3. INTRODUCTION
Cement is defined as a substance that hardens to act as a base,
liner, filling material, or adhesive to bind devices and prostheses
to tooth structure or to each other.
- Phillips’ science of dental materials 11th edition
Dental cements are generally inorganic, nonmetallic substances
that harden to act as a base, liner, or restoration or as an
adhesive to bind devices or prosthesis to tooth structure.
Dental cements are commonly powder-liquid systems that set via
acid-base reaction or chelation. They are used for restorative,
endodontic, orthodontic, periodontic as well as surgical
procedures.
Last 2 decades have seen a variety of changes in the dental
cement composition and also introduction of newer advanced
biocompatible materials.
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8. BASED ON TYPE
TYPE I : LUTING AGENT includes Temporary cements
- Powder-Liquid --- hardens
- Paste-Paste --- remains soft
TYPE II : LUTING AGENT for permanent restoration
TYPE III : TEMPORARY LINER OR BASE APPLICATION
TYPE IV : PERMANENT LINER OR BASE APPLICATION
9. IDEAL REQUIREMENTS
Non-toxic, Non-irritant to pulp and tissues
Insoluble
Adhesion to enamel and dentin
Bacteriostatic
Obtundant effect on pulp
Thermal, chemical and electrical insulation
Optical properties
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10. ZINC PHOSPHATE CEMENT
Introduced by Dr. Otto Hoffman during the
1800s
One of the oldest cement
Acts as the gold standard by which newer
materials are compared.
APPLICATION
Luting of restorations
Luting of orthodontic bands
High strength bases
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12. TYPES
Type I –
Fine Grained : (Film Thickness less than 25µm)
Luting permanent metallic restorations
Cementation of orthodontic bands
Type II –
Medium Grained : (Film Thickness of 40µm)
High strength thermal insulating base
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13. SETTING REACTION
Phosphoric acid attacks the surface of the particles
Releases zinc ions into the liquid
Aluminium forms complexes with phosphoric acid, reacts with zinc
forming zinc aluminophosphate gel.
Exothermic reaction.
The final set cement is a cored structure consisting primarily of
unreacted zinc oxide particles embedded in a cohesive amorphous
matrix of zinc aluminophosphate
3ZnO+2H3PO4 +H2O Zn3(PO4)2.4H20
(zinc phosphate)
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14. Frozen Glass slab Technique:
To prolong working time and shorten setting time.
Glass slab cooled at 6°C or – 10°C.
50 – 75% more powder incorporation.
Working time is increased by 4 – 11 mins
Setting time shortened by 20 – 40%
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15. FACTORS AFFECTING SETTING
TIME
Reducing the P:L ratio increases the working time and setting
time
Low initial pH which will impair the mechanical properties
Smaller increments mixed for first few increments
Prolonging the spatulation time
Temperature of the mixing slab
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16. BIOLOGIC PROPERTIES
Freshly mixed ZnPO4 - highly acidic pH - pulpal irritation
Very thin mixes must be avoided as it can be highly acidic.
Pulp protection -
High P:L ration must be used, Calcium hydroxide or cavity
varnish
ADHESION :
By mechanical interlocking of the set cement with cavity
surface roughness
Acts as a good thermal insulator.
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17. MODIFIED ZINC PHOSPHATE
CEMENT
COPPER & SILVER CEMENTS
Black copper cements : Cupric oxide
Red copper cements : Cuprous oxide
Depending on the type of copper cement, concentration of
the copper varies between 2% and 97%.
Lower P:L ratio – for satisfactory manipulation
characteristics
Highly acidic
Higher solubility
Lower strength than ZnPO4
Less anticariogenic property
Silver cements : contain small percentage of salts of silver
phosphate
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18. FLUORIDE CEMENTS
• Stannous fluoride (1-3%)
• Higher solubility and lower strength – due to
dissolution of Fluoride
• Fluoride uptake by enamel : Reduced enamel
solubility and Anticariogenic
MODIFIED ZINC PHOSPHATE
CEMENT
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19. SILICATE CEMENT
Fletcher in 1871
Oldest direct tooth colored materials
Steenbock later introduced an improved version
of the cement
The use of dental cement as a restorative
material began with silicate cement.
Silicates are rarely used nowadays. This is due
to development of better materials like composite
resin and glass ionomer cement
Commercial Names-
Biotrey
Silicap
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21. Properties
Compressive stength -180MPa
Tensile strength – 3.5 Mpa
Silicates are translucent and resemble porcelain in
appearance
Severe irritant to pulp
dissolve and disintegrate in oral fluids
Anticariogenic properties- contain fluoride up to 15%
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22. Clinical Significance
The incidence of secondary caries is markedly less around
the silicate cement restoration.
fluoride provides a source of fluoride uptake to the adjoining
tooth structure during insertion and hardening of the cement.
