4. 24 hr diametrical tensile
strength (Mpa)
5.Elastic modulus(Gpa)
6.Solubility in water(Wt%)
7.Pulp response
• 7.0
• 24
• 86
• 6.2
• 7.3
• 1.25
• Mild to moderate
119

Biocompatibility
• Resistance to plaque because presence of F
• Pulp response to GIC is favorable
• Freshly mixed --- acidic pH 0.9 – 1.6 -- mild inflammation
resolve 10 -20 days
* used to protect mech / traumatic exposure of healthy pulp
• Glass ionomer cement showed greater inflammatory
response than ZOE but less than Zn phosphate cement,
other cements but it resolved in 30 days
(Garcia et al, 1981)

Thermal Properties
•The thermal diffusivity value of GIC is close to that for
dentin.
• The material has an adequate thermal insulating effect
on the pulp and helps to protect it from thermal trauma
Solubility & disintegration
• lower than ----Zn phosphate
Zn polycarboxylate
• In water --- less than Silicate cement
• Resin-modified GIC is less resistant to solubility

• Compressive strength < silicate cement
• Tensile strength --- higher -- silicates
• Hardness < silicates
• Wear resistance < composites
ESTHETICS
• Glass ionomer cement has got a degree of translucency
because of its glass filler
• Unlike composite resins, glass ionomer cement will
not be affected by oral fluids

Durability
Affected by the factors
• Inadequate preparation of the cement
• Inadequate protection of restoration
• Variable conditions of mouth
Failure rate is more a measure of clinician’s skill than
inherent quality of the material

• Some other properties
• Low exothermic reaction
• Adheres chemically to the tooth structure
• Less shrinkage than polymerizing resins
• Dimensional stability at high humidity
• F release discourages microbial infiltration
• Early moisture sensitive --- requires protection
• Poor abrasion resistance
• Average esthetic

RESIN MODIFIED GLASS IONOMER
CEMENTS
• developed by Antonucci, Mc Kinney and SB
Mitra.
• Addition of polymerizable resins to the
formulation to import additional curing process to
the original acid base reactions.

• Definition: RMGIC can be defined as a hybrid
cement that sets via an acid base reaction and
partly via a photo- chemical polymerization
reaction.
• Eg:Fuji II LC, Vitrebond, Photac –Fil, Vitremer,
FujiV.

Setting reaction
• 2 distinct setting reactions occur
• Acid base neutralization
• Free radicle MA cure. This can occur purely
via light cure or by a combination of LC and
chemical cure.
• Thus a cement can be termed
- dual cure if cross linking is via acid base + LC
or
- tri cure if its via acid base + Light cure +
chemical cure

Composition
Powder
• Ion leachable glass and
initiators for light
/chemical / both types of
curing
Liquid
• Water
• Polyacrylic acid modified
with MA & HEMA (15-
25%)monomers.
• The HEMA and water
content is low to
accommodate the
polymerizable
ingredients.
P:L = 3:1
128

1
1
2 3 4
5 6 7 8 9
10 11 12 13 14

properties
• Esthetics: improved translucency as the monomer
brings the refractive index of the liquid close to that of
the glass particle.
• Fluoride release: is same as that of the conventional
but the lining version shows higher F release
• Strength: The diametrical tensile strength is much
higher but compressive strength and hardness is lesser.

• Adhesion: to tooth is reduced- reduction in
carboxylic acid in the liquid and interruption of
chemical bonding due to the resin matrix.
-Adhesion to composites is increased - presence of
residual non-polymerized functional groups within
the RMGIC
• Micro leakage: high - polymerization
shrinkage+reduced water and carboxylic acid
content and reduces its wetting capacity

• Water sensitivity - reduced.
• The biocompatibility is controversial and
precautions such as placing Ca (OH)2 in deep
preparations should be taken - transient temp.
rise during setting

ADVANTAGES
• Long Working time and Snap setting
• Early water sensitivity is reduced
• Rapid development of early strength
• No etching is needed either to tooth for adhesion or
for the material if composite lamination is to be
done.
• Bonding to composite is higher
• Finishing can be done immediately
• F release
• Diametrical tensile strength is higher

DRAWBACKS
• Increased shrinkage with concurrent microleakage
• Low wear resistance as compared to composites
• Its controversial biocompatibility

POLYACID MODIFIED RESIN
COMPOSITE /COMPOMER
Fluoride
releasing
capability
of gic
Durability
of
composit
es
COMPOMER

• Definition: Compomer can be defined as a material
that contains both the essential components of GIC
but at levels insufficient to promote the acid –base
curing reaction in the dark
• Compomer is a combination of the word ‘comp’ for
composite “omer” for ionomer.

