This document provides an overview of dental cements. It begins with definitions of dental cements and discusses their history. It describes ideal cement properties and classifications including based on ingredients/application, bonding mechanism, and setting reaction. Specific cement types are then outlined - silicate, zinc phosphate, zinc polycarboxylate, zinc oxide eugenol, calcium hydroxide, and their compositions, reactions, properties and uses. The document provides a detailed comparison of zinc phosphate and zinc polycarboxylate cements. In summary, it is a comprehensive review of different dental cement types, their characteristics and applications.
4. INTRODUCTION
In last 20 years there has been an explosion of different
types of dental cements that have become available to
practicing dentist ,many of them tailored for specialized
types of restoration. In fact ,there are so many products to
choose from the task ,can become confusing.
Dental cements, in the recent years has become
restricted to those materials which are employed to bond
inlays, crowns, bridges, posts and facings in or on the tooth
and to retain orthodontic bands and retainers, however
secondary applications of these cements include cavity
linings, bases and temporary fillings, endodontic sealer.
5. These different applications make varying
demands on manipulative properties, working
and setting times, and resistance to mechanical
breakdown and dissolution. Thus some materials
are better suited to some application than
others.
Many of these materials are supplied in
powder/liquid form and set by an acid-base
reaction, but this is not universally true.
As yet, there is no ideal dental cement. Each
material must be used on its merits with
knowledge of its limitations.
7. o A substance that hardens to act as
a Base, Liner, Filling material or
Adhesive to Bind Devices and
Prosthesis To Tooth Structure To
Each Other .
(Anusavice)
9. 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
10. Ideal properties of dental cements
Should be strong and hard.
Able to protect pulp
Should be insoluble in saliva & liquids taken in mouth.
Should be dimensionally stable.
Should be adhesive .
Should be non porous .
Should be biocompatible and non irritant.
Co-efficient of thermal expansion should be equal to the
tooth structure.
Should not be affected by thermal changes and
moisture.
Should be easy to manipulate.
11. 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
12. 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
- High strength bases
- Long term provisional restoration
3) Zinc phosphate :
- Retention of- Conventional alloy based restoration
-Orthodontic bands
- High strength bases
- Long term provisional restoration
13. 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
- High strength bases
18. Silicates
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.
19. Powder:
Silica
Alumina
Fluoride compounds
Calcium salts
Fluoride Flux -
To permit proper sintering
of the other ingredients.
Liquid :
Phosphoric acid
Water
Buffer salts
20. Setting Reaction
Powder mixed with liquid
Powder attacked by acid liquid releasing Ca, Al, Fl
ions
Metal ions precipitate as phosphate
cement matrix inclusive of Fl salts
21. Advantages
It exhibit good esthetic qualities .
Anticariogenic property.
Analogues to topical applied fluoride solution.
DisadvantagesDisadvantages
It lacks stability in oral fluids with loss of esthetic qualitiesIt lacks stability in oral fluids with loss of esthetic qualities
Rubber dam is essential for successful silicateRubber dam is essential for successful silicate
restoration.restoration.
Irritant to pulp.Irritant to pulp.
22. Zinc Phosphate cement
Introduced over a
century ago It is the
oldest luting cement.
Longest clinical track
record to compare
with newer systems.
Synonyms `Crown and
Bridge’ and “Zinc
oxyphosphate’
23. ZINC PHOSPHATE CEMENT
COMPOSITION
POWDER
Zinc Oxide - Principle Ingredient
Magnesium Oxide - reduces the temp. of calcification process
2.10% aids in sintering.
Oxides of
Bismuth, Calcium or - Impact a smoothness to freshly mixed
Barium Cement mass.
In large quantities lengthen the S.T
Silicon Dioxide - In active filler
LIQUID
Phosphoric acid - 45-64% Reacts with ZnO
Water - 30 – 55% Increases Rate of reaction
Aluminum - 2.3% Essential to the cement forming reaction –
Zinc - 0.9% Moderates reaction between powder and
Liquid allows adequate working time
24. CLASSIFICATION
(Anusavice 9th
edition )
Type I
-Fine grained for luting
-Film thickness should
be less than 25 um
Type II -
- Medium grained for
luting and filling
- Film thickness
should be more than
40um
25. 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
26. 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.