This results in a substantial reduction in enamel acid
solubility much as in a topical application of fluoride solution
It exhibit good esthetic qualities for a short time after
insertion.
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23. Disadvantages
Severe pulp irritation due to low Ph (5 -3.2)
It lacks stability in oral fluids , disintigration
loss of esthetic qualities due to discoloration
Shrinkage on setting
Rubber dam is essential for successful silicate restoration.
Are not being used recently
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24. SILICOPHOSPHATE CEMENTS (ADA
Sp. No.96)
Presence of silicate glass: translucency, improved strength,
fluoride release.
APPLICATIONS
Type I : Cementation of fixed restorations
Type II : Provisional restorative material
Type III : Dual purpose material
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28. ZINC POLYCARBOXYLATE
CEMENT
• Dennis Smith : 1968
• First cement system with adhesive bond to
tooth structure
• Also known as polyacrylate cement
APPLICATION
• Luting alloy restorations
• Thermal insulating bases
• Cementing orthodontic bands
• Cementing SS crown in pediatric
dentistry
Commercial names-
• Poly F (Dentsply)
• Durelon
• Carboco (voco)
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30. Methods to Increase the working
time
Cooling glass slab :
Thickening of the liquid
Powder refrigerated before mixing
Reaction occurs on cool surface, cool temperature retards the
reaction without thickening of the liquid.
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31. SETTING REACTION
particle surface dissolution by the acid
release of zinc, Mg and Sn ions
Ions bind to the polymer chain via the carboxyl groups.
These ions react with carboxyl of adjacent polyacid chains
cross linked salt is formed as the cement sets.
The hardened cement consists of an amorphous gel matrix
in which unreacted particles are disposed
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32. PROPERTIES
• Solubility in water is low
• In organic acid with pH < 4.5 : increased solubility
• Reduced P:L ratio : increases solubility in oral cavity
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33. BIOLOGIC EFFECTS-
Good biocompatibility
Low intrinsic toxicity
Rapid rise in pH towards neutrality
Fluoride release
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34. ZINC OXIDE EUGENOL (ADA SP.
NO. 30)
• Introduced by Chrisholm in 1873
• Commonly used for luting and intermediate
restorations
• Obtundant property on exposed dentin
APPLICATION
• Longterm and short-term luting agents
• Temporary and intermediate restorations
• Root canal sealers
• Surgical packs
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35. TYPES (ADA Specification No. 30)
Type I : Temporary restorations
Type II : Permanent cementation of restorations
Type III : Temporary restoration, thermal insulating bases
Type IV : Cavity Liner
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37. SETTING REACTION
Hydrolysis of the ZnO
ZnO + H2O Zn(OH)2
Zn(OH)2 + 2HE ZnE2 + 2H20
Zinc hydroxide reacts with acid eugenol forming zinc eugenolate which
crystalizes and strengthens the cement
Set cement also contains free zinc oxide embedded in a matrix of zinc
eugenolate
Reaction is reversible, zinc eugenolate can easily be hydrolysed by
moisture in the oral cavity to eugenol and zinc hydroxide
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42. SETTING REACTION
Similar to ZnO eugenol
Acidic resin such as colophony may react with zinc oxide,
strengthening the matrix
MANIPULATION
(Method similar to ZnO eugenol)
More powder is required for cementing mix
Proper P:L ratio must be followed for adequate strength
properties
Mixing pad/slab should be completely dry
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43. PROPERTIES
Solubility is lower than ZnO eugenol cement due to the presence of resin
BIOLOGIC EFFECTS
• Inflammatory reaction in the connective tissue is present
• Softening and discoloration of the resin material
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45. EBA MODIFIED ZINC OXIDE
EUGENOL CEMENT
APPLICATION
Cementation of inlays, crowns, FPD’s and for provisional restoration
Base / lining material
COMPOSITION
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46. SETTING REACTION
Not fully known
Appears to form chelate salt between EBA, eugenol and zinc oxide.