COMPOSITION
• one – paste system containing ion leachable glass &
polymerizable acidic monomers with functional groups of
polyacrylic acid & methacrylates in 1 molecule.
• NaF and some other fillers are also present for additional
F release.
• no water
• Glass particles are partially silanated to ensure bonding.

SETTING REACTION
Setting reaction occurs in 2 stages
• Stage 1: In contrast to RMGIC, a typical composite resin
network around filler particles forms on light activation
• Stage II : occurs over 2-3 months where by water from
the saliva gets absorbed and initiates a slow acid base
reaction with formation of hydrogels within the resin and
low level fluoride release.

PROPERTIES
• ADHESION: to tooth requires acid –etching as acid base
reaction for ion exchange which requires water does not
occur for some time after placement. Bond strengths
achieved usually approach the typical resin bonding
systems. It is = 18-24Mpa
• FLUORIDE RELEASE: is limited. It is significantly less
than Type II or RMGIC. F release usually starts after
about 2-3 months; it peaks initially and then falls rapidly
• PHYSICAL PROPERTIES: fracture toughness, flexural
strength and wear resistance are better than GIC but
less than composite.

INDICATIONS
• P& F sealant
• Restoration of primary teeth, class III and V lesions along
with cervical abrasions and erosions and intermediate
restorations
• Bases for composites, liners
• Small core build ups
• Filling of pot holes & undercuts in old crown preparations
• Root surface sealing

CONTRAINDICATIONS
• Class IV lesions
• Conventional class II cavities
• Lost cusp areas
• Restorations involving large labial surface
• ADVANTAGES
• Superior working characteristics to RMGIC
• Ease of use
• Easily adapts to the tooth
• Good esthetics

• Recently, a 2 component compomer is being marketed as
a P: L system or 2 paste system meant exclusively for
luting.
• These are self adhesive due to the presence of water
which starts off the acid base reaction.
• The powder contains the glasses, fluoride & chemical /
light initiators .
• liquid contains the monomers, Poly acrylic acid, water and
activators. These set via light chemical polymer as well
acid base reaction.

To summarize the differences between
the three types of materials
• Fluoride Release and Rechargability
GICs>RMGICs>PAMCRs
• Wear Resistance
PAMCRs>GICs>RMGICs
• Strength
PAMCRs>RMGICs>GICs
• Ease of Handling
PAMCRs>RMGICs>GICs
• Polishability and Esthetics
PAMCRs>RMGICs>GICs

Condensable / Self hardening GIC
• These are basically, purely chemically activated RMGIC
with no light activation at all.
• Developed mainly for luting purposes, they contain
monomers and chemical initiatiors such a the benzoyl
peroxide and t- amines to allow self polymerization.
• It is used mainly in paediatric dentistry for cementation of
stainless steel crowns,space maintainers, bands and
brackets

• According to j Leirskar et al 2001, the high viscosity
occurs to the material by adding poly acrylic acid to the
powder and finer grain size distribution.
Advantages over conventional GIC’s
( A Castro & R F Feigal,2001)
• Packable + Condensable
• Easy placement
• Non sticky
• Rapid finishing can be carried out
• Improved wear resistance
• Solubility in oral fluids is very low

Indications
• As a final restorative material in class I and Class II
primary teeth
• Geriatric restorative material for class I,II,III,IV cavities
and cervical erosion
• Final restorative material in permanent teeth in non stress
bearing areas
• Intermediate restorative material in class I and class II
cavities
• Sandwich restoration
• Core build up material
• Fissure sealing material for permanent teeth

Ketac Molar Aplicap GCFuji IX Capsule

• A hybrid product with a composition between
that of calcium aluminate and GIC, designed for
luting fixed prostheses.
• The calcium aluminate component is made by
sintering a mixture of high-purity Al2O3 and CaO
(approximately 1 : 1 molar ratio) to create
monocalcium aluminate.

POWDER
• calcium aluminate
• polyacrylic acid
• tartaric acid
• Strontium fluoroalumino-
glass
• strontium fluoride
LIQUID
• 99.6% water
• 0.4% additives for
controlling setting.
151

• The calcium aluminate contributes to a basic pH during
curing, reduction in microleakage, excellent
biocompatibility, and long-term stability and strength.

• Composite resins - compound of two or more distinctly
different materials with properties that are superior to
individual constituents
• Cements based on resin composites
– Class I – self cured materials
– Class 2 – Light cured
– Class 3 - Dual cure
• Composition and chemistry :-
– Resin matrix , inorganic filler and organosilanes
– DBA is needed to promote adhesion of resin cements
to dentin
– Adhesive monomer in bonding agent–
Hydroyethylmethacrylate,4-Methacryloxyethyl
anhydride , carboxylic acids

• Synthetic resins are available since 1952 for
cementation
• In 1970 composite resin was introduced as crown and
bridge material
• Since 1986 resin cements have gained popularity by
usage in resin bonded bridges and aesthetic restoration.

