Dental cements

dental cement

1. PRESENTED BY-DR NADEEM AASHIQ
MDS 2ND YEAR
1

2. CONTENT
INTRODUCTION
CLASSIFICATION
CHARACTERISTIC PROPERTIES OF DENTAL CEMENTS
ZINC PHOSPHATE CEMENT
SILICATE CEMENT
ZINC SILICOPHOSPHATE CEMENT
ZINC POLYCARBOXYLATE CEMENT
ZINC OXIDE EUGENOL CEMENT
NON-EUGENOL CEMENT
GLASS IONOMER CEMENT
RESIN CEMENTS
REFERENCES
2

3. INTRODUCTION
Cementisdefinedasasubstancethathardenstoactasabase,
liner,fillingmaterial,oradhesivetobinddevicesandprostheses
totoothstructureortoeachother.
-Phillips’ science of dental materials 11
th
edition
Dentalcementsaregenerallyinorganic,nonmetallicsubstances
thathardentoactasabase,liner,orrestorationorasan
adhesivetobinddevicesorprosthesistotoothstructure.
Dentalcementsarecommonlypowder-liquidsystemsthatsetvia
acid-basereactionorchelation.Theyareusedforrestorative,
endodontic,orthodontic,periodonticaswellassurgical
procedures.
Last2decadeshaveseenavarietyofchangesinthedental
cementcompositionandalsointroductionofneweradvanced
biocompatiblematerials.
3

4. CLASSIFICATION
Based on the INGREDIENTS
4

5. According to Phillip’s
5

6. 6

7. According to Craig:
7

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
9

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
10

11. COMPOSITION
11

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
12

13. SETTING REACTION
Phosphoric acid attacks the surface of the particles
Releases zinc ions into the liquid
Aluminium formscomplexes 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)
13

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%
14

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
15

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.
16

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
17

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
18

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
19

20. Composition
Powder
Silica(40%)
Alumina(30%)
Cryolite(19%)
Calcium fluoride
Sodium fluoride
Calcium phosphate
Liquid
Phosphoric acid(52%)
Water(40%)
Aluminum
phosphate(2%)
Zinc phosphate/
magnesium phophate
20

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%
21

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.
22

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
23

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
24

25. COMPOSITION
25

26. PROPERTIES
BIOLOGIC EFFECT-
Prolonged low pH (4-5)
Pulpal protection necessary
Anticariogenic –fluoride release
26

27. 27

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)
28

29. COMPOSITION
29

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.
30

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
31

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
32

33. BIOLOGIC EFFECTS-
Good biocompatibility
Low intrinsic toxicity
Rapid rise in pH towards neutrality
Fluoride release
33

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
34

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
35

36. COMPOSITION
36

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
37

38. PROPERTIES
38

39. BIOLOGIC EFFECTS
Bacteriostatic
Obtundantproperty
pH (6.6 –8) : mild pulpalresponse
Volumetric shrinkage : 0.9%
When in direct contact with connective tissues, it is an irritant
Reparative dentin formation
39

40. REINFORCED ZINC OXIDE
EUGENOL CEMENT
To overcome the shortcomings of the zinc oxide cements
APPLICATION
Cementing crowns and FPD
Cavity liner
Base materials
Provisional restoration
40

41. COMPOSITION
41

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
42

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
43

44. 44

45. EBA MODIFIED ZINC OXIDE
EUGENOL CEMENT
APPLICATION
Cementation of inlays, crowns, FPD’s and for provisional restoration
Base / lining material
COMPOSITION
45

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
46

47. PROPERTIES
BIOLOGIC EFFECTS-
•Similar to ZnO eugenol cement
47
Bacteriostatic
Obtundant property

48. NONEUGENOL CEMENTS
EBA-ethoxy benzoic acid
Advantages over ZOE:
No irritation to soft tissue
Compatible with acrylic resin materials
48

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
49

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.
50

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
51

52. COMPOSITION
POWDER
Glass is ground into powder particles of 15-50micro meter
52

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
53

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.
54

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.
55

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
56

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
57

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
58

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.
59

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
60

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.
61

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.
62

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.
63

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
64

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.
65

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.
66

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.
67

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.
68

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.
69

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.
70

71. CALCIUM HYDROXIDE
Hermann –1920
Useful water setting cement which has osteoconductive
and osteoinductive property
As a pulpcapping agent facilitatesformation of reparative
dentin–alkaline pH, antibacterial and protein lyzing
property.
TYPES:
Non setting (pH : 11 –13) –intracanal medicament
Setting (pH : 9 –10) –cavity liner
71

72. APPLICATION
Liners in deep cavity preparations
Intracanal medicaments
Direct and indirect pulp capping
Apexification procedures
COMPOSITION
2 Pastes –Base and Catalyst
72

73. SETTING REACTION
Calcium hydroxide reacts withthe 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
73

74. PROPERTIES
74

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 induceschemical 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 enzymessuchasalkaline mineralization
phosphatase which is responsible for mineralisation
Free calcium hydroxide helps in menaralisation of carious
dentin
75

76. CALCIUM HYDROXIDE
76

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.

77

78. REFERENCE:
M.A Marzouk Operative Dentistry
Phillips Science of Dental Materials.-10th edition
CRAIG’S Restorative Dental Materials-12th edition
Skinner’s science of dental materials(Phillips) 8th edition
78

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