Dental cements_1670373000.pdf

Dental cement

1. DENTAL CEMENTS
Dr. Puja Lamichhane
MDS
Dept. of Cons and Endo

2. CONTENTS
Introduction
Classification
General properties
Uses
Zinc phosphate cement
Zinc polycarboxylate cement
Zinc oxide eugenol cement
Silicate cement
Silicophosphate cement
Resin cements
Compomers
References
Questions

3. INTRODUCTION
Cement is a material which bonds other substances together
In dentistry, the term ‘cement’ has been applied traditionally to powder-liquid
materials; which are mixed to a paste consistency and set to a hard mass
and used clinically to restore teeth either alone or with other materials (mixed
to a secondary consistency) and to attach pre-formed restorations or
appliances in a fixed position within the mold
Materials that set intra-orally and that are commonly used to join a tooth
and a prosthesis

4. CLASSIFICATION
CLASSIFIED BY INGREDIENTS AND APPLICATIONS (ISO classification):
I.Water-based cements
II.Resin-based cements
III.Oil-based cements

5. WATER BASED CEMENTS
Glass and resin modified
Glass Ionomer Cements
Zinc Polyacrylate /
Polycarboxylate Cement
Zinc Phosphate Cement
Class V restorations Retention of alloy restorationsRetention of conventional
restorations
Retention of conventional
alloy-based restorations
Retention of orthodontic
bands
Retention of orthodontic
bands
Retention of alumina or
zirconia-based all-ceramic
restorations
Retention of pediatric
stainless steel crowns
High-strength bases
Retention of orthodontic
bands
High-strength bases Long-term provisional
restorations
High-strength bases Long-term provisional
restorations
Long-term provisional
restorations

7. RESIN-BASED CEMENTS
Composites and Adhesive Resins Compomers
Bonded conventional alloy-based restorationsBonded conventional alloy-based restorations
Bonded ceramic crowns, bridges, veneers,
inlays and onlays
Retention of alumina-or zirconia-based all-
ceramic restorations
Bonded laboratory composite crowns, bridges,
veneers, inlays and onlays
Retention of orthodontic brackets
Retention of provisional restorations High strength bases
Retention of orthodontic brackets
Bonded posts and cores

8. Veneers Orthodontic brackets

9. Post and core

10. OIL BASED CEMENTS
Zinc Oxide –Eugenol Cements Noneugenol–Zinc Oxide Cements
High-strength bases Provisional restorations (esp. for teeth that will
have bonded permanent restorations)
Provisional restorations Root canal sealers
Root canal sealers Gingival tissue packs
Gingival tissue packs Surgical dressings
Surgical dressings

11. ACCORDING TO SETTING REACTION
I.Acid-base reaction cements
II.Polymerizing cements
III.Dual cure cements
IV.Tricure cements

12. ACID BASE REACTION CEMENTS
Powder and liquid
Powder:base
Liquid: acid
P+L = acid base reaction
viscous paste
hardens to a solid mass

13. POLYMERIZING CEMENTS
Set by polymerizing reaction
Light activated / chemically activated
Eg.: resin cements

14. DUAL AND TRICURE CEMENTS
Dual cure cements: Sets by acid base and any of the polymerization
reactions (light / chemical activation)
Tricure cements: Uses all 3 mechanisms (acid-base + light activation +
chemical cure) for hardening

15. ACCORDING TO APPLICATION (ISO 9917 -
1:2007)
I.Luting
II.Bases or lining
III.Restoration

16. GENERAL PROPERTIES OF CEMENTS
1.Film thickness and consistency
2.Viscosity
3.Setting time
4.Strength
5.Solubility
6.Modulus of elasticity (MOE)
7.Biological properties
8.Fluoride release

17. FILM THICKNESS AND CONSISTENCY
•Film thickness determines the adaptation and retention of restoration to the
tooth
•Maximum thickness is 25 μm
•The heavier the consistency, greater the thickness
The ultimate film thickness that a well-mixed, non-granular cement attains
depends on:
Particle size of the powder
Concentration of the powder in the liquid
Viscosity of the liquid and
Consistency of the cement

18. FILM THICKNESS AND CONSISTENCY
•Consistency of the cement used in the cementation of a casting is critical
•In powder-liquid type of cement, an increased amount of powder
incorporated in liquidwill increase the consistency of the cement mass

19. VISCOSITY
•The consistency of cements can be quantified by measuring viscosity
•Increase in temperature and time have both been shown to increase the
viscosity of some cements
•Delay in cementation can result in larger values of film thickness and
insufficient seating of the restoration
•For resin cements, viscosity can vary widely and some products come with
a choice of different viscosities

20. SETTING TIME
Of equal importance to the viscosity of the cement is its setting time
A sufficient time must be available after mixing:
to seat and finally adapt the margins of a restoration
to seat and adjust a series of orthodontic bands
or to properly contour a base of provisional restoration
Adequate working time is expressed by net setting time, as determined by
ANSI (American national standards institute) / ADA specification no. 96 and
based on a luting consistency, in between 2.5 and 8 mins. at a body temp. of
37°C

22. SETTING TIME
Net setting time allows final finishing procedures associated with the
restoration
The 1
st
60-90 seconds are consumed by mixing the cement
So, the net setting time is the time elapsed between the end of mixing and
time of setting

23. STRENGTH
ANSI / ADA Specification No. 96 (ISO 9917) stipulates that the standard
luting consistency of a dental cement must exhibit a minimum 24 hour
compressive strength of 70 Mpa

24. SOLUBILITY
Solubility in water and oral fluids is also an important consideration in
cement properties
Water-based cements are more soluble than oil-based
ANSI / ADA Specification No. 96 allows a maximum rate of acid erosion,
which is variable for different types of cements, when a cement is subjected
to lactic acid erosion by an impinging jet technique

