DLA 1201, exam 1

1. Dental Cements
ZINC OXIDE EUGENOL
ZINC PHOSPHATE
ZINC POLYCARBOXYLATE
GLASS IONOMER CEMENTS
RESIN-BASED CEMENTS
PERIODONTAL DRESSINGS
CALCIUM HYDROXIDE
CAVITY VARNISH

2. Pulpal Protection
 Cavity Varnish
 Acts as a protective barrier between preparation and restoration
 Varnish formulations are solutions of natural resins (copal) or synthetic resins
dissolved in a solvent, such as alcohol or chloroform.
 Varnish is applied in two-three layers over the surface of the preparation
 The solution is placed in a thin film, allowing evaporation of the solvent to
occur for 5-15 seconds before application of the second layer.
 The remaining resin protects the pulp by sealing the tubules from
penetration of irritating chemicals found in some restorative materials and
luting cements.
Luting: primary consistency, used to cement two components together

3. Copal Varnish
 Brand name: Copalite
 Is thought to reduce the amount of microleakage and
staining at the restoration/tooth interface.
Interface: the space between the walls of the preparation and the
restoration
 Not widely used today
 They were extensively used under amalgam restorations
 They have been replaced by dentin bonding agents, since they
seal enamel and dentinal tubules.

4. Low-Strength Base/Liner
 Example: Calcium Hydroxide
Brand name: Dycal
Used when dentin no longer covers the pulp
When close or very small exposures of pulp are suspected, this
material is used as an indirect or direct pulp-capping agent
Alkaline pH of 9-11
Stimulates secondary dentin when in direct contact with the
pulp
Provides a barrier between pulp and restoration

5. Calcium Hydroxide
Has some antimicrobial and thermal
insulating properties
Provides minimal strength to support
Under amalgam restorations, Dycal
slowly leaches out over time.

6. Calcium Hydroxide-- Dycal
 Mixing time: 10 seconds
 Setting time: 2-2.5 minutes
 Procedure:
 Dispense equal portions of catalyst
and base paste onto mixing pad
 Mix pastes together using small
spatula or cavity liner applicator
 Mix until material is uniform in color
 Gather material together and place
on clean portion of the pad
https://youtu.be/czrBP-qrbYc

7. Zinc Oxide Eugenol
 ZOE
 Powder/liquid or paste/paste systems
 Used for:
 Temporary/provisional cementation
 Temporary and intermediate restorations
 High- and low-strength bases
 root canal sealer
 Periodontal dressings

8. Zinc Oxide Eugenol
 Principal Ingredient: zinc oxide
 Eugenol: distinct smell of cloves
 Derivative of oil of cloves
 Eugenol is known for its sedative effect on the pulp, caused by its
antibacterial effects.
 Eugenol can be irritating when in direct contact with the oral
mucosa or pulp
 Contraindication: direct pulp capping
 When properly mixed, ZOE has a pH of 7
 Makes it very biocompatible with tooth structure

9. Zinc Oxide Eugenol
 Advantages
 Wide variety of uses
 Sedative to the pulp
 Easily manipulated
 Disadvantages
 Low strength
 High solubility
 Unable to be used under composite
restorations and indirect
restorations cemented with resin or
resin-modified glass ionomer
cements (RMGICs)

10. Contraindications for ZOE?
Sensitivity or allergy to eugenol
Direct pulp capping
Use under resin restorations
Luting: https://youtu.be/8ENwbk5Zcf8
Base: https://youtu.be/yTj6zZDGJYk

11. Zinc Phosphate
 Flecks
 Set through acid-base reaction
 What does this mean?? What type of cure?
 Oldest of the cements
 Has been around for over 100 years
 Not widely used because it more soluble than other cements
 Also causes postoperative sensitivity
 If used, they are applied as permanent luting agents under metal core indirect
restorations, and with the addition of fluoride, for cementation of orthodontic
bands.
 Could also add more powder to provide thermal insulation for use as a high-strength
base/restoration (provisional)

12. Zinc Phosphate
 Powder/liquid system
 The powder is Zinc Oxide; fluoride is added by some
manufacturers to aid in the prevention of carries under
orthodonically banded teeth.
 The liquid is made of phosphoric acid and water
 The chemical reaction (which occurs when the cement
powder is incorporated into the liquid) results in an
exothermic reaction
Exothermic rxn: heat is produced

13. Zinc Phosphate
 Proper mixing technique is required to minimize the exothermic
rxn.
 Controlled by time and temperature
 Incremental incorporation of the powder into the liquid allows for
controlled dissipation of heat
 Mixing over cool glass slab also dissipates the heat
 Make sure the slab does not have moisture on its surface
 Dissipating the heat increases working time

14. Zinc Phosphate
 Initially the pH is 4.2, but becomes neutral within 24-48
hours
 The initially low pH may irritate the pulp in deep
restorations
Contraindication: Direct pulp capping
 Must cover the pulp with low-strength base first (Dycal)
then place zinc phosphate
 Ceramic restorations are not cemented with Zinc
Phosphate

15. Zinc Phospate
 Advantages
Long clinical history
Low film thickness
Inexpensive
High rigidity
 Disadvantages
Initial pulpal irritation and
postoperative sensitivity
Mechanical bond only
Technique-sensitive
proportioning and mixing
Relatively high solubility
https://youtu.be/rtUAS0Ml8Ms

16. Zinc Polycarboxylate
 Durelon
 Acid-base reaction
 First cement developed with an adhesive bond to
tooth structures caused by the affinity of the
cement with the calcium of the tooth substrate
 Used for:
 Final cementation of indirect restorations
 Base
 Selected orthodontic cementation (bands)
 Cementation of SS crowns

17. Polycarboxylate
 Powder/liquid system
Some manufacturers supply predosed capsules for mixing in an
amalgamator
 Powder: Zinc Oxide
 Liquid: aqueous solution (in water) of polyacrylic acid
Polyacrylic acid produces minimal irritation to the pulp

18. Polycarboxylate
 Liquid should not be dispensed before mixing time
 Water loss by evaporation can adversely increase the viscosity
 Lower compressive strength
 Higher solubility
 Retention by chemical and mechanical means
 Chemical: bonds to calcium ions
 Working time can be extended by using cool glass slab
 What type of chemical reaction then??