27. NOTE : Powder liquid reactions ,an accelerated by the
presence of heat (exothermic reaction)
Liquid consists of partially centralized dilute Phosphoric
acid. .
When this liquid is exposed to a humid atmosphere, it will
absorb water. Whereas exposure to dry air tends to result
in a loss of water which will alter the property of cement.
28. 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 210
C.
Effective when multiple castings are to be cemented.
Excess of cement is easy to clean up .
But decrease in compressive strength.
29. SETTING REACTION
Exothermic reaction
Powder & liquid mixed
Phosphoric acid attacks the surface
Release of zinc ions & reaction of Al with phosphoric acid
Al & Zn ions react with phosphoric acid
Zinc alumino phosphate gel
and surrounds with un reacted particle
Thus the set cement is a cored structure consisting primarily of un-
reacted Zinc Oxide particles embedded in a cohesive amorphous matrix
of zinc aluminophosphate.
Water is critical to reaction.
30. Properties
Compressive strength -104 Mpa
Tensile strength -55 Mpa
Modulus of elasticity – 13.7Gpa ( stiff & resistance to
deformity )
Retention is mechanical
At insertion PH at 2 min – 2
at 24 hrs – 5.5
Damage to pulp occurs during first few hrs of insertion.
WT
MT
ST 5 min5 min
2.5 -8 min2.5 -8 min
1.5 -2 min1.5 -2 min
31. Advantages
Most popular for cast restorations
Adequate strength
Reasonable working time
Excess material can be easily removed
Acceptable effect over the dental pulp
Manipulation less critical than other cements.
Disadvantages
Pulp irritation
Lack of antibacterial action
Brittleness
Lack of adhesion
Solubility in acid fluids
32. Variations in Zinc Phosphate Cement
Fluoridated cement:
o Small % of stannous fluoride.
o Lower strength & higher solubility than zinc phosphate.
o Fluoride release continues over long period & uptake.
reduces enamel solubility ,increases harness.
o This activity should reduce the incidence of enamel
decalcification under orthodontic bands.
o Used in orthodontic band cementation.
Copper/Silver cement:
o Consists of proportion of red or black cuprous oxide or
copper salts or silver salts to zinc oxide powder.
o Liquid same as conventional.
o Used in past due to germicidal action.
o Were discontinued due to staining of teeth.
33. Silicophosphate cement :
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 for pulp
irritation.
Used for cementation orthodontic bands & restoring non vital teeth
34. Zinc Polycarboxylate Cement
It is the 1st
adhesive material
developed in dentistry.
Advantages over the
traditional ZnPO4
• Compatibility with pulpal
tissue
• Adhesion to tooth
structure.
35. ZINC POLYCARBOXYLATE CEMENT
POWDER: (Same as zinc phosphate)
-Zinc oxide – Main ingredient
- Stannous oxide –Replaces magnesium oxide
- Silica, Alumina or Bismuth - Filler
- Stannous fluoride – 4.5% improves the
manipulation,
characteristics, strength.
-Sodium fluoride - 1% Anticariogenic property
LIQUID
- Aqueous solution of Polyacrylic acid
- Co-polymer of acrylic acid
- Other carboxylic acid ( itconic acid) – stabilizes the liquid
36. ZINC POLYCARBOXYLATE
MANIPULATION:-
Mixed at a P/L of 1.5 :1
The consistency is creamy compared with that of zinc phosphate
cements.
The correct consistency is found in a mix that is viscous but that
will flow back under its own weight when drawn up with spatula.
Dispensing of the liquid should be done immediately before
mixing to prevent evaporation of water and subsequent
thickening.
The mixed cement should be used only till appears glossy on the
surface. Once the surface becomes dull, the cement develops
stringiness and the film thickness becomes too great to seat a
casting completely.
37. Non absorptive surface, such as glass slab or treated
paper, will keep all the liquid available for the
reaction and facilitate spatulation.