26. MODULUS OF ELASTICITY
•This is the measure of the stiffness of a cement
•Cements under ceramic crowns should have sufficient stiffness to withstand
masticatory loads
•A low MOE can result in flexing of the restoration resulting in fracture

27. FLUORIDE RELEASE
•Most of the cements contain Fluoride
•Gradually released over a period of time to impart adjacent tooth structure
with caries resistance
Eg.: Glass Ionomer cement

29. USES OF CEMENTS
CEMENT FUNCTION
Zinc phosphate, Zinc silicophosphate, EBA
(ethoxy benzoic acid) cement, Zinc
polycarboxylate, Glass ionomer, Resin cement
Final cementation
Zinc oxide eugenol, Non-eugenol Zinc oxide Temporary cementation
Zinc phosphate, reinforced Zinc oxide eugenol,
Zinc polycarboxylate, Glass ionomer, Zinc oxide
eugenol, Calcium hydroxide
Bases
Glass ionomer, Compomer, metal modified GICLong-term restorations
Zinc oxide eugenol, reinforced Zinc oxide
eugenol, Zinc polycarboxylate, Glass ionomer
Temporary and intermediate restorations
Calcium hydroxide Pulp therapy
Zinc oxide eugenol Obtundent (pain relief)
Calcium hydroxide in a suspension Liners
Zinc oxide eugenol, Zinc polycarboxylate Root canal sealer

30. PART II

31. ZINC PHOSPHATE CEMENT

32. CONTENTS
•Introduction
•Classification
•Composition
•Setting reaction
•Manipulation
•Properties
•Precautions
•Advantages and disadvantages
•Applications
•Modifications

33. ZINC PHOSPHATE CEMENT
Traditional crown and bridge cement
Uses:
–Permanent cement for indirect restorations including inlays, onlays, crowns,
andbridges
–Orthodonticcement
–High-strengthbase

34. CLASSIFICATION
According to A.D.A no. 8
Type I: fine grain cement
Has finer particles capable of forming film thickness of 25 μor less: cementation of precision fitting
castings
Type II: medium grain cement
Maximum allowable thickness is 40 μ(micron)
Cementation of orthodontic bands / thermal insulating bases

35. AVAILABLE AS
•Powder and Liquidform
•Capsules for pre-proportioned Powder andLiquid

36. COMPOSITION
POWDER:
INGREDIENTS % FUNCTIONS
1.ZnO (zinc oxide) 90.2%Reactive ingredient
2.MgO (magnesium oxide) 8.2%To reduce the temp. of calcination process
3.SiO
2 (silicon dioxide) 1.4%Inert filler / reinforcing filler
4.Bi
2O
3(bismuth trioxide) 0.1%Smoothness impartment to the freshly mixed cement mass and
in larger amount it may also lengthen the setting time
5.BaO / BaSO
4/ CaO 0.1%Modifier, radio-opacity
6.Color pigments. Eg.: CuO
(copper oxide), MnO
2 (
manganese dioxide)
Traces CuO, MnO
2 and platinum black produce shades of grey
Bismuth oxides or certain chromates: yellow
Iron oxide: brown or green

37. COMPOSITION
LIQUID:
INGREDIENTS % FUNCTIONS
1.Orthophosphoric acid38.2%Reactive ingredient
2.Zn
3(PO
4)
2(zinc
phosphate) / AlPO
4
(aluminium
phosphate)
16.2%a.Stabilize the pH of acid against the effects in changes of concentration
due to evaporation or condensation of water
b.Reduce its reactivity by partial neutralization of phosphoric acid
•This produces smooth, non-granular workable cement during mixing
3.Pure zinc 7.1% Moderator of the reaction between powder and liquid allowing adequate
working time and permitting sufficient quantity of powder to be added for
optimum properties
4.Pure alumina 2.5% It is essential to the cement forming reaction and assist in the formation of
an amorphous reaction product (zinc alumino phosphate) which forms
stronger cement
5.Water Controls the ionization of liquid and influences the rate of reaction, i.e. the
presence of an additional water shortens the setting time whereas
insufficient amount of water results in a prolonged setting time

38. SETTING REACTION
•ZnO+ aluminophosphoric acid Zinc alumino phosphate gel + heat
(powder) (liquid) (reaction matrix)
•When mixed, phosphoric acid dissolves the zinc oxide, which reacts with the
aluminum phosphate and forms zinc aluminophosphate gel on the remaining
undissolvedzinc oxideparticles.
•Loss of water from the liquid lengthens the setting reaction and viseversa.
•Mixing Time : 1.5 –2mins.
•SettingTime: 2.5 –8mins.
•ExothermicReaction

39. SETTING REACTION
Note:
•The liquid controls the pH and the rate of the liquid-powder (acid-base)
reaction.
•Finer the particle size, faster the cementsets.

40. MANUFACTURE
•The ingredients are mixed and heated at temperature between 1000°C-1400°C.
(SINTERING)
•After this, cake formed is cooledquickly.
•This causes material to crack which helps in grinding of the fine material to a fine
powder. (FRITTING)

41. MANIPULATION
1.Stainless steel spatula and clean cool glass slab are use for
mixing.

42. 2.MixingTime:-1min. 15sec.
3.P/L Ratio:-1.4gm/0.5ml.
4.The powder is added in smallincrements.

43. 5. Mixing is done with stainless steel spatula using brisk circularmotion.
6.Each incrementsis mixed for15-20sec.

44. 7.A large area is covered during mixing in order to dissipate
the exothermicheat.