Composition:
 Powder /liquid or two paste form.
 Resin matrix / binder– Bis GMA / urethane
dimethacrylate, triethylene glycol dimethacrylate
 Fillers – quartz ,colloidal silica /metal oxides
 Coupling agents – organosilanes
 Also contains – Hydroquinone: prevents premature
polymerisation,
 Opacifiers: Ti dioxide ,Al oxide
 Colour pigments to match the tooth colour

Properties
• Biocompatibility – pulp irritation due to diffusion of
uncured composites or monomers into dentinal tubules
and cause long term pulp inflamation.
• Microleakage – due to polymerisation shrinkage.
• Solubility – less soluble in oral fluids

Mechanical properties
• Compressive strength : 194 – 200 MPa.
• Tensile strength –15 mpa
• Film thickness - > 25 microns
• Removal of excess – moderately easy
• Retention – good, micromechanical bonding

ADVANTAGES:
Low solubility
Good retention
Strength
Good aesthetics
Useful in ceramic veneers and inlay
DISADVANTAGES:
More film thickness
Microleakage due to polymerisation
shrinkage
Pulp irritation
Cost
159

• Ultra Bond
• Insure – Cosmodent
• Choice – Bisco
• Dicor cement system – Dentsply

Water sorption of resin luting agents. C&B-Metabond unfilled resin and resin ionomers
have increased water sorption compared with filled resins tested. (From Kerby RE, et al.
J Dent Res 1995;74:243; and Knobloch L, et al. J Dent Res 1996;75:372.)

These are new generations of adhesive bonding agents
which are been used extensively in dentistry now.
• Since composite resins were very viscous they were not
flowing well into the dentinal tubules of etched surface ,
these adhesive resins flowed well into the irregularities
and bonded well to restoration and tooth surface
• Bonding is achieved with organophosphonates HEMA
(hydroxyl ethyl methacrylate) or 4-META (4-
methacryloxy ethyl trimellitic anhydride)
• The phosphate end of the phosphonate reacts with
calcium of the tooth or with a metal oxide.

• C & B Metabond
• All bond 2
• Panavia

Properties
• Biocompatibility – pulp irritation is present
• Microleakage - very low
• Solubility – very low
• Working time - .5 – 5 min
• Setting time – 1 – 15 min
• Compressive strength – 179 – 255 mpa
• Tensile strength – 30 – 45 mpa
• Film thickness – >25 microns
• Removal of excess – difficult
• Retention – very high

Bonding of esthetic restorations
– Dual cured resin – ideal for ceramic restorations
,composite inlays
– Light cured cements -bonding thin ceramic veneers ,
resin bonded prosthesis
– Light cure more color stable
• Composition
– Microfilled /hybrid composite –> BIS-GMA or
urethane dimethacrylate resins
– Silica or glass fillers – 20 to 70 %

• Dual cured cement – base- catalyst forms
• Light cured composite - photointiated – in presence of
camphoroquinone – amine system
Manipulation
• Bonding is achieved by performing the following steps:
1. Etching fitting surface of ceramic with hydrofluoric
acid
2. Apply silane coupling agent to ceramic
3. Etch enamel with phosphoric acid
4. Applying a resin bonding agent to etched
enamel and silane
5. Seating the restoration with a composite resin
luting agent

Pre -treatment of oxide ceramics
& Metal & Composites

Total-Etch or Selective-Enamel-
Etch Technique
Selective enamel-etch/Total-etch

MaryLand and Inlay / onlay
Bridge

Advantage
Adhesive to tooth structure
Very high retention
Low solubility in oral fluids
Aesthetic
High Strength
Disadvantage
Pulp irritation
Post insertion sensitivity
Cost
Technique sensitive
178

Procedure
5. Acid etch enamel; 37% phosphoric acid for 20 seconds. Rinse thoroughly and dry
4. Etch and silanate restorations
Clean restorations thoroughly in water . Use acetone if luting resin was used to verify
the shade at try-in. Dry the restorations.
Try in restoration with glycerin or a try-in paste
Clean teeth with pumice and water. Isolate with rubber dam.

10. Use dental tape to remove resin flash from interproximal margins of inlays and
onlays before curing these areas.
9. Hold restoration in place while light-curing the resin.
8. Position restoration gently, removing excess luting agent
7. Apply composite resin luting agent to restoration
6. Apply a thin layer of bonding resin to the preparation. Do not polymerize this layer,
because it might interfere with complete seating.