Polyacrylate cements should be mixed within 30-60
sec, with half to all of the powder incorporated at
once to provide the max thickness.
The strength of the mixed cement is not compromised
by this technique.
38. Setting Reaction
Surface dissolution of particles by acid
Release of Zn, Mg ,Sn ions
Bind to polymer chain by OH group
Reacts with carboxylic group
Cross linking of polymer chain
Amorphous gel particle with unreacted particle dispersed
39. Properties
Compressive strength – 55 -67 Mpa
Tensile strength –slightly higher than ZnPO4
Modulus of elasticity -2.4 – 4.4 Gpa (less
stiffer
& less brittle than ZnPo4 )
Low soluble in oral fluids than ZnPO4
Excellent biocompatibility with pulp
2.5 min2.5 minWTST
MT
30-60 sec
6 -9 min6 -9 min
40. Advantages :
Low level of irritation
Good adhesion to tooth substances & alloys.
Good strength ,solubility & film thickness
compare to zinc phosphate.
Disadvantage
Need for accurate proportion, more critical
manipulation
Lower compressive strength & greater visco-
elasticity than zinc phosphate.
Short working time & need clean surface to use
adhesion potential (technique sensitive).
41. Zinc Oxide Eugenol
Extensively used in dentistry
since 1890’s .
Least irritant of all the dental
materials.
Poor strength when compared
to zinc phosphate.
It has sedative effect on
exposed dentin.
42. ZINC OXIDE EUGENOL
ZnOZnO PrincipalPrincipal
IngredientIngredient
White rosinWhite rosin BrittlenessBrittleness
of setof set
cementcement
Zn acetateZn acetate AcceleratorAccelerator
strength –strength –
up to 1%up to 1%
MgOMgO ModifierModifier
Zn stearateZn stearate PlasticizerPlasticizer
EugenolEugenol Reacts with ZnOReacts with ZnO
Olive OilOlive Oil Plasticizer (85%Plasticizer (85%
Eugenol)Eugenol)
WaterWater InitiatorInitiator
AceticAcetic
acid/alcacid/alc
oholohol
To accelerateTo accelerate
setting – about 1%setting – about 1%
POWDER LIQUID
43. CLASSIFICATION (ADA Sp. No 30)
Type IType I Used for Temporary cementationUsed for Temporary cementation
Type IIType II Used for Long Term cementation ofUsed for Long Term cementation of
fixed prosthesisfixed prosthesis
Type IIIType III Temporary Filling/ ThermalTemporary Filling/ Thermal
insulating baseinsulating base
Type IVType IV Intermediate Restorations andIntermediate Restorations and
Cavity linersCavity liners
44. ZINC OXIDE EUGENOL CEMENT
MANIPULATION
Temporary cements (Type I) & Liners ( Type IV )
A typically two paste systems.
Dispense equal lengths of the accelerators and base
pastes on a paper pad / glass slab
Continue mixing until a uniform colour is achieved.
Long term Zinc oxide Eugenol Cements (Type – II)
A powder & liquid system.
Shake the powder bottle gently, then dispense the
powder with the supplied scoop and the liquid with a
dropper.
Mix on a glass slab or treated paper pad with a metal
spatula. Incorporate the powder into the liquid all at
once and mix for 30 sec.
Coat the patient’s lips and adjacent teeth with petroleum
gel before application of the cement. Oil of orange is a
solvent useful in removing set cement.
45. ZINC OXIDE EUGENOL
SETTING REACTION
zinc dioxide hydrolysis
zinc hydroxide
eugenol
zinc eugenol
Water is needed to initiate the reaction and it is also a by-
product of the reaction. So the reaction proceeds more
rapidly in a humid environment.
The setting reaction is also accelerated by the presence of
zinc chelate dehydrate.
Acetic acid is a more active catalyst for the setting reaction
than is water because it increases the formation rate of zinc
hydroxide. High atmospheric temperature also accelerates.
46. Advantages:
Minimal pulp reaction.
Good sealing properties
Strength adequate for lining material & luting single
restoration & retainers, with good retention form.