45. MANIPULATION

46. FROZEN SLAB TECHNIQUE
In this technique, a glass slab is cooled in a refrigerator at 6°C or a freezer
at -10°C
No attempt is made to prevent moisture from condensing on a slab when it
is brought at room conditions
A mix of cement is made on the frozen / cold slab by adding the powder
until correct consistency is reached
The amount of powder incorporated with this technique is 50-70% more
than with the normal procedures

47. CONTROL OF WORKING TIME
The length of the working time may be varied to some degree to fit the clinical
situation. For eg.A fixed dental prosthetics with multiple crowns require more
working time for cementation. Four techniques can extend the working time of ZP
cement:-
1.P/L ratio can be reduced to produce a thinner mixture. This however, reduces
initial pH and adversely affect theproperties.
2.Smaller portions of powder should be mixed for the first few increments. This
reduces the acidity of the liquid and retards the rate ofreaction.
3.Prolong the spatulation of the last increment of the powder. This destroys the
matrix formed, thus extra time is needed to rebuild the bulk of the matrix. This
is however, not a preffered method for prolonging the workingtime.

48. CONTD.. CONTROL OF WORKINGTIME
4. A cooler mixing temperature retards the chemical reaction between powder and the
liquid, thereby delay formation ofmatrix.
However, the temperature of the slab should be above the dewpoint,
otherwise water condenses, dilutes the liquid and reduces the compressive
and tensile strength of thecement.
This is the most feasible method of extending the working time of zinc
phosphatecement.

49. PROPERTIES OF ZINCPHOSPHATE
•Compressive Strength –104MPa
•Tensile Strength –5.5MPa
•Modulus of Elasticity –13GPa
•Solubility –0.06% (relativelylow)
•Thermal Properties –Good
•Adhesive Properties –No bond formation
•Biological Properties –starting pH: 3.5, at the time of
cementation, pH is: 2 and after 24hrs, pH is5.5
•Optical Properties -Opaque

50. PRECAUTIONS
1.The liquid bottle should be kept closed when not in use to prevent
changes in water content.
polyethylene squeeze bottles don’t require removal of a dropper and thus eliminates the
tendency for gain or loss of water from liquid
2.Liquid should be dispensed onto the slab until mixing is to be initiated
because water will be lost by evaporation
3.A bottle which has become cloudy due to the loss of water should be
discarded.
Such a condition is the result of precipitation of buffering salts
Last 1/5
th
portion of the liquid should be discarded to ensure consistent mix

51. ZINCPHOSPHATE
ADVANTAGES
•Good compressivestrength
•Can be used in regions of high
masticatory stress or long span
prosthesis.
•Good thermal insulationability
•Does not dissolve in oralfluids
•Adequate filmthickness
•Reasonable workingtime
DISADVANTAGES
•No chemicaladhesion
•Pulpirritation
•Poor aesthetics
•Low tensilestrength

52. APPLICATIONS OF ZINCPHOSPHATE
•Luting forrestorations
•High strengthbases
•Temporaryrestoration
•Luting for orthodontic bands andbrackets

53. MODIFICATIONS OF ZINC PHOSPHATE
CEMENT
I.Hydro Phosphate Cement
II.Copper Cement
III.Silver Cement
IV.Fluoride Cement

54. HYDRO PHOSPHATE CEMENT

55. HYDRO PHOSPHATE CEMENT
•It is an innervation in the compounding of Zinc phosphate cement in the mixing of
dehydrated dihydrogen phosphates, zinc, calcium and other metals
As well as the oxides of these metals with water
•The properties like compressive strength, film thickness, solubility and disintegration
are somewhat inferior to that of Zinc Phosphate cement
•The acidity is similar to that of conventional Zinc Phosphate cement
•Used for luting and bases

56. COPPER CEMENT

57. COPPER CEMENT
Copper oxides are sometimes added to the powder of Zinc Phosphate
cement to increase their antiseptic properties
They can be combined directly to powder form with phosphoric acid to
produce cement
USES:
Temporary restoration particularly in pedodontics
Seldom used currently because their clinical behavior doesn’t seem to be superior to any
other temporary restoration and their toxic reaction to the pulp is generally recognized

58. COPPER CEMENT
Copper cements have been classified according to the percentage of
copper oxide that is used to replace zinc oxide
a)Type I: those in which up to 25% of copper oxide has been added to
replace zinc oxide (ZnO)
b)Type II: those in which copper oxide is present as an amount of 2-5%

59. SILVER CEMENT

60. SILVER CEMENT
Generally contain few percentage of salts such as AgPO
4(silver phosphate)
Silver salts darkened to silver sulfide on exposure in the mouth, hence used
only in posterior teeth

61. FLUORIDE CEMENT

62. FLUORIDE CEMENT
Some Zinc Phosphate cements that contain a few percentage of stannous
or other fluorides are obtainable that may be suitable for orthodontic
cementation
They have a lower strength and higher solubility than Zinc Phosphate owing
to the dissolution of fluoride containing material
Fluoride uptake by enamel of some cements results in reduced enamel
solubility

63. PART III

64. ZINC POLYCARBOXYLATE
CEMENT

65. CONTENTS
•Introduction
•Uses
•Composition
•Setting reaction
•Properties
•Manipulation
•Advantages
•Disadvantages

66. ZINC POLYCARBOXYLATE CEMENT
ADA No. 61
•First dental cement to exhibit chemical bonding to
teeth.
•Not used for permanent restorative purposes

67. USES
–Permanentcementforcrowns,bridges,inlays,andonlays
–Orthodontic cementation
–High-strengthbase
–Temporary restorative material

