Zinc phosphate cement Zinc polycarboxylate cement Zinc oxide eugenol cement

1. Cements
(Zinc Phosphate
Zinc Polycarboxylate
&
Zinc Oxide Eugenol)
PRESENTED BY:
ARPIT VIRADIYA
GUIDED BY:
DR.SANDEEP METGUD
DR.DEEPALI AGRAWAL

2. Contents
• Zinc Phosphate Cement
• Introduction
• Composition
• Setting Reaction
• Working & Setting
Time
• Physical Properties
• Retention
• Biological Properties
• Manipulation
• Applications
• Zinc Polycarboxylate
Cement
• Introduction
• Composition
• Chemical Reaction
• Bonding to Tooth
Structure
• Working & Setting
Time
• Mechanical Properties
• Biological
Consideration
• Manipulation
• Applications
• Zinc Oxide Eugenol Cement
• Introduction
• Classification
• Composition
• Setting Reaction
• Manipulation
• Physical Properties
• Biological Properties
• Polymer reinforced
ZOE
• EBA and Alumina
reinforced ZOE
• Non Eugenol ZOE
• Summary & Conclusin
• References

3. Zinc phosphate cement

4. Introduction
• Oldest of the luting cement
• Longest clinical track record
• Serves as a standard with which newer materials can
be compared
• Supplied as a powder and liquid.

5. Composition
 POWDER
 Zinc oxide - 90%
 Magnesium oxide – 9-10 %
 Bismuth trioxide, Barium oxide – traces
sintered at temperatures between 1000deg Celsius and
1400 deg Celsius -> cake -> fine powder
particle size -> setting time

6.  Liquid
 Phosphoric acid
 Water
 Aluminium Phosphate
 Zinc Phosphate (some times)
Water controls the ionization reaction of acid - in turn
influence the rate of acid base reaction
Acid content of the liquid - 33% approximately.

7. SETTING REACTION
 When the powder is mixed with liquid , the
phosphoric acid attacks the surface of the particles -
releases zinc ions into the liquid – aluminium, which
already forms a complex with the phosphoric acid ,
reacts with zinc - zinc alumino phosphate gel on the
surface of the remaining portions of the particles.
 Water is critical to the reaction.
 ZnO + H3PO4
 Zn3(Po4)2 + H2O

8.  Changes in composition and reaction rates might
occur due to degradation of the liquid or water
evaporation from the liquid
 Liquid degradation effects are exhibited as clouding of
the liquid
 Loss of water from acid increases the setting time

9. Working and Setting Times
 Mixing time of 1.5 – 2 mins
 Setting time – 2.5 – 8 mins
 The following procedures can extend the setting time
 Reducing P/L ratio
 Mixing in increments
 Prolonging the spatulation of last increment.
 Cooling the glass slab

10. Physical Properties
 Compressive strength :104MPa
 Tensile strength:5.5MPa
 Thermal conductivity : 3.11 mcal.cm/cm2.sec.K
 Low water solubility 0.04wt%
 More soluble in dilute organic acids
 Modulus of elasticity:13.7GPa
 Quiet stiff & resistant to elastic deformation
Loss/Gain water content compressive tensile strength.

11. Retention
Doesn’t involve reaction with surrounding hard
tissue/restorative material
No chemical interactions
Mechanical bonding at interfaces

12. Biological Properties
 Acidity of cement is quite high during the time of
application - presence of phosphoric acid
2 min after the start of mixing , Ph is 2
increases rapidly
reaches about 5.5 in 24 hrs
 Pulpal damage can occur during first few hours.
 High heat production during setting of the cement can
also cause pulpal injury.

13. Manipulation
 Incorporate powder - liquid
 Recommended p/l ratio – 1.4gm - 0.5ml
 A cool mixing slab prolongs the working and setting
time
Liquid dispensed onto the slab
evaporation

14.  Powder -several increments
 spatulated : 15 – 20 secs
 smaller quantities - first few
increments – working - setting time.
 middle of the mixing – larger amounts
of powder– to further saturate the
liquid with newly formed zinc
phosphate.
 Finally , smaller increments are added
– so that the desired ultimate
consistency of the cement is not
exceeded
 begins & ends with small increments

15. Applications
 Luting permanent restorations
 Bases
 Cementation of orthodontic bands
 Provisional restoration

16. Zinc Polycarboxylate Cement

17. Introduction
 Zinc polyacrylate cement
 First - adhesive bond to tooth structure.
 Supplied as
 Powder and liquid

18. Composition
 Powder
Zinc oxide – 72% Basic ingredient
Magnesium oxide – 7% Modifier , aids in sintering
Other oxides like bismuth
and aluminium
Stannous fluoride
Increase strength, modifies
setting time, imparts
anticariogenic properties

19.  Liquid
 Liqueous solution of polyacrylic acid (32-48%)
Or
 Copolymer of acrylic acid with other unsaturated
carboxylic acids (itaconic , maleic , tricarballylic acids)
 Molecular weight – 25,000 – 50,000

20. Chemical reaction
 When acid comes in contact with powder , acid reacts
and releases zinc, magnesium, and tin ions
 They bond to the polymer chain , through the carboxyl
groups
 These ions also react with carboxylic groups of
adjacent poly acid chains
 Cross inked salts are formed

21. Bonding to tooth structure
 Poly acrylic acid reacts with calcium ions via carboxyl
groups on the surface of enamel or dentin.
 Bond strength greater on enamel than dentin.
 Enamel 3.4-13.1MPA Dentin 2.07MPA

22. Working and Setting time
 Working time : 2.5 min
 Setting time : 6-9 min
 Lowering the temperature of chemical reaction can
increase the setting time.

