dental cements

2. Introduction
Def: A dental cement is a biomaterial composed
of but not limited to an acid and a basic
component that react to set into a rigid
material.
• Dental cements may also be polymeric i.e. set
through polymerization reactions.
2

3. 3 main Categories
3

4. Applications of Dental Cements
• Dental Cements have both temporary and
permanent applications:
i. Luting
ii. Lining
iii. Cementing Orthodontic appliances
iv. Fissure sealants
v. Root filling materials
vi. Temporary fillings
vii. Permanent fillings
viii. Core build-up
4

5. Dental Cements
1. Silicate Cements
2. Zinc phosphate Cement
3. Zinc polycarboxylate Cement
4. Glass Ionomer Cement
5. Zinc oxide Eugenol Cements
6. Calcium hydroxide Cement
7. Resin Cements
8. Mineral Trioxide Aggregate
5

6. ZINC PHOSPHATE CEMENT
6

7. Powder Liquid
• Zinc oxide
• Magnesium oxide
• Other oxides &
fluorides
• Phosphoric acid (H3PO4)
• Water (30-40%)
• Buffering agents -- Zinc oxide, zinc
hydroxide
Presentation forms
Mixing
on thick, cool glass slab using stainless steel spatula
powder is added to the liquid in small increments
Mixing over a wide area
• Thin mix  for cementation
• Thick mix  for cavity base /temp. filling
7

8. Zinc phosphate cement
Powder Liquid
•Zinc oxide-90%
•Magnesium oxide-
8.2%
•Other oxides
(Bi2O3)
Silica
phosphoric acid
water
aluminum phosphate
zinc phosphate
8

9. 9

10. How it sets?
Through a Fast , exothermic acid-base Rx (Crystallisation)
ZnO + H3PO4  Zn3(Po4)2 + H2O
Set material
matrix of zinc phosphate salt+ dispersed non-reacted zinc oxide particles
Controlling the Rx speed (setting time)
1. ↓ Powder particle size   reaction
2.  Temperature   reaction
3. ↓ Buffers   reaction
4.  P/L ratio   reaction
5.  Mixing rate (speed or time)   reaction
6.  Acid concentration   reaction
10

11. 1. Biological Characteristics
• Pulp irritant -- fresh mix is highly acidic (pH 1.6-3.6)
-- Ca(OH)2 liner is needed in deep cavities
-- Thin mix is more irritant than the thick mix
-- Set material becomes neutral in 48 hrs
• Low thermal diffusivity -- insulate thermal and electrical irritations
Material’s Characteristics (BMIECP)
2. Mechanical Characteristics
• Stronger than ZOE and weaker than GI
-- withstand amalgam’s condensation forces (cavity bases)
-- could withstand masticatory forces ( permanent cementation /temp filling)
3. Interfacial Characteristics
• Mechanically-retained -- to both tooth and restorations’ surfaces
• Film thickness similar to that of zinc polycarboxylate cement (15μm)
11

12. 4. Esthetic Characteristics
• Opaque – not used to lute translucent ceramic restorations
5. Chemical Characteristics
• Water soluble -- dissolves in oral saliva
-- thin mix dissolves more than the thick mix
6. Practicability
• Material is successfully used for a long time
• Needs well-trained operator due to its short S.T.
• precautions –
1. Liquid bottle should be tightly closed all the time
2. Liquid with cloudy appearance should be discarded
3. Shake the powder bottle before dispensing the correct ratio
4. never use powder of other cements (e.g. ZOE…) or of other manufacturer
12

13. 13

14. ZINC POLYCARBOXYLATE CEMENT
14

15. 1. Powder Liquid
• Zinc oxide
• Magnesium oxide
• Flourides
• Poly-acrylic acid (30-40%)
• Water
2. Powder in a
single bottle
water settable material
Freeze dried acid is blended with the powder
3. Capsules
Presentation forms
15

16. Mixing
On a glass slab using stainless steel spatula
PAA is viscous and needs more effort during material’s mixing
• Thin mix ( P/L ratio 1.5:1) for cementation
• Thick mix ( P/L ratio 2.5:1) for cavity base /temp. filling
How it sets?
Through a acid-base Rx
ZnO + PAA  Zn-polyacarylate + H2O
Set material
matrix of zinc polyacrylate salt+ dispersed non-reacted zinc oxide particles
16