68. COMPOSITION
Powder:
Ingredients %Functions
1.Zinc oxide (ZnO)
80%
Reactive ingredient
2.Magnesium oxide (MgO) 10%Reduces calcination temperature
3.Alumina (Al
2O
3)
Silicon dioxide (SiO
2) 4%
Bismuth dioxide (BiO
2)
Reinforcing fillers
4.Stannous Fluoride 6%Modifies the setting time, enhance
manipulating properties, impart anti-
cariogenic property

69. COMPOSITION
Liquid:
Ingredient % Functions
Polyacrylic acid
•Aqueous solution of acrylic
acid co-polymer with other
unsaturated carboxylic acid,
such as: itaconic acid, maleic
acid, tartaric acid etc.
•Molecular weight (25000-
50000)
•The acid concentration varies
from 32% -42% by weight
30-50%Reactive ingredient

70. SETTING REACTION
ZnO+PAA (polyacrylic acid) Zinc polycarboxylate

71. SETTING REACTION
•Settingbeginsbydissolutionofthepowderparticlesbytheacid,which
releaseszinc,magnesium,andtinions
•Thesebindandcross-linkthecarboxylgroups.
•Theresultisacross-linkedpolycarboxylatematrixphaseencapsulating
theunreactedportionoftheparticles
•The hardened zinc polycarboxylate cement is an amorphous gel matrix
in which unreactedpowder particlesaredispersed.

72. PROPERTIES
•Compressive strength = 55MPa
•Tensile strength = 6.2 MPa, lessbrittle
•pH: rapidly rises from 3 to6
•Pulpal response :mild
•Pulp protection : less irritation as the particle size and molecular weight is
higher and the acidic content is neutralizedrapidly.
•Thermal insulator -good

73. PROPERTIES
•Solubility= 0.6 % -more soluble than zinc phosphate
–Marginal dissolution is more which increases in acids like lacticacid.
–Low P/L ratio increases thesolubility
•Adhesion properties –micromechanical & chemical (carboxyl
group of toothstructure)
•Opaque
•Anticariogenic properties –less as compared to GIC.

74. MANIPULATION
CONDITIONING:
Tooth is cleaned for proper bonding
10% polyacrylic acid solution followed by rinsing with water or 1-3%
hydrogen peroxide may be used
Tooth is then dried and isolated
PROPORTIONING:
1.5 parts of powder to 1 part of liquid by weight

75. MANIPULATION
PROCEDURE:
•Powder and liquid are taken on a cooled glass slab
•Liquid is dispensed just prior to mixing
•Powder is incorporated into liquid in bulk (90%) with a stiff cement spatula
•Remaining powder is added to adjust consistency
Mixing time: 30-40 seconds
Setting time: 7-9 mins. (can be increased by cooling the glass slab)

76. MANIPULATION
•A proper mix of polycarboxylate cement is somewhat thicker in appearance
but has a shiny glossy appearance
•The glossy appearance indicates that polyacrylic acid is still available to
bond to the tooth structure
•The cement should be used at this stage
•Any delay causes loss of glossiness and formation of “cob-webbing” and it
should be discarded
•A proper mix forms a thin strand when lift up by the spatula

78. MANIPULATION

80. MANIPULATION
Notes:
1.Cement should be used while the surface is still glossy
Loss of luster indicates that the setting reaction has progressed to an extent that proper
wetting of the tooth surface by mix is no longer possible
2.After insertion, the excess isn’t removed immediately as it passes through
a rubbery stage, tends to get lifted from the cavity
Remove excess cement only when it hardens and breaks off.
3.The powder may be cooled, but the liquid shouldn’t be cooled since the
viscosity of liquid increases

81. ZINC POLYCARBOXYLATE CEMENT
ADVANTAGES
–Chemical bonding
–Good marginaladaptation to
tooth structure and metal alloys
–Mildlyacidic
–Excellent biocompatibility with
pulp
–Easy manipulation
DISADVANTAGES
•Lesscompressive strength
•Poor esthetic
•Solubilityis high
•Shorter mixing and working
time
•Need for clean surface to utilize
adhesion potential
•Anticariogenic properties not
good as GIC because fluoride
ion can’t leach out properly

82. NOTE ON ANHYDROUS ZINC
POLYCARBOXYLATE CEMENT
ZnPolyF cement is made available as single component system
That is single powder which is incorporated or later mixed with distilled water
In this system, the polyacrylic acid is freeze dried and powdered acid is
mixed with the traditional cement powder
The liquid for this material of water with pH of 4.2-4.5 compared to pH of
10-16 for polycarboxylic acid
When this powder is mixed with water, the PAA goes into solution and the
setting reaction proceeds as in similar manner as conventional P/L system

83. ZINC OXIDE EUGENOL CEMENT

84. CONTENTS
•Introduction
•Classification
•Setting reaction
•Manipulation
•Modifications
•Indications
•Contraindications
•Other ZnOE products
•Vanillate cement
•Syringate cement
•Special product (root canal sealer)

85. ZINC OXIDE EUGENOL CEMENT
Zinc oxide eugenol (ZOE) cement have been used extensively in dentistry
since1890s.
They are cements of low strength.
Also they are the least irritating of all dental cements and are known to have an
obtundent effect on exposeddentin.

86. CLASSIFICATION
Type I ZOE: For temporarycementation
Type II ZOE: PermanentCementation
Type III ZOE: Temporary filling and thermalbase
Type IV ZOE: CavityLiners

87. AVAILABLE AS
Powder and liquidor
Two –pastesystem

88. COMMERCIALNAMES
–Unmodified: Tempac –Type III, Cavitic –Type IV, Temp
bond –TypeI
–EBAaluminamodified:OpotowAluminaEBA–TypeII
–Polymer modified: Fynal –Type II, IRM–TypeIII

89. SETTING REACTION
•IntheFirstStepHydrolysisofZincOxidetoits hydroxide takes place.
•Water is essential for thereaction, dehydratedzincoxide will not react with dehydrated
eugenol
ZnO + H
2O→Zn (OH)
2
The reaction proceeds as a typical acid –base reaction unmodified
Zn (OH)
2+2HE→ ZnE
2+2H
2O resin bonded ZnOE cement
(Zinc hydroxide) ( Eugenol)-(Zinc eugenolate)
The chelate formed is an amorphous gel that tendsto:
•Crystallize imparting strength to the setmass.
•Structure of set cement: Itconsistsof particles of zinc oxide embedded in a matrix of zinc eugenolate.
•Setting time : 4-10 mins.