23. Mechanical Properties
 Comprssive strength : 55-67 Mpa
 Tensile strength : 2.4-4.4 Gpa
 Modules of elasticity is lower then zinc phosphate
cement 5.1GPa
 More soluble than zinc phosphate cement 0.06%
 More soluble in organic acids.
 Not as brittle as zinc phosphate cement
 Excess removal is difficult.

24. Biological Consideration
 Pulpal response termed as mild
 Ph of liquid is 1- 1.7
 Freshly mixed cement – 3-4
 After 24 hrs – 5 -6

25. Manipulation
 A cooled glass slab / powder
 1.5 parts of powder to 1 part of liquid by weight
 Liquid not dispensed , before the start
 Loss of water, increases viscosity
 Powder is rapidly incorporated into the liquid in large
quantities
 Mixing time is with in 30 – 60 sec ,with half to all of
powder incorporated at once to provide the maximum
length of working time
 Surface - glossy , acid present to provide sufficient
carboxylic groups to bond.

26. Glossy Appearance
Dull Appearance

27. Applications
 Primarily for luting permanent restorations
 As bases and liners
 Cementation in orthodontic treatment

28. Zinc Oxide Eugenol Cement

29. Introduction
 These cements have been extensively used in dentistry
since 1890’ s
 They are least irritant of all dental cements
 Have an obtundant or sedative effect
 Compatible with the hard and soft tissues of the
mouth

30. Classification
 Type 1 ZOE – for temporary cementation
 Type 2 ZOE – permanent cementation
 Type 3 ZOE – temporary filling material , thermal
insulation
 Type 4 ZOE – Cavity liners

31. Composition
 Powder
Zinc oxide – 69% Principle ingredient
White rosin –
29.3%
Reduce brittleness
Zinc stearate – 1% Accelerator , plasticizer
Zinc acetate –
0.7%
Accelerator , improves strength
Magnesium oxide Added in some powders

32.  Liquid:
 Eugenol – 85% - reacts with zinc oxide
 Olive oil – 15% - plasticizer

33. Setting reaction
 First , hydrolysis of zinc oxide to its hydroxide
 Water is essential for reaction to proceed
 reaction is a acid base one,
 Zinc hydroxide combines with eugenol to form a chelate
ZnO + H2O → Zn(OH)2
 ZINC EUGENOLATE
 Forms an amorphous gel, which later tends to crystallize.
 Structure : particles of unreacted zinc oxide embedded in a
matrix of zinc eugenolate
Zn(OH)2 + 2HE → ZnE2 + 2H2O

34. Manipulation
 p/l ratio 4:1 to 6:1 by wt
 the bulk - incorporated into the liquid -spatulated
thoroughly in a circular motion - a stiff bladed spatula
 Small increments - until the mix is complete –
consistency

36.  Setting time - 4-10 mins
 Complete setting reaction between zinc oxide and eugenol
takes about 12 hrs
Factors affecting setting time:
 Particle size – smaller particle size, set faster
 Accelerators – alcohol , glacial acetic acid , and small
amounts of water
 Retarders – glycol, glycerine
 Temperature – high temperature , accelerate setting
 Powder/ liquid ratio – higher the ratio, faster the set

37. Physical properties
 Relatively week cements
 Compressive strength : Ranges from 3-4mpa to 50-
55mpa
 Tensile strength : 0.32 to 5.8mpa
 Modules of elasticity : 0.22 – 5.4 mpa
 Excellent thermal conductivity
 Solubility of the set cement is high - disintegrate in
oral fluids - Solubility is reduced by increasing p/l
ratio

38. Biological properties
 Least irritating of all dental cements
 Ph is 6.6 – 8
 Pulp response is termed as mild
 They inhibit the growth of bacteria , have an anodyne
or soothing effect on pulp , in deep cavities, hence
reduces pain

39. Modified Materials
 Polymer reinforced ZOE
 introduced in an effort to increase the
mechanical properties of zoe.
 Contains Zinc Oxide and finely divided
natural or synthetic resin like poly methyl
methacrylate resulting in good strength,
improved abrasion resistance and
increased toughness
 Luting agent, Base, temporary filling
material and as a cavity liner.

40.  EBA and alumina modified ZOE cement
 Powder :
 ZnO 70%
 Alumina 30%
 Liquid:
 EBA 62.5%
 Eugenol 37.5%
Properties are better than unmodified zoe
Compressive strength increased 55 mpa
Tensile strength – 4.1mpa
Modulus of elasticity – 2.5 gpa
Solubility and disintegration – 0.05% wt

41.  Non eugenol Zinc Oxide cement
 Suitabe for patients sensitive to eugenol.
 Eugenol acts as an inhibitor for free redical
polymerized materials

42.  ZOE based periodontal pack
 It protects the wound from
mechanical trauma and
stabilize the surgical site.
 It also prevents post operative
hemorrhage and infection;
decreases tooth
hypersensitivity in first few
hours after suurgery.

43. Conclusion
 Though cements are used in small quantities in oral
cavity, it should be used with at most care, as it is very
important. There are innumerable cements present
with different properties, one should know all the
properties to use it in order to give a successful
restoration to the patient

44. References
 PHILLIPS , SCIENCE OF DENTAL MATERIALS
 11TH EDITION
 CRAIG’ S RESTORAIVE DENTAL MATERIALS
 12TH EDITION
 STURDEVANTS ART AND SCIENCE OF OPERATIVE
DENTISTRY
 5TH EDITION
 DENTAL CLINICS OF NORTH AMERICA
 JULY 2007 51:3 SAUNDERS
 DENTAL CLINICS OF NORTH AMERICA
 OCTOBER 1983 27:4 SAUNDERS

45. THANK YOU