A, Panavia resin cement. B, Measured powder and liquid spatulated for 60 to 90
seconds. mix becomes more creamy as it is mixed. The cement sets if oxygen is
excluded, so it should not be piled up. Instead, it should be spread out over a large
surface area. C, Apply a thin coat of cement, seat restoration, and remove excess
cement. D, cement is coated with oxygen-inhibiting gel to promote polymerization

Resin-metal bonding
• Bondable surface roughened by electrochemical etching
or by grit blasting with 30 to 50 μm alumina particles at
an air pressure of 0.4 to 0.7 MPa.
• Some bonding systems include a metal primer
containing an adhesion promoter.
• Oxide formation on base metal surfaces contributes to
bond strength when resin cement containing 4-META-
based resin is used.

• Bonding improved by use of silica coatings.
• Bond strengths of composites to silica-coated alloys
range from 16 to 22 MPa.

Cement Selection for Implant-
Supported Crowns

Techniques to minimize excess luting
agent in cement-retained implant
restorations
1.place luting agent only on the occlusal half of the intaglio
of the restoration
• This amount will provide sufficient flow to the axial walls
cervically and reduce the amount of excess cement
along the restorative margin
• disadvantage - that incomplete sealing of the restorative
margin

2. Fill the intaglio of the implant restoration with luting
agent, and seat it extraorally on the practice abutment or
implant analog
• Wipe excess cement with a gloved finger or cotton tip
applicator; immediately remove the crown from the
analog, and cement it intraorally
• should be in line with the long axis
• The advantage - more complete flow of cement to the
axial walls and restorative margins of the implant
restoration is achieved

Compressive strength of luting agents. Higher strength values were reported in these
studies with resin cements and glass ionomers than with zinc phosphate or polycarboxylate.
Resin-modified glass ionomer exhibited greater variation than other cements.

Crown retention studies. Effect of luting agent. These 6 in vitro studies evaluated effect of
luting agent on crown retention. Data were normalized as percentage of retention value
with zinc phosphate cement. Adhesive resins had consistently greater retention than zinc
phosphate. Conventional resins and glass ionomers yielded less consistent results.

Resin-to-metal bonding. Effect of luting agent. These 9 in vitro studies evaluated resin luting
agents for metal bonding, namely, for resin-retained restorations. Data were normalized for
Panavia phosphate-based adhesive resin. In most studies it was found to have high retention
values. Carboxylic-based C&B Metabond was found to be superior to Panavia in 1 study and
greatly superior in another. However, it was similar or inferior in 5 studies.

Evaluation of hypersensitivity after the placement of metal
ceramic crowns cemented with two luting agents: Longterm
results of a prospective clinical study
In this study;
 the incidence of postcementation hypersensitivity with
zinc phosphate cement and a self-adhesive resin cement
was not statistically significantly different.
 The practitioner can choose equally between
selfadhesive or conventional luting material when metal
ceramic crowns are cemented definitely.
Carla Kozmacs et al;J Prosthet Dent 2016

A Comparative Study Of Retentive Strengths Of Zinc
Phosphate, Resin Modified Gic And Adhesive Resin
Cement With Stainless Steel Crowns - An In Vitro Study
Shveta Munjal et al: Indian Journal of Dental Sciences. October 2013
Supplementary Issue Issue:4, Vol.:5
The study was conducted to compare the Retentive strengths of
Zinc phosphate, Rely X Luting II (RMGIC) and Rely X ARC (Adhesive
resin cement). When 1day and 7 days results were compared only
zinc phosphate cement had significant decrease in the retentive
strength values. Among the other two cement groups Rely X Luting
II and Rely X ARC showed no significant decrease in the retentive
strength values. ARC can be recommended for cementation of
stainless steel crowns.

A laboratory and clinical evaluation of three dental
luting cements
The loss of material from specimens of three luting
cements was measured after continuous erosion cycling
in the laboratory. The glass ionomer luting cement
showed significantly less material loss than the zinc
polycarboxylate and zinc phosphate luting cements.
P. J. Knibbs And A.W. G. Walls Journal of Oral Rehabilitation,
1989, volume 16, pages 461-413

References
• Phillips’ science of dental materials, 11th ed, Anusavice
• Philips science of dental materials 12th edition
• Contemporary fixed prosthodontics , 4th edition
Rosensteil
• Dental material and its selection ,3rd ed. William J O’
Brien
• Restorative dental materials, 11th ed. Robert G
• Materials used in dentistry , S.Mahalekshmi

Cross references
• Stephen F. Rosenstiel J Prosthet Dent 1998;80:280-301
• Carla Kozmacs et al;J Prosthet Dent 2016
• Shveta Munjal et al: Indian Journal of Dental Sciences.
October 2013 Supplementary Issue Issue:4, Vol.:5
• P. J. Knibbs And A.W. G. Walls Journal of Oral
Rehabilitation, 1989, volume 16, pages 461-413

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