90. SETTING REACTION
a)It involves chelation of 2 eugenol molecules with one zinc ion to form zinc
eugenolate
b)The set mass contains residual ZnO particles bonded by a matrix of zinc
eugenolate or some free or unreacted eugenol
c)Small amount of water is necessary to initiate the reaction between
eugenol and ZnO particles.
Water hydrates ZnO to form Zn(OH)
2 which then serves as a source of zinc ions
d)Reaction is reversible because of zinc eugenolate is easily hydrolyzed by
moisture to eugenol and hydroxide
Then the cement disintegrated rapidly and exposed to oral conditions

91. MANIPULATION
Power –Liquid System
Powder / liquid ratio:4:1-6:1wt.%
After shaking the bottles gently, measured quantity of powder and liquid are dispensed onto a
cool glass slab.
The bulk of the powder is incorporated into the liquid and saturated thoroughly ina circular
motion with a stiff bladed stainless steel spatula.
Smaller increments are then added until the mix iscomplete.

92. MANIPULATION
1.Proportioning: the powder bottle should be shaken well before
dispensing to get uniform composition. The powder is dispensed at 1 end
of the mixing slab/pad. There’s no need of incorporation of the powder
to small increments in the beginning since the reaction isn’t exothermic
and the pH is around 7.
Mixing: initiated by the addition of bulk increments. The mix is thoroughly spatulated and
then a series of smaller increments is added until a required consistency is achieved.
The correct mix can be rolled on a glass slab for restorative consistency.
2.Proportioning and mixing: more powder is required for cementing, i.e.
propagation. The powder is mixed with liquid in small portions with
vigorous spatulation until correct amount has been incorporated.

93. MANIPULATION
In order to obtain optimum properties, it is important to use as high powder
liquid ratio as possible, i.e. 3.59 gm/ml for cementation and 5-6 gm/ml for
liners and bases
The cement mixes readily to a very fluid consistency even at a higher P/L
ratio. Reverse spatulation is required for about 2 mins to incorporate all the
powder.
Because of the long working time, adequate setting time in the mouth
should be allowed.

94. MANIPULATION

95. MANIPULATION
2 paste system:
Equal lengths of each paste are dispersed and mixed until a uniform color is
observed.

96. FACTORS AFFECTING SETTING TIME
FACTORS To decrease setting time To increase setting time
1.P/L ratio High Low
2.Temp. of spatula
and mixing slab
Warm glass slab and spatula Cool spatula and glass slab
(provided the temp. not lower
than dew point)
3.Spatulation timeShorter Longer
4.Amount of water
(humidity)
High Low
5.Rate of powder
incorporation
Introduction of bulk quantity of
powder into liquid
Introduction of small quantity of
powder into liquid

97. COMPOSITION-UNMODIFIED ZnOE
POWDER Ingredients % Functions
1. ZnO (USP or arsenic free)69% Reactive ingredient
2. White rosin or hydrogenated
resin
29.3%Reduces the brittleness of the set
cement
3. Zinc acetate 0.7% Serves as an accelerator by providing
zinc ions
4. Zinc stearate 1% Plasticizer
LIQUIDIngredients % Functions
1. Eugenol/oil of
cloves
85%For the reaction with zinc or reactive
ingredient
2. Olive oil/cotton
seed oil
15%Plasticizer and to control the viscosity

98. UNMODIFIED ZnOE
ADVANTAGES
Obtundent effects on the pulpal tissues
Good sealing ability
Resistance to marginal penetration
DISADVANTAGES
Solubility and disintegration in oral
fluids
No anti-cariogenic property
Lack of adhesion to the tooth structure
Low strength and abrasion resistance

99. USES
For temporary restoration (it has got good obtundent properties)
Temporary cementation of restoration
Cavity liners in deep cavity preparations
Pulp cappingagent
For temporary and permanentcementation
As a base
Secondary use –root canalrestorations.

100. MODIFIED ZINC OXIDE EUGENOL
CEMENTS
1.EBA (ethoxy benzoic acid)-alumina modifiedcements
2.Polymer reinforced ZOEcement
These were introduced to improve the mechanical properties of zinc oxide
eugenolcement

101. COMPOSITION –EBA ALUMINA ZnOE
POWDER % FUNCTIONS
ZnO 64% Reactive ingredient
Hydrogenated rosin 6% To reduce the brittleness and film thickness and to
improve mixing qualities
Alumina / fused quartz 30% For strength or reinforcing filler to increase compressive
and shear strength
LIQUID % FUNCTIONS
Eugenol 37.5%•Reactive ingredient
O-EBA 62.5%•To improve the strength of the cement
•To promote the formation of a stronger
crystalline matrix

102. SETTING REACTION
For EBA alumina:
ZnO+ eugenol / EBA Eugenolate-2-ethoxy benzoate
(matrix)
Reaction appears to involve chelate salt formation between EBA, eugenol
and zinc oxide

103. PROPERTIES
Thermal properties –their thermal insulating properties are excellent
Solubility and disintegration –The solubility of the set cement is highest among
the cements (0.4% -wt.) they disintegratein oralfluids
Adhesion –they do not adhere well to the enamel and dentin. This is one reason
why they are not often used for final cementation of crowns andbridges.
Biologicalproperties.
pH and effect on pulp (pH is 6.6 to 8) they are the least irritating of allcements. Pulpal
responses aremild.
They have soothing effect on thepulp.