17. 17

18. 1. Biological Characteristics
• Pulp irritant -- fresh mix is acidic But less than zinc phosphate cement is
-- Ca(OH)2 liner is needed in deep cavities
-- Thin mix is more irritant than the thick one
-- Set material becomes neutral in 48 hrs
• Low thermal diffusivity -- insulate thermal and electrical irritations
Material’s Characteristics (BMIECP)
2. Mechanical Characteristics
• Its strength is comparable to that of zinc phosphate cement
-- withstand amalgam’s condensation forces (cavity bases)
-- could withstand masticatory forces ( permanent cementation /temp filling)
3. Interfacial Characteristics
• Chemically adhere -- to the tooth and base metal restorations
• Film thickness similar to that of zinc phosphate cement (15μm)
18

19. 4. Esthetic Characteristics
• Opaque – not used to lute translucent ceramic restorations
5. Chemical Characteristics
• More soluble in water than zinc phosphate cement
-- thin mix dissolves more than the thick mix
6. Practicability
• Viscous liquid make the mixing process a little bit difficult
• All metallic instruments should be cleaned up while the cement still unset
• To achieve better bonding
1. Tooth surface should be cleaned and dried from saliva
2. Mixed cement should be applied to tooth structure as fresh as possible
19

20. Applications
1. Final cementation 2.Cavity base
3. Temporary filling 4. Cementation of orthodontic bands
5. Dentin building-up
20

21. ZINC OXIDE EUGENOL (ZOE) CEMENT
21

22. Presentation forms
Powder Liquid
• Zinc oxide
• Magnesium oxide
• Zinc Acetate- Accelerator
• Eugenol
• Olive oils
• Acetic acid- Accelerator
Two paste system
(Base & Catalyst)
Eugenol-Containing
Eugenol-Free
Single paste – sets in contact with water
22

23. 23

24. How it sets? via acid-base Rx (Chelation)
• ZnO + H2O  Zn(OH)2 (1)
• Zn(OH)2 + E  Zinc Eugenolate (2)
Mixing
on either paper pad or glass slab using a stainless steel spatula at high P/L ratio (4 :1)
• Thin mix  for temp. cementation
• Thick mix  for temp. filling
Set material
Matrix of zinc eugenolate (chelate) + Dispersed non-reacted Zinc oxide particles
• Presence of water is essential – Saliva could help
• Zinc acetate dissolves faster in water  zinc hydroxide
24

25. Controlling the Rx speed (setting time)
1. ↓ Powder particle size   reaction
2.  Temperature   reaction
3.  Accelerators   reaction
4.  P/L ratio   reaction
5.  Mixing rate (speed or time)   reaction
25

26. 1. Biological Characteristics
• Bacteriostatic -- kills bacteria of carious cavities
• Low thermal diffusivity -- insulate thermal and electrical irritations
• Obtundent effect -- reduces the pulpal pain
• High sealing ability -- minimize the leakage in temp. restored cavities
Material’s Characteristics (BMIECP)
26

27. 2. Mechanical Characteristics
• Weak cement -- could not withstand either masticatory forces
-- could not withstand amalgam’s condensation forces
4. Esthetic Characteristics
• Opaque – not used to lute translucent ceramic restorations
3. Interfacial Characteristics
• Mechanically-retained -- to both tooth and restorations’ surfaces
-- adapt well to cavity walls
27

28. 5. Chemical Characteristics
• Water soluable -- dissolves in oral saliva
• Eluted Eugenol -- changes the color of overlying composite restoratives
-- retard the polymerization of overlying composite restoratives
-- swallowed E causes gastric troubles
6. Practicability
• Easily mixed – no special precautions but – it is better to mix it in thick consistency
28

29. Applications
1. Temporary cementation 2. Temporary filling
3. Cavity liner 4. Indirect pulp capping
5. Endodontic sealer 6. Surgical packs
29

30. CALCIUM HYDROXIDE
30

31. Presentation forms
Ca(OH)2 powder
Single paste – methyl cellulose- sets in air
Light-cured Ca(OH)2 paste – resin matrix
Two paste -- the only sets via an acid-base Rx
Base Catalyst
• Calcium hydroxide
• Zinc oxide
• Zinc Acetate- Accelerator
• Liquid vehicle
• di-salicylate,
• Radio-opacifers,
• Fillers
31

32. composition
Acidic paste
• Alkyl salicylate (iso-butyl salicylate or 1-methyl triethylene
salicylate)
• Inert fillers – titanium oxide 12-14%
• Radiopacifer – barium sulphate 32-35%
• Calcium tungstate or calcium sulphate 14-15%
32

