Download Chapter 7 Body Systems

Dental Cements
Chapter 45
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Chapter 45
Lesson 45.1
Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved.
Learning Objectives
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
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Pronounce, define, and spell the Key Terms.
Describe luting cements and differentiate
between permanent and temporary cements.
Discuss the factors that influence luting
cements.
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Introduction
Dental cements are a classification of dental
materials that are routinely used in the placement of
indirect restorations.
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Classification of Cements
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Type I
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Type II

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Luting agents, which include permanent and
temporary cements
Restorative materials, such as glass ionomers
Type III

Liners or bases placed with the cavity preparation
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Luting Agent

Type I dental cements act as adhesives to
hold together the casting and the tooth
structure.

Luting agents are designed to be either permanent
or temporary.
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Fig. 45-1 Casting ready to be cemented.
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Permanent Cement
Permanent cement is used in the long-term
cementation of gold and ceramic restorations
such as inlays/onlays, crowns, bridges,
veneers, and orthodontic
fixed appliances.
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Temporary Cement
Temporary cements are used if a restoration
would have to be removed as a result of
sensitivity or other symptoms, as well as for
the temporary cementation of provisional
coverage.
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Variables Affecting Cements

Mixing time
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Before mixing, follow the manufacturer's
directions.
Measure the powder and liquid according to the
intended use.
Separate the powder and liquid to make space for
mixing.
Divide the powder into increments.
When increment sizes vary, smaller increments
are incorporated first.
Incorporate each powder increment into the liquid
and then mix thoroughly.
(Cont’d)
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Variables Affecting Cements
(Cont’d)

Humidity
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Powder-to-Liquid Ratio
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Premature exposure to warm temperatures or
humidity can result in a loss of water from the
liquid or addition of moisture to the powder.
Incorporating too much or too little powder will
alter the consistency.
Temperature

Some cements undergo an exothermic reaction.
Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved.
Chapter 45
Lesson 45.2
Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved.
Learning Objectives





List the five cements discussed in this chapter
and identify their similarities and differences.
Mix and prepare glass ionomer for cementation.
Mix and prepare composite resin for
cementation.
Mix and prepare zinc oxide-eugenol for
cementation.
Mix and prepare two-paste zinc oxide–eugenol
(Tempbond) for temporary cementation.
(Cont’d)
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Learning Objectives
(Cont’d)



Mix and prepare polycarboxylate for
cementation.
Mix and prepare zinc phosphate for
cementation.
Remove cement from permanent and
temporary cementations.
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Types of Cements
Glass ionomer
Composite resin
Zinc oxide–eugenol
Polycarboxylate
Zinc phosphate
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Glass Ionomer

Chemical makeup


Liquid: itaconic acid, tartaric acid, maleic acid, and
water
Powder: zinc oxide, aluminum oxide, and calcium
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Types of Glass Ionomer
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Type I
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Type II
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For the cementation of metal restorations
and direct-bonded orthodontic brackets
Designed for restoring areas of erosion
near the gingiva
Type III

Used as liners and dentin-bonding agents
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Benefits of Glass Ionomer
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Powder is an acid-soluble calcium. The slow
release of fluoride from this powder helps
inhibit recurrent decay.
Glass ionomer causes less trauma or shock
to the pulp than do many other types of
cements.
Glass ionomer has a low solubility in the
mouth.
It adheres to a slightly moist tooth surface.
It has a very thin film thickness, which is
excellent for seating ease.
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Supply of Glass Ionomer

Type I (powder/liquid)
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
Mixed manually on a paper pad or a cool, dry
glass slab (slab increases the working time of the
cement)
Type I (premeasured capsules)

Triturated and expressed through a dispenser.
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Fig. 45-3 Premeasured capsules of glass ionomer
permanent cement.
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Composite Resin

Chemical makeup



Physical properties comparable to those of
composite resins
Low film thickness (thinner in consistency than
composite resins)
Insoluble in the mouth
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Uses of Composite Resin
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Cementation of ceramic or resin inlays and
onlays.
Cementation of ceramic veneers.
Cementation of orthodontic bands.
Direct bonding of orthodontic brackets.
Cementation of all metal castings.
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Supply of Composite Resin
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Powder and liquid mix
Syringe-type applicator
Base and catalyst
Light-cure/dual-cure system

Recommended portions of either application are
dispensed onto a paper pad and mixed rapidly
with the use of a spatula.
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Fig. 45-4 Examples of composite resin cements supplied in
variable systems.
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ZOE

Chemical makeup


Liquid: eugenol, H2O, acetic acid, zinc acetate,
and calcium chloride
Powder: zinc oxide, magnesium oxide,
and silica
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Types of ZOE
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Type I


Lacks strength and long-term durability and is
used for temporary cementation of provisional
coverage
Type II

Has reinforcing agents added for the permanent
cementation of cast restorations
or appliances
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Fig. 45-5 ZOE type I cement for temporary cementation.
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Fig. 45-6 ZOE type II cement for permanent cementation.
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Supply of ZOE
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Type I (paste)
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Supplied as a two-paste system as
temporary cement
Pastes dispensed in equal lengths
on a paper pad and mixed
Type II (liquid/powder)

Mixed on an oil-resistant paper pad
 Mixing time of 30 to 60 seconds
 Setting time in the mouth of 3 to 5 minutes
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Polycarboxylate Cements

Chemical makeup

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Liquid: polyacrylic acid, itaconic acid, maleic acid,
tartaric acid, and water
Powder: zinc oxide
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Use of Polycarboxylate
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Permanent cement for cast restorations,
stainless-steel crowns, and orthodontic bands
As a nonirritating base under both composite
and amalgam restorations
As an intermediate restoration
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Supply of Polycarboxylate
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Powder/liquid
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Liquid may be measured with the use of either a
plastic squeeze bottle or a calibrated syringe-type
liquid dispenser.
The liquid has a limited shelf life because it
thickens as its water evaporates.
Mixing is carried out on a nonabsorbent paper
pad.
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Fig. 45-7 Powder and calibrated syringe of
polycarboxylate cement.
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Zinc Phosphate

Chemical makeup


Liquid: phosphoric acid, aluminum phosphate, and
water
Powder: zinc oxide, magnesium oxide, and silica
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Types of Zinc Phosphate

Type I (fine grain)


This type is used for the permanent cementation
of cast restorations such as crowns, inlays, onlays,
and bridges. It provides the very thin film layer
necessary for accurate seating of castings.
Type II (medium grain)

This type is recommended for use as an insulating
base for deep cavity preparations.
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Supply of Zinc Phosphate

Type I (powder/liquid)



Powder is divided into increments of varying
sizes.
It is critical that the powder be added to the liquid
in very small increments.
The cement must be spatulated slowly over a wide
area of a cool, dry, thick glass slab to dissipate the
heat.
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Fig. 45-8 Zinc phosphate type I cement for
permanent cementation.
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Cement Removal

Operator preparedness and knowledge
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

The procedure requires certain instruments:
• Explorer, mouth mirror, excavator
Use a fulcrum.
Use dental floss in and around the
embrasure areas.
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Fig. 45-9 Excess cement must be removed after the
setting process.
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