104. USES
Permanent cementation of restoration
Temporary restorations
Base / liner under restorative material (Eg.: amalgam, silicate,
silicophosphate, GIC)
For sealing coronal portion of tooth undergoing endodontic treatment

105. EBA ALUMINA ZnOE
ADVANTAGES
•Long working time
•Easy manipulation
•Good flow and strength
characteristics
•Low irritation to the pulp
DISADVANTAGES
•Critical proportioning i.e. higher
powder-liquid ratio for optimum
properties
•Hydrolytic breakdown in oral fluids
•Liability to plastic deformation (poor
retention) than ZnPO
4cement

106. RESIN REINFORCED ZINC OXIDE
EUGENOL CEMENT
Reinforcing polymer incorporated into the powder
It gives the cement strength to resist condensation forces and to ensure
adequate life when used as a temporary restorative material
Reinforcing material is incorporated in the powder instead of liquid, so the
mixing properties are excellent
Though it is reinforced, can be removed easily when used as temporary
material

107. COMPOSITION –RESIN BONDED ZnOE
POWDER % FUNCTIONS
ZnO 90%Main reactive ingredient
Finely divided natural or
synthetic resins such as
polystyrene or PMMA
Some acidic resins such as
colophony etc.
10%To improve the strength of the set cement
LIQUID % FUNCTIONS
Eugenol 85% Main reactive ingredient
Olive oil 14% Plasticizer and controls the viscosity as well
Acetic acid Traces As an accelerator
Thymol or 8-hydroxy
quinolone
Traces Antimicrobial agent

108. SETTING REACTION
Similar to that of ZnOE cements
Acidic resins if present, might react with ZnO
Strengthens the matrix

109. MANIPULATION
•Powder and liquid dispensed on a dry glass slab
•50% of powder is mixed into liquid and remaining in small parts with
vigorous spatulation
•Mix appears stiff, which improves the plasticity after additional 5-10 seconds
mixing
•Working time: long
•Setting time: 6-10 mins (sets faster in mouth due to heat and moisture)

110. PROPERTIES
Compressive strength 48 MPa (7000 psi)
Tensile strength 4.1 MPa (600 psi)
Modulus of elasticity 2.5 GPa
Film thickness 32 μm
Solubility and disintegration 0.03% wt.
Pulp response Moderate: similar to unmodified ZOE
Abrasion resistance and toughness Improved

111. USES
Permanent cementation
Luting agent for restoration
As cavity liners
As intermediate or temporary restorations

112. CONTRAINDICATIONS
As with other Eugenol containing materials, the polymerization of acrylic
direct filling materials (acrylic resins and composite resins) and temporary
crown and bridge materials is inhibited and use with these materials must be
avoided

113. RESIN BONDED ZnOE
ADVANTAGES
Adequate strength for final
cementation of restoration
Good obtundent effect or minimal
reaction to pulp
Good initial sealing properties
Easy manipulation
DISADVANTAGES
Minimal mechanical properties for
luting i.e. lower strength, higher
solubility and disintegration than
ZnPO
4cement
Hydrolytic breakdown when
exposed to oral conditions
Softening and discoloration of some
resin restorative materials

114. PROPERTIES
P/L Mixing
time
(min.)
Setting
time
(min.)
Film
thickness
(microns)
Compressive
strength
(MPa)
Tensile
strength
(MPa)
Modulus
of
elasticity
(GPa)
Solubility
(%)
A.5:1 by
mass
1 min4-10
mins
25 μ 13-38 1.2-2.80.22 0.04%
B.6:1 1 min6-10
mins
32 μ 35-55 5-8 2-3 0.08% by
weight
C.3.5 gm/ml2 mins7-13
mins
40-70 μ 35-70 3-6 5 0.05%
A: Unmodified ZnOE
B: Resin bonded
C: EBA-Alumina

115. OTHER ZnOE PRODUCTS
Non-eugenol Zinc oxide:
Vanillate and syringate cements
Special ZnOE product (Root canal pastes)

116. VANILLATE AND SYRINGATE CEMENTS
Recently cements have been developed containing hexyl vanillate and ortho ethoxy
benzoic acid (O-EBA)
HV-OEBA as a substitute for eugenol
This liquid is mixed with zinc oxide (ZnO) powder
Dispensing: powder-liquid system
Components:
Powder: ZnO (64%), Al
2O
3(30%), Hydrogenated rosin (6%)
Liquid: EBA (87.5%), n-hexyl vanillate (2.5%)
These cements have high strength and low solubility, and are suitable for patients
sensitive to eugenol

117. SPECIAL ZnOE PRODUCT (ROOT CANAL
SEALERS)
Modification of ZnOE cavity lining materials
These pastes can be used alone or in combination with gutta percha or
silver points
This material contains :
•Antibiotics eg.: Tetracylines, Steroids, Disinfectants (para-formaldehyde),
radio-opacifiers (BaSO
4,BiO
2)

119. SILICATE CEMENTS

120. CONTENTS
•Introduction
•Composition
•Setting reaction
•Properties
•Merits
•Demerits
•Indications
•Contraindications

121. SILICATE CEMENTS
A.D.A. No: 9
Dispensing: supplied as powder liquid

122. COMPOSITION
POWDER Ingredients %
1. SiO
2 (silicon dioxide) 38%
2. Al
2O
3 (aluminium oxide) 30%
3. Na
3PO
4/ Ca
3(PO
4)
3
CaO (trisodium phosphate / calcium phosphate /
calcium oxide
8%
4. Calcium fluoride (CaF
2)
Na
3AlF
6 (sodium hexa-fluoride-aluminate)
4%
LIQUID Ingredients %
1. H
3PO
4 (phosphoric acid) 42%
2. AlPO
4(aluminium phosphate) 10%
3. Zn
3(PO
4)
2 (zinc phosphate) 8%
4. H
2O 40%