33. Basic paste
• Calcium hydroxide 50-60%
• Zinc oxide 10%
• Zinc stearate 0.5%
• Ethylene toluene sulphonamides and paraffin oil 39.5%
33

34. Classification
Based on the setting time
• Fast setting
• Controlled setting
• Slow setting
• No setting
34

35. – Based on mechanism of setting
– Self curing – dycal
– Light curing – prisma VLC dycal
– Based on vehicle used
– Aqueous vehicle
Eg. Water, saline dental anesthetic, ringers solution, aqueous
suspension of methylcellulose.
– Viscous vehicle – ex. glycerine, polyethylene glycol and
propylene glycol.
– Oily vehicles – Olive oil, oleic acid, linoleic and isosteric acid.
35

36. Mode of supply
• Can be supplied in powder form – powder
can be mixed with distilled water, saline
solution to form a thick paste and applied
as such.
• Can be supplied as two paste system, one
base paste another catalyst paste.
• Can be supplied as single paste (visible
light).
36

37. 1. Biological Characteristics --- related to material’s alkalinity (pH= 11-13)
• Bacteriostatic -- kills bacteria of carious cavities
• Neutralizes the acids produced by the cariogenic bacteria
• Help differentiate pulpal stem cells -- reparative dentin stimulator
Material’s Characteristics (BMIECP)
2. Mechanical Characteristics
• Weak cement -- could not withstand amalgam’s condensation forces
4. Esthetic Characteristics
• Opaque – not used to lute translucent ceramic restorations
3. Interfacial Characteristics
• Mechanically-retained -- does not adhere to the tooth structure
5. Chemical Characteristics
• Quite soluble -- dissolves in liquids even under leaked restorations
37

38. Applications
1. Direct & indirect pulp capping 4. temp. endodontic filling
2. Cavity liner 5. Temporary cementation
2. Endodontic sealer 6. pulpotomy
38

39. INDIRECT PULP TREATMENT
• Indirect pulp treatment is defined as “the application of a
medicament over a thin layer of remaining carious dentin, after
deep excavation, with no exposure of the pulp”
• Carious dentin actually consists of two layers having different
ultramicroscopic and chemical structures. The outer carious layer
is irreversibly denatured, infected and incapable of being
remineralized and hence should be removed. The inner carious
layer is reversibly denatured but not infected and is capable of
being remineralized
39

40. The technique:
• carious dentin is removed with a sharp spoon excavator and a hard set
calcium hydroxide dressing is given to cover the remaining affected dentin.
• The remainder of the cavity is then filled with a reinforced zinc oxide
eugenol cement or GIC. This sealed cavity is not disturbed for a minimum
of 6-8 weeks.
• At the next appointment radiographs of the affected tooth are taken to assess
the presence of reparative dentin. The temporary filling with calcium
hydroxide is removed carefully.
• The reparative dentin layer is not disturbed. Over this another fresh
application of calcium hydroxide is given over which a permanent filling is
done with a suitable base.
40

41. CALCIUM HYDROXIDE AS A PULP
CAPPING AGENT
• Calcium hydroxide is generally accepted as the material of
choice for pulp capping.
• Histologically there is a complete dentinal bridging with
healthy radicular pulp under calcium hydroxide dressings.
• When calcium hydroxide is applied directly to pulp tissue
there is necrosis of adjacent pulp tissue and an inflammation
of contiguous tissue.
• Dentinal bridge formation occurs at the junction of necrotic
tissue and vital inflamed tissue. Beneath the region of
necrosis, cells of underlying pulp tissue differentiate into
odontoblasts and elaborate dentin matrix.
41

42. •Three main calcium hydroxide products are: Pulpadent, Dycal,
Hydrex.
•Pulpadent paste is considered to be most capable of stimulating
early bridge formation.
•Hydrex has been considered that fast capable of forming a bridge.
•The action of calcium hydroxide to form a dentin bridge appears
to be a result of the low grade irritation in the underlying pulp
tissue after application.
42

43. CALCIUM HYDROXIDE IN PULPOTOMY
• It is the most recommended pulpotomy medicament for
pulpally involved vital young permanent tooth with
incomplete apices.
• It is acceptable because it promoted reparative dentin
bridge formation and thus radicular pulp vitality is
maintained to allow uninterrupted physiological
completion of root and root canals
43