19. Polycarboxylate
Advantages
Adheres to tooth structure
Nonirritating to the pulp
Inexpensive
Easy to use
Disadvantages
Higher solubility
Lower strength
Shorter working time
https://youtu.be/vYy6GyHv-3E

20. Glass Ionomer Cements
 Introduced in 1969
 Continually evolving
 Most versatile
 Chemically bond with tooth through calcium ions(like
Polycarboxylate)
 Contain aluminum fluorosilicate glass
Gives ability to release and replenish fluoride

21. Glass Ionomer Cements
 Used as:
 Permanent luting agents
 luting of ortho bands and brackets
 Restorative materials
 Low-and high-strength bases
 Core buildups
 CANNOT BOND TO GLAZED PORCELAIN
 Contraindication

22. Glass Ionomer Cements
 Powder/liquid
 Powder: aluminum fluorosilicate glass with barium glass added for
radiopacity
 Liquid: Polyacrylic acid copolymer and water
 When powder and liquid are mixed, the polyacrylic acid attacks the
glass to release fluoride ions
 When mixed properly, GICs are biologically compatible with the pulp
 Can also be dispensed as encapsulated powder/liquid and a
paste/paste system (newest)

23. Glass Ionomer Cements
 Mild to severe postoperative sensitivity have been reported
 Over drying (Desiccating)
 Moisture contamination during first 24 hours
 Fluoride release for the life of the cement has an Anticariogenic
effect
 Increased solubility has been linked to moisture contamination
within the first 24 hours

24. Glass Ionomer Cements
 Type I: luting (cementation)
 Type II: restorative materials
 Type III: liners and bases for cavity preparations
 Similar in chemical composition, but size of powder particles and ratios of
powder and liquid are different

25. Glass Ionomer Cements
 Biocompatible
 Bond to tooth structure
 Fluoride release
 Initially high level of fl2 for the first few days, then fall to low levels
 Can absorb fl2 from in office tx
 Acts as a fluoride reservoir
 Solubility
 Sensitivity to moisture in the first 24 hours is less desirable
 thermal expansion and contraction
 Similar to tooth structure
 Thermal protection

26. Glass Ionomer Cements
 Compressive and Tensile Strength
 Moderately high compression strength
 Weaker in tension and are relatively brittle in then sections
 Wear resistance
 Wear faster than composites
 Surface gets rougher over time
 Cannot be polished like composites
 Radiopacity
 More radiopaque than dentin
 Color
 More opaque than composites
 Translucency and the shades available have improved over the years

27. Glass Ionomer Cements
 Advantages:
 Chemical adhesion to tooth
and metal
 Fluoride release
 Easy to mix
 Moderate strength
 Disadvantages:
 History of postoperative
sensitivity
 Moisture sensitive during setting
 Does not bond to glazed
porcelain
 Marginal solubility
https://youtu.be/7CYpB6jcjbs
https://youtu.be/kwm3XldbHjc
https://youtu.be/SCL-JMYzTxA

28. Hybrid Glass Ionomer Cements
 AKA: Resin-Modified Glass Ionomer Cements (RMGIC)
 Similar to traditional Gis, but resin is added to improve bond strength
and compressive and tensile strength, and decrease solubility
 Virtually insoluble
 Excellent film thickness
 Fluoride release is the same as GIC
 Expansion of the material as it absorbs moisture after setting is of
concern, making it less desirable for cementation of some all-ceramic
indirect restorations because of the risk of fracture.

29. Hybrid Glass Ionomer Cements
Resin-Modified Glass Ionomer Cement
 Advantages:
Good strength
fluoride release
Insoluble
Chemical adhesion to
tooth
Less postoperative
sensitivity
Excellent film thickness
Disadvantages:
Not recommended for all-
ceramic restorations

30. Resin-Based Cements
Modified composite resins with lower viscosity
Used for:
bonding of ceramic indirect restorations
Conventional crowns and bridges
Direct and indirect bonding of orthodontic brackets

31. Bonding Generations

32. 4th Generation System
Three step technique
1.Etch
2.Prime
3.Bond/Adhesive

33. 5th Generation System
Two step system
1.Etch
2.Primer and adhesive (combined)

34. 6th and 7th Generation System
 Self-Adhesive resin cements
 One-step system
 Acidic primers that etch the tooth are combined with the adhesive resin
 During the setting of the self-adhesive resin, the acidic primers undergo a change
from acidic (pH 2) to less acidic (pH 5-6)
 The initial acidity allows the cement to be self-etching
 The smear layer is incorporated into the cement, rather than being dissolved and
rinsed away like in other generations.
 Cement must be COMPLETELY cured
 Uncured resin will irritate the pulp

35. 8th Generation

36. Resin-Based Cements
 Advantages:
 High strength
 Insoluble
 Low wear
 Excellent adherence to tooth
structure
 Can bond all-ceramic
restorations
 Esthetic shades available
 Low chance of postoperative
sensitivity
 Disadvantages:
 The introduction of water or oral
fluids at any points during the
bonding procedure can lead to
lowered bond strength
 Self-adhesive resin cements should
not be applied on exposed pulp or
dentin that is close to the pulp
 Requires additional steps in
preparation of internal restoration
surfaces
 Removal of excess cement may be
difficult