123. SETTING REACTION
Silicate powder + H
3PO
4 reaction matrix
(base) (acid)
H
+
H
2PO
4-(dihydrogen phosphate)
(cement powder)

124. PROPERTIES
Pulpal response:positive control severe irritant
Setting time: 3 mins-9 mins
Compressive strength: 167 Mpa
Tensile strength: 15 MPa
Solubility: ADA: <1% and commercial product: 0.7%
Surface hardness: 70 KHN (knoophardness number)
Acidity (pH at 2 mins): 2.8

125. SILICATE CEMENTS
MERITS
•Anticariogenic property or ability to
prevent marginal caries
•Good initial aesthetics
•Good compressive strength
DEMERITS
•Severe irritant to pulp
•Readily soluble in oral fluids
•Brittleness
•Low resistance to impact, stress and abrasion
•Moisture sensitivity
•Lack of color stability
•Lack of adhesive bonding to the tooth structure

126. SILICATE CEMENTS
INDICATIONS
•Class III anterior restoration
•For patient having high caries
index; i.e. rampant caries
•As an intermediate restorations
CONTAINDICATIONS
•Class II cavities in posterior teeth
•Biting edges of anterior teeth
•For mouth breathers

128. SILICOPHOSPHATE CEMENT

129. CONTENTS
•Introduction
•Composition
•Setting reaction
•Properties
•Merits
•Demerits
•Indications
•Contraindications

130. SILICOPHOSPHATE CEMENT
A.D.A. No: 21
Types:
Type I: cementing medium
Type II: temporary posterior filling material / intermediate restoration
Type III: dual purpose cement
Dispensing: supplied as powder-liquid

131. COMPOSITION
POWDER INGREDIENTS %
1. Silica 35%
2. Alumina (Al
2O
3) 25%
3. ZnO (zinc oxide) 15%
4. MgO (magnesium oxide) 5%
5. CaO (calcium oxide) 5%
6. CaF
2/ NaF/ Na
5AlF
6
(calcium fluoride / sodium
fluoride / sodium aluminium
fluoride)
15%
LIQUID INGREDIENTS %
1. H
3PO
4 (phosphoric acid)50%
2. AlPO
4 (aluminium
phosphate)
2%
3. Zn
3(PO
4)
2 (zinc
phosphate)
3%
4. H
2O 45%

132. SETTING REACTION
Zinc alumino silicate + H
3PO
4 Zinc alumino phosphate silicate
(phosphoric acid) gel (reaction matrix)

133. PROPERTIES
Pulpal response:greater potential
for pulpal irritation
Compressive strength:
Type I: 140 MPa
Type II: 170 MPa
Tensile strength: 71 MPa
Solubility:
Type I: 1.5%
Type II: 1.0%
Surface hardness:70 KHN

134. SILICOPHOSPHATE CEMENT
MERITS
•Higher strength
•High abrasion resistance
•Higher toughness than Zn
3(PO
4)
2
•Lower solubility
•Degree of translucency
DEMERITS
•Greater potential for pulpal irritation
•Less satisfactory mixing and
rheological property
•Higher film thickness

135. SILICOPHOSPHATE CEMENT
INDICATIONS
•Cementation of fixed restorations esp. porcelain due
to their translucency
•Cementation of orthodontic bands because of less
decalcification in adjacent tooth enamel
•Temporary posterior restoration, intermediate and
deciduous restoration
•As die materials (positive reproduction of prepared
tooth)
CONTRAINDICATIONS
•Permanent restoration

136. NOTE ON ANTI-CARIOGENIC PROPERTY
It is due to the release of fluoride from restoration
These ions are responsible for decreasing the chance of decay of adjacent
tooth
Fluoride ion will be released throughout the life of the restoration
Fluoride leaching from the cement acts as an anticariogenic agent.

137. PHYSIOCHEMICAL MECHANISM OF CARIES
Fluoride ion released during the setting and subsequent dissolution of
silicate cement reacts with the adjacent tooth to form a structure that is more
resistant to acid decalcification and reduces enamel solubility
The surface energy of fluorapatite is lower than hydroxyapatite making the
adhesion of unwanted cariogenic substance such as dental plaque more
difficult
Release of fluoride ion in low concentration contributes to the formation of
acid resistant crystal.

138. RESIN CEMENTS

139. CONTENTS
•Introduction
•Applications
•Classification
•Composition
•Properties
•Manipulation

140. RESIN CEMENTS
•Based on methyl methacrylate, have been used since 1952 for cementation
of inlays, crowns etc.
•Developed with the development of composite resins
•They are low viscosity flowable composites

141. APPLICATIONS
To bond orthodontic brackets to acid-etched enamel
Cementation of porcelain veneers and inlays
Cementation of all-porcelain crowns and FPDs
Cementation of etched cast restorations

142. CLASSIFICATION
Based on curing system:
Chemical cure
Light cure
Dual cure

143. RESIN CEMENTS
Chemically activated resins: used for all types of restoration
Light activated resins: can’t be used in all situations because of problems in
light penetration
Dual cure resins: used when the material being bonded allows some
degree of light penetration
The areas where light cannot penetrate cure subsequently by chemical reaction