Disadvantages:
Hydrolytic breakdown under exposure to oral fluids
Inflammatory reaction in soft tissue
potential allergic response
Minimal mechanical properties for luting
May soften & discolor
49. 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.
WTST
MT
5 min7-9 min
2 min
51. 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.
52. ADVANTAGES
• Easy manipulation
• Long working time
• Good flow characteristics & 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
54. 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
55. Setting reaction initiated by saliva & water.
Better sealing into cavity walls due to hydroscopic properties.
Minimum thickness of atleast 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.
56. Calcium Hydroxide
INTRODUCTION
It has multipurpose use
though not used as
permanent restorative
material
Ca(OH)2 is a white
odorless powder
Mixed with water or saline
to a form a paste.
It is strongly alkaline with
a PH of 12.5
It is classified as an
astringent in
Pharmacology.
57. HISTORY
In 1936 Hermann introduced Ca(OH)2
to promote healing in many clinical
situations
The introduction of this material in the
US was by Teuscher and Zander in
1938.
Successful pulpal healing using
Ca(OH)2 is between 1934 & 1941.
58. CHARACTERISTICS OF
Ca(OH)2
Molecular weight of 74.08.
Radiolucent
Specific Gravity of 2.34
PH 12.5 at 25 C
Very slightly soluble in water,
soluble in glycerin syrup and acids.
59. MECHANISM OF ACTION
High alkaline PH(11-13) Causes neutralization
of acids produced by microorganisms.
Antibacterial effect due to high PH.
Seals the dentinal tubules offering dentin
protection.
Induces reparative dentin below existing
dentin.
Biocompatibility & calcific barrier enabling to
maintain pulp vitality.
Ca(OH)2 maintains a local state of alkaline by
that is necessary for bone/dentin formation .
60. On Vital dentin
Considerably reduces the permeability of exposed dentin
for penetration of bacterial components towards the pulp.
This may be due to
Coagulation of proteins in dentinal
tubules
Due to secondary dentin formation
It has an antibacterial effect
61. On Carious Dentin
Ca(OH)2 has a strong antibacterial effect on the
contaminated soft carious dentin.
ON EXPOSED PULP
Low grade irritation due to coagulative necrosis
caused by Ca(OH)2 leading to hard tissue
differentiation in the pulp to calcific barrier
formation.
62. DIFFERENT FORMS OF Ca(OH)2 AVAILABLE
1) DRY POWDER
Dry powder of Ca(OH)2 medicinal grade. Free from
impurities and contaminants is available. The powder could be
supplied as such or mixed to a paste with either distilled water
or normal saline. Mixing with water or ortho ethoxy benzoic
acid is avoided as the reaction is too fast for convenient
clinical use.
2) LIQUIDS
They are supplied in bottles. Resinous solution of Ca(OH)2
are used as liners. The combination or resin film with alkaline
Ca(OH)2 provides a protective film having better physical
integrity as well as chemical neutralizing capacity for acids.
63. 3) NON – SETTING PASTES
They are supplied in Jar’s or inject able single paste
system. In these materials, calcium hydroxide is not
reacting with other ingredients of the paste. The other
ingredients are only carriers and the availability of
free Ca and OH ions from the preparation will be
more.
65. 2. Visible light activated Ca(OH)2 – Single paste
system.
CaOH
BaSO4
UDMA Resin
Camphorquinous
5) SLOW SETTING Ca(OH)2 Pastes.
Root Canal Sealer materials
Ca(OH)2 can be used as a sealer to coat the Would of the pulp
space and form a hermetic seal
Ex – Calcibiotic
Root Canal Sealer paste (CRCS Paste)
Containing – ZOE, Ca(OH)2
66. VEHICLES
When CaOH2 powder is mixed with a suitable vehicle a paste is
formed.
The vehicles play a major role in the over all process because it
determines the velocity of ionic dissociation causing the paste to
re-establish and restore at various rates by the peri apical tissues
within the root canal.
Types of Vehicles are used
Aqueous Vehicles – Water
Saline
LA solution
Viscous Vehicles - Glycerine
Polyethyl glycol
Oily vehicles - Olive Oil
Fatty acids.