MANIPULATION
Similar to ZnO eugenol
Cement mixes readily to very fluid consistency even at a high P:L
ratio
For optimal properties : use high P:L ratio as possible
3.5 g/ml : cementation
5 – 6 g/ml : liners and bases
Vigorous spatulation is required for about 2 mins to incorporate all of
the powder
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48. NONEUGENOL CEMENTS
EBA- ethoxy benzoic acid
Advantages over ZOE:
No irritation to soft tissue
Compatible with acrylic resin materials
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49. ADVANTAGES
Easy manipulation
Long working time
Good flow characteristics
Good strength characteristics
Minimal irritation to the pulp
Best suited to cutting 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
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50. GLASS IONOMER CEMENT
Synonyms
Poly (alkenoate) cement
GIC (glass ionomer cement)
ASPA (alumino silicate polyacrylic acid)
Manmade dentin
These cements have the combined properties of silicate cements and
polycarboxylate cements.
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51. CLASSIFICATION
Type I - Luting
Type II - Restoration
Type III - Liner and bases
Type IV - Pit & Fissure sealants
Type V - Orthodontic cement
Type VI - Core build up
Type VII - high fluoride releasing
Type VIII - ART
Type IX - geriatric and pediatric uses
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53. LIQUID
Polyacrylic acid – 40-50%
Tartaric acid – improves the handling characteristics
increases working time
In most current cements -Acid is in the form of a copolymer
with-
• Itaconic acid
• Malic acid
• Tricarboxylic acid
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54. CHEMISTRY OF SETTING
powder and liquid are mixed to form a paste,
the acid etches the surface of the glass particles and calcium, aluminum,
sodium, and fluoride ions are leached into the aqueous medium.
The polyacrylic acid chains are cross-linked by the calcium ions that are
replaced by aluminium ions within the next 24 hours.
Sodium and fluorine ions do not participate in cross- linking of the
cement.
Some of sodium ions may replace the hydrogen ions of carboxylic group,
whereas the remaining ions are dispersed uniformly within the set
cement along with fluorine ions.
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55. MODIFICATIONS
Metal reinforced glass Ionomer cement
Glass ionomer cements can be reinforced by physically
incorporating silver alloy powder (spherical amalgam alloy)
with glass powder (type II glass ionomer cement), usually
referred as SILVER ALLOY ADMIX / MIRACLE MIX.
It can be also reinforced by fusing glass powder to silver
particles through sintering, which is referred as CERMET.
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56. RESIN MODIFIED GLASS IONOMER
CEMENT
(HYBRID IONOMER or Dual-Cured GIC)
COMPOSITION
POWDER
Contains radio opaque, ion-leachable fluoroaluminatesilicate glass
particles and micro encapsulated catalyst system and initiators for light
curing and chemical curing
LIQUID
Contain water and polyacrylic acid
Polyacrylic acid modified with methacrylate and hydroxyethyl
methacrylate (HEMA) monomers
Methacrylate and hydroxyethyl methacrylate (HEMA) are responsible
for polymerization
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57. SETTING REACTION
The initial setting reaction :
polymerization of methacrylate group
The slow acid-base reaction will ultimately be responsible for
the unique maturing process and the final strength.
The overall water content is less for this type of material to
accommodate the polymerizable ingredients
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58. PROPERTIES
The fluoride release is at the same level as conventional
glass ionomr cement.
Tensile strengths are higher than conventional glass ionomr
cement.
Increase in tensile strength is mainly attributable to their
Lower elastic modulus
The greater amount of plastic deformation that can be
sustained before fracture occurs.
The mechanism for bonding to tooth structure is the same as
that for conventional glass ionomr cement
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59. Less ionic activity is expected because of the reduction in
carboxylic acid in the liquid of resin-modified glass ionomers.
Bond strength to tooth structure can be higher than that of
conventional glass ionomer cements.
Exhibit a higher bond strength to resin based composites.
Lower water and carboxylic acid content also reduce the
ability of the cement to wet the tooth substrates which can
greatly increase microleakage compared with conventional
glass ionomer cements.
The biocompatibility of hybrid glass ionomers is comparable
to that of conventional glass ionomer cements.
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60. INDICATIONS
Liners
Fissure sealants
Bases
Permanent cementation of crowns and bridges to tooth structure
Core build ups
Cementation of posts
Bonding of orthodontic appliances
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61. Restoration of class I, III or V .
Repair materials for damaged amalgam cores or cusps.
Retrograde root filling material.
Most products are not recommended for cementations of all
ceramic inlays, onlays / crowns because of their water
sorption, which leads to expansion, which can cause
cracking of the ceramic restoration.
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62. RESIN CEMENTS
COMPOSITION AND CHEMISTRY
The basic COMPOSITION of most modern resin cements is
similar to that of composite resin filling materials, but generally
have lower concentrations of filler particles.
The filled resin cements consist of a resin matrix with inorganic
fillers that are bonded to the matrix via coating with organo
silane coupling agent.