44. Three histologic zones under calcium hydroxide in 4-9 days:
1. Coagulation necrosis.
2. Deep staining areas with varied osteodentin.
3. Relatively normal pulp tissue, slightly hyperemic, underlying an
odontoblastic layer.
Histologically pulp tissue adjacent to calcium hydroxide
was first necrotized by the high pH of calcium hydroxide.
This necrosis was accompanied by the acute
inflammatory changes in the underlying tissue.
After 04 weeks a new odontoblastic layer and eventually
a bridge of dentin developed.
44

45. • Internal resorption may result from overstimulation of the
primary pulp by the highly alkaline calcium hydroxide.
• This alkaline induced overstimulation could cause metaplasia
within the pulp tissue, leading to formation of odontoclasts.
• Also undetected microleakage could allow large numbers of
bacteria to overwhelm the pulp and nullify the beneficial
effects of calcium hydroxide
45

46. • Calcium hydroxide incorporated in a methylcellulose
base such as pulpdent, showed earlier and more
consistent bridging.
• At present calcium hydroxide pulpotomy technique
cannot be generally recommended for primary teeth.
• Recommended agent for carious and traumatic
exposures in young permanent teeth, particularly with
incomplete closure.
46

47. CALCIUM HYDROXIDE IN WEEPING
CANALS
• Sometimes a tooth undergoing root canal treatment shows constant clear or
reddish exudate associated with periapical radiolucency.
• Tooth can be asymptomatic or tender on percussion. When opened in next
appointment, exudates stops but it again reappear in next appointment, this is
known as “weeping canal”.
• For such teeth dry the canals with sterile absorbent paper points and place
calcium hydroxide in canal.
• It happens because pH of periapical tissues is acidic in weeping stage which
gets converted into basic pH by calcium hydroxide.
47

48. • Calcium hydroxide can act even in the presence of blood and other tissue
exudates.
• It has a definite characteristics of producing ca ions, resulting in less
leakage at the capillary junction.
• It causes contraction of the pericapillary sphincters, thus resulting in less
plasma outflow. Hence, it is the material of choice for weeping canals.
48

49. GLASS IONOMER CEMENT
49

50. CLASSIFICATION
I. For luting
II. For restoration
III. For liner & bases
IV. Fissure & sealent
V. As Orthodontic cement
VI. For core build up
Type II.1 Restorative esthetic
Type II.2 Restorative reinforced
Type
Type
Type
Type
Type
Type
50

51. COMPOSITION
Powder :-
Acid soluble calcium fluroalumino silicate glass.
Silica - 41.9%
Alumina - 28.6%
Aluminum fluoride - 1.6%
Calcium fluoride - 15.7%
Sodium fluoride - 9.3%
Aluminum phosphate - 3.8%
Fluoride portion act as ceramic flux.
Strontium, Barium or zinc oxide provide radio opacity.
51

52. Liquid :-
1.Polyacrylic acid in the form co-polymer with
itaconic acid & malice acid .
2.Tartaric acid: improves handling characteristic
& increase working time.
3.Water : Medium of reaction & hydrates the
reaction products
52

53. SETTING REACTION
When the powder &
liquid are mixed,
Surface of glass
particles are attacked
by acid. then Ca, Al,
sodium, & fluoride
ions are leached into
aqueous medium.
53

54. Water plays an important role in structure of
cement.
After hardening, fresh cement is extremely prone
to the cracking & crazing, due to drying of
loosely bound water .
Hence these cements must be protected by
application of varnish.
54

55. SETTING TIME
• Type I 4 - 5 minutes
• Type II 7 minutes
55

56. PROPERTIES
• Compressive strength - 150 mpa
• Tensile strength - 6.6 mpa.
• Hardness - 49 mpa.
56

57. Solubility & Disintegration:-
• Initial solubility is high due to leaching of
intermediate products.
• The complete setting reaction takes place in 24
hrs, cement should be protected from saliva
during this period.
57

58. Adhesion :-
☻Glass ionomer cement bonds chemically to the tooth
structure.
☻Bonding is due to reaction occur between carboxyl group of
polyacrylic acid & calcium of hydroxyl apatite.
☻Bonding with enamel is higher than that of dentin ,due to
greater inorganic content.
Esthetics :-
GIC is tooth coloured material & available in different
shades.
Inferior to composites.
They lack translucency & rough surface texture.
Potential for discolouration & staining.
58