Eugenol.
67. Direct PulpDirect Pulp CappingCapping
Indirect Pulp CappingIndirect Pulp Capping
BaseBase
PulpotomyPulpotomy
LinerLiner
Root canal sealerRoot canal sealer
Prevention & treatment of ResorptionPrevention & treatment of Resorption
Repair in perforationRepair in perforation
Intra Canal MedicamentIntra Canal Medicament
Horizontal #Horizontal #
Root fractureRoot fracture
ApexificationApexification
CALCIUM HYDROXIDECALCIUM HYDROXIDECalcium Hydroxide
69. Summary
Zinc phosphate cement has long served as the universal luting
cement. Its advantages includes good handling
characteristics and a proven longevity in the oral cavity when
it is used for cementation of well designed and well fitting
restorations.
Its disadvantages include pulp irritation, lack of adhesiveness
to tooth structure, and lack of anticariogenic properties.
ZnPO4 is not suitable when the mechanical retention poor or
when the aesthetic demand is high.
The main advantage of improved Zinc Oxide Eugenol cement
is their biocompatibility. The physical and mechanical
properties and the handling characteristics generally inferior
to those of other long term luting cements.
70. The properties of zinc Polycaroxylate cement are good compared
with those of ZnPO4. The outstanding characteristics are their
blandness to the pulp and formation of an adhesive bond to tooth
structure.
Disadvantages include the short WT, SF and limited capabiling for
fluoride release. Their short W.T limits their used to single units or
three unit fixed partial dentures (bridges). These cements have
decreased in popularity, but they are still often used for patients
who have reported a history of postoperative sensitivity.
Calcium hydroxide is not a restorative material by itself many a
time , but forms a part of restoration. Its fascinating osteogenic &
dentinogenic potential have elevated its status as unique material
used in dentistry.
71. REFERENCES
Theodore M. Roberson: Sturdevant’s Art and Science of Operative
Dentistry 4th
& 5th
edition.
Skinners
Kennith J Anusavice: Phillips’ Science of Dental Materials 11th
edition & 9th
edition.
S Mahalaxmi : Materials used in dentistry,2013.
Robert G. Craig and John. M: Restorative Dental Materials 11th
edition & 12th
edition.
Joyre Reese , Thomas Valege :Restorative Dental Materials :An
Overview, 2nd
edition
Williams O'Brien. 2002 & Richard van Noort
E C Combe 6th
edition.
Editor's Notes
The earliest dental cement composition was zinc oxide and eugenol (ZOE). [CLICK] Cast alloys were actually used in dentistry as early as 1850 by grinding up gold coins as a source of material. Their composition is roughly that of a Au-Cu Type III composition used today. Impressions were accomplished with plaster. Once set the impression was fractured carefully along occlusal and facial surfaces so that it could be re-assemble by gluing and poured to generate a working cast. Dies were waxed and invested in plaster. The investment mold was cast by melting gold in a coal or charcoal furnace, pouring it into the mold, and using steam, and centrifugal force from a sling to drive the molten alloy into the detailed portions of the mold space. The finished restoration was then cemented with ZOE. While cemented alloys were not in common use, the indirect fabrication process could be accomplished at least in a primitive way.
[CLICK] Experiments with early versions of zinc phosphate cement occurred at the National Bureau of Standards in the 1900-1920 range. [CLICK] Silicate cements arose during the 1930s as restorative materials but with some application as luting materials. [CLICK] Polycarboxylate cement was invented by Dr. Dennis Smith in 1960. [CLICK] Glass ionomer cements for restorations and luting were introduced into dentistry in 1972 but Alan D. Wilson (who contributed earlier to silicate cement research) as a hybrid cement using silicate cement powder and polycarboxylate cement liquid. [CLICK] Composite cement was introduced about 1980 but not used very often until later. [CLICK] Resin modified glass ionomers and [CLICK] compomers evolved from glass ionomer after 1990. [CLICK] Only some of these appear in a contemporary dental practice and that number has focused on just a couple in recent times.