The resin matrices generally are diacrylate monomers diluted
with low- viscosity dimethacrylate monomers.
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63. Some of them incorporate the bonding mechanism utilized by
dentin bonding agents in the form of organophosphates,
HEMA (hydroxymethyl methacrylate) and the 4 META (4
methacrylate trimellitic anhydride) system.
Bonding of the cement to enamel can be attained by the
acid- etch technique.
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64. PROPERTIES
Setting time – 2-4 minute
Film thickness - < 25 micro meter
Compressive strength- 70-172 MPa
Solubility & disintegration in water – 0.00-0.01% weight
Pulp response – Moderate
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65. CHEMISTRY OF REACTION
Polymerization is achieved by the conventional peroxide-amine
system or light activation.
A few systems utilize both mechanisms and are referred to as
“dual cure” materials.
Light cured cements are normally used for cementation of
restorations or appliances that transmit light.
Fillers –Silica or glass particles( 10-15 micro meter diameter)
-Colloidal silica
The filler levels vary from about 30% up to around 80% by weight.
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66. With Respect to bonding to dentin, the adhesive cements
that incorporate the organophosphates, HEMA (hydroxiethyle
methacrylate) or 4 META (4 methacrylethyle trimellitic
anhydride) adhesion systems generally develop reasonably
good bond strengths to dentin.
Some of the other commercial resin cements furnish a bond
agent as a separate component of the cement system.
It should be emphasized that bonding may be more critical
for resin cements than for some other types of cement
because they possess no anticariogenicity.
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67. BIOLOGICAL PROPERTIES
Resin cements just like the composite restorative resins are
irritating to the pulp.
Thus pulp protection via a calcium hydroxide base is
important when one is cementing an indirect restoration in a
cavity that involves dentin.
If the bonding area involves only enamel, the irritating
properties of the monomers are not of consequence.
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68. LIGHT CURED CEMENTS are single component systems
just as are the light-cured filling resins.
They are widely used for cementation of porcelain and
castable glass restorations and for direct bonding of ceramic
orthodontic brackets.
The time of exposure to the light that is needed for
polymerization of the resin cement depends upon the light
transmitted through the ceramic restoration or bracket and
the layer of polymeric cement.
The time of exposure to the light should never be less than
40 seconds.
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69. The DUAL-CURE CEMENTS are two-component systems
and require mixing just as for the chemically activated
systems.
The chemical activation is very slow, which provides
extended working time until the cement is exposed to the
curing light, at which point cement solidifies rapidly.
It then continues to gain strength over an extended time
period owing to the chemically activated polymerization.
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70. APPLICATIONS
Used to attach either resin or ceramic veneers to the surface
of anterior teeth using the acid etch technique.
It is a choice in cementation of resin bonded bridges.
These are widely employed for intermediate prosthesis.
It is also involves in direct attachment of orthodontic brackets.
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71. CALCIUM HYDROXIDE
Hermann – 1920
Useful water setting cement which has osteoconductive
and osteoinductive property
As a pulp capping agent facilitates formation of reparative
dentin– alkaline pH, antibacterial and protein lyzing
property.
TYPES:
Non setting (pH : 11 – 13) – intracanal medicament
Setting (pH : 9 – 10) – cavity liner
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72. APPLICATION
Liners in deep cavity preparations
Intracanal medicaments
Direct and indirect pulp capping
Apexification procedures
COMPOSITION
2 Pastes – Base and Catalyst
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73. SETTING REACTION
Calcium hydroxide reacts with the salicylate forming a chelate,
amorphous calcium disalicylate.
Hydroxyl ions from the cement neutralize the acids produced from the
clast cells and create an optimum pH for pyrophosphatase activity
necessary for mineralization.
MANIPULATION
Equal lengths of the 2 pastes are mixed to a uniform color
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75. BIOLOGICAL EFFECTS
Strong Antibacterial Action
Ionic dissociation of calcium hydroxide into calcium ions and
hydroxyl ions. (54.11% and 45.89% respectively)
Hydroxyl ions induces chemical injury on the organic
components of thecytoplasmic membrane of the bacteria,
causing destruction of phospholipids or unsaturated fatty acids.
Dentin Bridge Formation (Pulp Capping)
Activates enzymes such as alkaline mineralization
phosphatase which is responsible for mineralisation
Free calcium hydroxide helps in menaralisation of carious
dentin
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77. CONCLUSION :
No single type of cement satisfies all of the ideal
requirements or is best suited for all indications in dentistry
Each situation must be evaluated based on the
environmental, mechanical and biological factors and finally
decide on which material to be used in each case.
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