59. Biocompatibilty :-
• Pulpal response to glass ionomer cement is favorable.
• Pulpal response is mild due to
- High buffering capacity of hydroxy apatite.
- Large molecular weight of the polyacrylic
acid ,which prevents entry into dentinal tubules.
Anticariogenic properties :-
•Fluoride is released from glass ionomer at the time of
mixing & lies with in matrix. Fluoride can be released out
without affecting the physical properties of cement.
59

60. Initial release is high. But declines after 3
months.
After this, fluoride release continuous for a
long period.
Fluoride can also be taken up into the
cement during topical fluoride treatment
and released again ,thus GIC act as fluoride
reservoir.
60

61. MANIPULATION
1.Preparation of tooth surface :-
The enamel & dentin are first cleaned with pumice slurry
followed by swabbing with polyacrylic acid for 5 sec.
After conditioning & rinsing ,tooth surface should isolate
& dry.
2.Proportioning & mixing :-
 Powder & liquid ratio is 3:1 by wt. Powder & liquid is
dispensed just prior to mixing.
 First increment is incorporated rapidly to produce a
homogenous milky consistency.
 Mixing done in folding method to preserves gel structure.
 Finished mix should have a glossy surface.
61

62. 3. Protection of cement during setting :-
• Glass ionomer cement is extremely sensitive to
air & water during setting.
• Immediately after placement into cavity,
preshaped matrix is applied to it.
4. Finishing :-
Excess material should be trimmed from margins.
Hand instruments are preferred to rotary tools to
avoid ditching.
Further finishing is done after 24hrs.
62

63. 5.Protection of cement after setting :-
• Before dismissing the patient ,restoration is
again coated with the protective agent to protect
trimmed area.
• Failure to protect for first 24hrs results in
weaken cement.
63

64. Advantages:-
♣ Inherent adhesion to the tooth surface.
♣ Good marginal seal.
♣ Anticariogenic property.
♣ Biocompatibilty
♣ Minimal cavity preparation required.
Disadvantages:-
♦ Low fracture resistance.
♦ Low wear resistance.
♦ Water sensitive during setting phase .
♦ Less esthetic compared to composite.
64

65. Uses :-
1. Anterior esthetic restoration material for class
III & V restorations.
2. For luting.
3. For core build up.
4. For eroded area .
5. For atraumatic restorative treatment.
6. As an orthodontic bracket adhesive.
7. As restoration for deciduous teeth.
8. Used in lamination/ Sandwich technique.
65

66. SANDWICH TECHNIQUE
Devolped by Mclean,
To combine the beneficial properties of
GIC & composite.
66

67. Clinical steps:-
After cavity preparation,
condition the cavity to
develop good adhesion with
GIC.
Place Type III GIC into
prepared cavity.
After setting, etch the
enamel & GIC with
orthophosphoric acid for 15
seconds.
This will improve
micromechanical bond to
composite resin.
Apply a thin layer of low
viscosity enamel bonding
agent & finally place the
composite resin over GIC &
light cure it.
67

68. ADVANTAGES:-
♣ Polymerisation shrinkage is less,due to reduced
bulk of composite.
♣ Favorable pulpal response.
♣ Chemical bond to the tooth.
♣ Anticariogenic property.
♣ Better strength,finishing,esthetics of overlying
composite resin.
68

69. MODIFICATIONS
1.Water settable glass ionomer cement :-
• Liquid is delivered in a freeze dried form ,which is
incorporated into the powder.
• Liquid used is clean water.
2.Resin modified glass ionomer cement :-
Powder component consist of ion leachable fluroalumino
silicate glass particles & initator for light curing.
Liquid component consist of water & poly acrylic acid
with methacrylate & hydroxyl ethyl methacrylate
monomer.
69

70. 3.Metal modified glass ionomer cement:-
• Glass ionomer have been modified by addition of filler
particles ,to improve strength ,fracture toughness &
resistance to wear.
Silver alloy admix / miracle mix:-
• This is made by mixing of spherical silver amalgam
alloy powder with glass ionomer powder.
Cerment:-
• Bonding of silver particles to glass ionomer particles by
fusion through high temperature sintering.
70

71. 4.Compomer :-
Compomer is a composite resin that uses an
ionomer glass which is the major component of
glass ionomer as the filler.
Small quantity of dehydrated polyalkenoic acid
incorporated with filler particles,
Setting reaction is light activated.
Adhesive system used with compomer is based on
acid etch found with all composite resin.
71