145. SUPPLIED AS
Chemical cured:
2 paste system containing base and accelerator
Single paste system with activator in the bonding liquid
Light cured: single paste system
Most systems include a bonding agent and etchant
Commercial names: Panavia F, Infinity, Resilute (Pulpdent), Transbond
XT(3M), Maxcem Elite (Kerr), Variolink Esthetic (Ivoclar)

146. COMPOSITION
Similar to that of composite resin

147. PROPERTIES
Compressive strength 180 MPa (26000 Psi)
Tensile strength 30 MPa (4000 Psi)
Film thickness 10-25 μm
Biological properties Pulp irritant. Pulp protection with Ca(OH)
2or
GIC liner in the areas near to pulp
Solubility Insoluble in oral fluids
Polymerization shrinkage High
Adhesion properties Do not adhere to tooth structure, may lead to
microleakage if used without etching and
bonding
Bond strength to enamel 7.4 MPa (1070 Psi). Usually stronger with
enamel.

148. POLYMERIZATION
I.Chemically by peroxide-amine system
II.By light activation
III.By both chemical and light activation (dual cure)

149. MANIPULATION AND TECHNICAL
CONSIDERATIONS
1)Etching the restoration
2)Etching the tooth surface
3)Bonding and curing
4)Removal of excess cement

150. ETCHING THE RESTORATION
Etching metal:
•Metal surface can be etched or roughened by blasting 30-50 μm alumina to
improve retention
•Etching is more effective
•Process is carried out in a electrolyte bath containing an acid like sulfuric
acid-also known as electrochemical etching
•Silica coating can be used to improve bonding

151. RESIN CEMENTS
Etching porcelain:
•Ceramic is highly inert material and is immune to attack by most acids
•Can be etched by using hydrofluoric acid
•Esthetic surfaces are protected with coating of wax.

152. RESIN CEMENTS
Orthodontic brackets:
A fine mesh on the bonding side of bracket helps to improve its retention
Cement flows into the mesh and locks to provide good mechanical retention
Coating with organosilane improves bond strength.

153. BONDING AND CURING
Chemically activated systems:
2 paste systems: 2 components are combined by mixing on a paper pad
for 20-30 seconds
Single paste system with activator in bonding agent: the activator is
present in bonding agent
Bonding agent is painted on the etched surface and restoration
Setting occurs when the cement on the restoration contacts bonding agent on tooth

154. DUAL CURE SYSTEM
2 components are mixed and light cured
Exposure time should never be <40 seconds
Light curing gives high initial strength
Light curing polymerizes the exposed cement at the margins of the
restoration which is affected by air inhibition

155. REMOVAL OF EXCESS CEMENT
•Excess cement removal is critical
•Removal can be very difficult due to strength of the material
•Should be attempted soon after seating before the material has hardened
•Some manufacturers recommend a partial light cure to facilitate removal
followed by completion of curing

156. COMPOMERS

157. CONTENTS
•Introduction
•Composition
•Setting reaction
•Properties
•Manipulation

158. COMPOMERS
Compomers / poly acid modified composites are used for restorations in low
stress bearing areas
Recent product is recommended by manufacturer for class I and class II
restorations in adults
Recommended for patients at medium risk of developing caries

159. COMPOSITION AND SETTING REACTION
Contain poly acid-modified monomers with fluoride-releasing silicate glasses
Formulated without water
Some compomers have modified monomers that provide additional fluoride release
Volume % filler ranges from 42%-67%
Average filler particle size: 0.8 to 50 μm
Available as: single paste packaged in compules and syringes

160. COMPOSITION AND SETTING REACTION
•Setting occurs by light-cured polymerization
•But an acid-base reaction also occurs as the compomer absorbs water after
placement and upon contact with saliva
•Water uptake is also important for fluoride transfer

161. PROPERTIES
Release fluoride by mechanism similar to that of glass and hybrid ionomers
Because of lower amount of glass present in compomer, the amount of
fluoride release and its duration are lower than those of glass and hybrid
ionomers
They do not recharge from fluoride treatment or brushing with fluoride
dentifrices / toothpastes as much as glass and hybrid ionomers

162. PROPERTIES
Properties
Flexural strength (MPa) 65-125
Flexural modulus (GPa) 4.5-14
Flexural fatigue limit (MPa) 70
Compressive strength (MPa) 180-250
Compressive modulus (MPa) 6-7
Diametral tensile strength (MPa)25-40
Linear polymerization shrinkage (%)-------
Color stability, accelerated aging2.1
Color stability, stained by juice/tea5.7

163. MANIPULATION
•Packaged in unit-dose compules
•They require a bonding agent to bond to tooth structure

164. REFERENCES
1.Philips’ science of dental materials (1
st
South Asia Edition)
2.Craig’s restorative dental materials (12
th
edition)

165. QUESTIONS
LONG QUESTIONS:
1.Classify dental cements. Write the composition, uses and properties of
Zinc Phosphate Cement (15 marks)
2.Classify dental cements. Write in detail about Zinc oxide eugenol cement.
3.List the luting cements. Write in detail about polycarboxylate cement.

166. QUESTIONS
WRITE SHORT NOTES ON: (5 marks each)
1.Anticariogenic properties of a restorative material
2.Properties of Zinc Phosphate Cement
3.Write in brief the properties, advantages and disadvantages of Zinc Phosphate
Cement / ZnOE
4.Low strength bases
5.Calcium hydroxide
6.Zinc Oxide Eugenol paste
7.Anticariogenic property of silicate cement
8.Properties of ZnPO
4cement / ZnOE

167. QUESTIONS
WRITE SHORT NOTES ON: (5 marks each)
1.Composition and setting reaction of ZnOE paste
2.Uses of varnish
3.Zinc Phosphate Cement
4.Dental varnish
5.Dual cure and tri-cure system